Commit Graph

674 Commits

Author SHA1 Message Date
Aaron Tomlin
2cddfc2e8f tracing: Add bitmask-list option for human-readable bitmask display
Add support for displaying bitmasks in human-readable list format (e.g.,
0,2-5,7) in addition to the default hexadecimal bitmap representation.
This is particularly useful when tracing CPU masks and other large
bitmasks where individual bit positions are more meaningful than their
hexadecimal encoding.

When the "bitmask-list" option is enabled, the printk "%*pbl" format
specifier is used to render bitmasks as comma-separated ranges, making
trace output easier to interpret for complex CPU configurations and
large bitmask values.

Link: https://patch.msgid.link/20251226160724.2246493-2-atomlin@atomlin.com
Signed-off-by: Aaron Tomlin <atomlin@atomlin.com>
Signed-off-by: Steven Rostedt (Google) <rostedt@goodmis.org>
2026-01-26 17:00:50 -05:00
Jani Nikula
a592a36e49 Documentation: use a source-read extension for the index link boilerplate
The root document usually has a special :ref:`genindex` link to the
generated index. This is also the case for Documentation/index.rst. The
other index.rst files deeper in the directory hierarchy usually don't.

For SPHINXDIRS builds, the root document isn't Documentation/index.rst,
but some other index.rst in the hierarchy. Currently they have a
".. only::" block to add the index link when doing SPHINXDIRS html
builds.

This is obviously very tedious and repetitive. The link is also added to
all index.rst files in the hierarchy for SPHINXDIRS builds, not just the
root document.

Put the boilerplate in a sphinx-includes/subproject-index.rst file, and
include it at the end of the root document for subproject builds in an
ad-hoc source-read extension defined in conf.py.

For now, keep having the boilerplate in translations, because this
approach currently doesn't cover translated index link headers.

Cc: Jonathan Corbet <corbet@lwn.net>
Cc: Mauro Carvalho Chehab <mchehab@kernel.org>
Cc: Randy Dunlap <rdunlap@infradead.org>
Signed-off-by: Jani Nikula <jani.nikula@intel.com>
Tested-by: Mauro Carvalho Chehab <mchehab+huawei@kernel.org>
Reviewed-by: Mauro Carvalho Chehab <mchehab+huawei@kernel.org>
[jc: did s/doctree/kern_doc_dir/ ]
Signed-off-by: Jonathan Corbet <corbet@lwn.net>
Message-ID: <20260123143149.2024303-1-jani.nikula@intel.com>
2026-01-23 11:59:34 -07:00
Petr Vorel
a02857e734 Documentation/trace: Fix links to other documents
Link to another document does not require 'file:'. Removing it fixes
links in generated html docs.

Signed-off-by: Petr Vorel <pvorel@suse.cz>
Signed-off-by: Jonathan Corbet <corbet@lwn.net>
Message-ID: <20260111223643.174812-2-pvorel@suse.cz>
2026-01-12 09:31:19 -07:00
Gabriele Monaco
e4a1e415eb Documentation/rv: Adapt documentation after da_monitor refactoring
Previous changes refactored the da_monitor header file to avoid using
macros. This implies a few changes in how to import and use da_monitor
helpers:

 DECLARE_DA_MON_<TYPE>(name, type) is substituted by
 #define RV_MON_TYPE RV_MON_<TYPE>

 da_handle_event_<name>() is substituted by
 da_handle_event()

Update the documentation to reflect the changes.

Reviewed-by: Nam Cao <namcao@linutronix.de>
Link: https://lore.kernel.org/r/20251126104241.291258-4-gmonaco@redhat.com
Signed-off-by: Gabriele Monaco <gmonaco@redhat.com>
2026-01-12 07:43:50 +01:00
Shuai Xue
8236fc613d Documentation: tracing: Add PCI tracepoint documentation
The PCI tracing system provides tracepoints to monitor critical hardware
events that can impact system performance and reliability. Add
documentation about it.

Signed-off-by: Shuai Xue <xueshuai@linux.alibaba.com>
[bhelgaas: squash fixes:
https://lore.kernel.org/r/20260108013956.14351-2-bagasdotme@gmail.com
https://lore.kernel.org/r/20260108013956.14351-3-bagasdotme@gmail.com]
Signed-off-by: Bjorn Helgaas <bhelgaas@google.com>
Reviewed-by: Ilpo Järvinen <ilpo.jarvinen@linux.intel.com>
Link: https://patch.msgid.link/20251210132907.58799-4-xueshuai@linux.alibaba.com
2026-01-08 10:06:19 -06:00
Soham Metha
7508b208f1 Documentation/rv: Fix dead link to monitor_synthesis.rst
The file 'da_monitor_synthesis.rst' was renamed to 'monitor_synthesis.rst' in
commit f40a7c0602
("Documentation/rv: Prepare monitor synthesis document for LTL inclusion").

Signed-off-by: Soham Metha <sohammetha01@gmail.com>
Fixes: f40a7c0602 ("Documentation/rv: Prepare monitor synthesis document for LTL inclusion")
Acked-by: Gabriele Monaco <gmonaco@redhat.com>
Signed-off-by: Jonathan Corbet <corbet@lwn.net>
Message-ID: <20251204032452.9523-1-sohammetha01@gmail.com>
2025-12-22 15:30:26 -07:00
James Clark
19214ad0a4 coresight: docs: Document etm4x timestamp interval option
Document how the new field is used, maximum value and the interaction
with SYNC timestamps.

Tested-by: Leo Yan <leo.yan@arm.com>
Signed-off-by: James Clark <james.clark@linaro.org>
Reviewed-by: Leo Yan <leo.yan@arm.com>
Signed-off-by: Suzuki K Poulose <suzuki.poulose@arm.com>
Link: https://lore.kernel.org/r/20251128-james-cs-syncfreq-v8-13-4d319764cc58@linaro.org
2025-12-22 15:30:54 +00:00
Linus Torvalds
69c5079b49 tracing updates for v6.19:
- Merge branch shared with kprobes on extending trace options
 
   The trace options were defined by a 32 bit variable. This limits the
   tracing instances to have a total of 32 different options. As that limit
   has been hit, and more options are being added, increase the option mask
   to a 64 bit number, doubling the number of options available.
 
   As this is required for the kprobe topic branches as well as the tracing
   topic branch, a separate branch was created and merged into both.
 
 - Make trace_user_fault_read() available for the rest of tracing
 
   The function trace_user_fault_read() is used by trace_marker file read to
   allow reading user space to be done fast and without locking or
   allocations. Make this available so that the system call trace events can
   use it too.
 
 - Have system call trace events read user space values
 
   Now that the system call trace events callbacks are called in a faultable
   context, take advantage of this and read the user space buffers for
   various system calls. For example, show the path name of the openat system
   call instead of just showing the pointer to that path name in user space.
   Also show the contents of the buffer of the write system call. Several
   system call trace events are updated to make tracing into a light weight
   strace tool for all applications in the system.
 
 - Update perf system call tracing to do the same
 
 - And a config and syscall_user_buf_size file to control the size of the buffer
 
   Limit the amount of data that can be read from user space. The default
   size is 63 bytes but that can be expanded to 165 bytes.
 
 - Allow the persistent ring buffer to print system calls normally
 
   The persistent ring buffer prints trace events by their type and ignores
   the print_fmt. This is because the print_fmt may change from kernel to
   kernel. As the system call output is fixed by the system call ABI itself,
   there's no reason to limit that. This makes reading the system call events
   in the persistent ring buffer much nicer and easier to understand.
 
 - Add options to show text offset to function profiler
 
   The function profiler that counts the number of times a function is hit
   currently lists all functions by its name and offset. But this becomes
   ambiguous when there are several functions with the same name. Add a
   tracing option that changes the output to be that of _text+offset
   instead. Now a user space tool can use this information to map the
   _text+offset to the unique function it is counting.
 
 - Report bad dynamic event command
 
   If a bad command is passed to the dynamic_events file, report it properly
   in the error log.
 
 - Clean up tracer options
 
   Clean up the tracer option code a bit, by removing some useless code and
   also using switch statements instead of a series of if statements.
 
 - Have tracing options be instance specific
 
   Tracers can have their own options (function tracer, irqsoff tracer,
   function graph tracer, etc). But now that the same tracer can be enabled
   in multiple trace instances, their options are still global. The API is
   per instance, thus changing one affects other instances. This isn't even
   consistent, as the option take affect differently depending on when an
   tracer started in an instance.  Make the options for instances only affect
   the instance it is changed under.
 
 - Optimize pid_list lock contention
 
   Whenever the pid_list is read, it uses a spin lock. This happens at every
   sched switch. Taking the lock at sched switch can be removed by instead
   using a seqlock counter.
 
 - Clean up the trace trigger structures
 
   The trigger code uses two different structures to implement a single
   tigger. This was due to trying to reuse code for the two different types
   of triggers (always on trigger, and count limited trigger). But by adding
   a single field to one structure, the other structure could be absorbed
   into the first structure making he code easier to understand.
 
 - Create a bulk garbage collector for trace triggers
 
   If user space has triggers for several hundreds of events and then removes
   them, it can take several seconds to complete. This is because each
   removal calls the slow tracepoint_synchronize_unregister() that can take
   hundreds of milliseconds to complete. Instead, create a helper thread that
   will do the clean up. When a trigger is removed, it will create the
   kthread if it isn't already created, and then add the trigger to a llist.
   The kthread will take the items off the llist, call
   tracepoint_synchronize_unregister(), and then remove the items it took
   off. It will then check if there's more items to free before sleeping.
 
   This makes user space removing all these triggers to finish in less than a
   second.
 
 - Allow function tracing of some of the tracing infrastructure code
 
   Because the tracing code can cause recursion issues if it is traced by the
   function tracer the entire tracing directory disables function tracing.
   But not all of tracing causes issues if it is traced. Namely, the event
   tracing code. Add a config that enables some of the tracing code to be
   traced to help in debugging it. Note, when this is enabled, it does add
   noise to general function tracing, especially if events are enabled as
   well (which is a common case).
 
 - Add boot-time backup instance for persistent buffer
 
   The persistent ring buffer is used mostly for kernel crash analysis in the
   field. One issue is that if there's a crash, the data in the persistent
   ring buffer must be read before tracing can begin using it. This slows
   down the boot process. Once tracing starts in the persistent ring buffer,
   the old data must be freed and the addresses no longer match and old
   events can't be in the buffer with new events.
 
   Create a way to create a backup buffer that copies the persistent ring
   buffer at boot up. Then after a crash, the always on tracer can begin
   immediately as well as the normal boot process while the crash analysis
   tooling uses the backup buffer. After the backup buffer is finished being
   read, it can be removed.
 
 - Enable function graph args and return address options at the same time
 
   Currently the when reading of arguments in the function graph tracer is
   enabled, the option to record the parent function in the entry event can
   not be enabled. Update the code so that it can.
 
 - Add new struct_offset() helper macro
 
   Add a new macro that takes a pointer to a structure and a name of one of
   its members and it will return the offset of that member. This allows the
   ring buffer code to simplify the following:
 
   From:  size = struct_size(entry, buf, cnt - sizeof(entry->id));
     To:  size = struct_offset(entry, id) + cnt;
 
   There should be other simplifications that this macro can help out with as
   well.
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Merge tag 'trace-v6.19' of git://git.kernel.org/pub/scm/linux/kernel/git/trace/linux-trace

Pull tracing updates from Steven Rostedt:

 - Extend tracing option mask to 64 bits

   The trace options were defined by a 32 bit variable. This limits the
   tracing instances to have a total of 32 different options. As that
   limit has been hit, and more options are being added, increase the
   option mask to a 64 bit number, doubling the number of options
   available.

   As this is required for the kprobe topic branches as well as the
   tracing topic branch, a separate branch was created and merged into
   both.

 - Make trace_user_fault_read() available for the rest of tracing

   The function trace_user_fault_read() is used by trace_marker file
   read to allow reading user space to be done fast and without locking
   or allocations. Make this available so that the system call trace
   events can use it too.

 - Have system call trace events read user space values

   Now that the system call trace events callbacks are called in a
   faultable context, take advantage of this and read the user space
   buffers for various system calls. For example, show the path name of
   the openat system call instead of just showing the pointer to that
   path name in user space. Also show the contents of the buffer of the
   write system call. Several system call trace events are updated to
   make tracing into a light weight strace tool for all applications in
   the system.

 - Update perf system call tracing to do the same

 - And a config and syscall_user_buf_size file to control the size of
   the buffer

   Limit the amount of data that can be read from user space. The
   default size is 63 bytes but that can be expanded to 165 bytes.

 - Allow the persistent ring buffer to print system calls normally

   The persistent ring buffer prints trace events by their type and
   ignores the print_fmt. This is because the print_fmt may change from
   kernel to kernel. As the system call output is fixed by the system
   call ABI itself, there's no reason to limit that. This makes reading
   the system call events in the persistent ring buffer much nicer and
   easier to understand.

 - Add options to show text offset to function profiler

   The function profiler that counts the number of times a function is
   hit currently lists all functions by its name and offset. But this
   becomes ambiguous when there are several functions with the same
   name.

   Add a tracing option that changes the output to be that of
   '_text+offset' instead. Now a user space tool can use this
   information to map the '_text+offset' to the unique function it is
   counting.

 - Report bad dynamic event command

   If a bad command is passed to the dynamic_events file, report it
   properly in the error log.

 - Clean up tracer options

   Clean up the tracer option code a bit, by removing some useless code
   and also using switch statements instead of a series of if
   statements.

 - Have tracing options be instance specific

   Tracers can have their own options (function tracer, irqsoff tracer,
   function graph tracer, etc). But now that the same tracer can be
   enabled in multiple trace instances, their options are still global.
   The API is per instance, thus changing one affects other instances.
   This isn't even consistent, as the option take affect differently
   depending on when an tracer started in an instance. Make the options
   for instances only affect the instance it is changed under.

 - Optimize pid_list lock contention

   Whenever the pid_list is read, it uses a spin lock. This happens at
   every sched switch. Taking the lock at sched switch can be removed by
   instead using a seqlock counter.

 - Clean up the trace trigger structures

   The trigger code uses two different structures to implement a single
   tigger. This was due to trying to reuse code for the two different
   types of triggers (always on trigger, and count limited trigger). But
   by adding a single field to one structure, the other structure could
   be absorbed into the first structure making he code easier to
   understand.

 - Create a bulk garbage collector for trace triggers

   If user space has triggers for several hundreds of events and then
   removes them, it can take several seconds to complete. This is
   because each removal calls tracepoint_synchronize_unregister() that
   can take hundreds of milliseconds to complete.

   Instead, create a helper thread that will do the clean up. When a
   trigger is removed, it will create the kthread if it isn't already
   created, and then add the trigger to a llist. The kthread will take
   the items off the llist, call tracepoint_synchronize_unregister(),
   and then remove the items it took off. It will then check if there's
   more items to free before sleeping.

   This makes user space removing all these triggers to finish in less
   than a second.

 - Allow function tracing of some of the tracing infrastructure code

   Because the tracing code can cause recursion issues if it is traced
   by the function tracer the entire tracing directory disables function
   tracing. But not all of tracing causes issues if it is traced.
   Namely, the event tracing code. Add a config that enables some of the
   tracing code to be traced to help in debugging it. Note, when this is
   enabled, it does add noise to general function tracing, especially if
   events are enabled as well (which is a common case).

 - Add boot-time backup instance for persistent buffer

   The persistent ring buffer is used mostly for kernel crash analysis
   in the field. One issue is that if there's a crash, the data in the
   persistent ring buffer must be read before tracing can begin using
   it. This slows down the boot process. Once tracing starts in the
   persistent ring buffer, the old data must be freed and the addresses
   no longer match and old events can't be in the buffer with new
   events.

   Create a way to create a backup buffer that copies the persistent
   ring buffer at boot up. Then after a crash, the always on tracer can
   begin immediately as well as the normal boot process while the crash
   analysis tooling uses the backup buffer. After the backup buffer is
   finished being read, it can be removed.

 - Enable function graph args and return address options at the same
   time

   Currently the when reading of arguments in the function graph tracer
   is enabled, the option to record the parent function in the entry
   event can not be enabled. Update the code so that it can.

 - Add new struct_offset() helper macro

   Add a new macro that takes a pointer to a structure and a name of one
   of its members and it will return the offset of that member. This
   allows the ring buffer code to simplify the following:

   From:  size = struct_size(entry, buf, cnt - sizeof(entry->id));
     To:  size = struct_offset(entry, id) + cnt;

   There should be other simplifications that this macro can help out
   with as well

* tag 'trace-v6.19' of git://git.kernel.org/pub/scm/linux/kernel/git/trace/linux-trace: (42 commits)
  overflow: Introduce struct_offset() to get offset of member
  function_graph: Enable funcgraph-args and funcgraph-retaddr to work simultaneously
  tracing: Add boot-time backup of persistent ring buffer
  ftrace: Allow tracing of some of the tracing code
  tracing: Use strim() in trigger_process_regex() instead of skip_spaces()
  tracing: Add bulk garbage collection of freeing event_trigger_data
  tracing: Remove unneeded event_mutex lock in event_trigger_regex_release()
  tracing: Merge struct event_trigger_ops into struct event_command
  tracing: Remove get_trigger_ops() and add count_func() from trigger ops
  tracing: Show the tracer options in boot-time created instance
  ftrace: Avoid redundant initialization in register_ftrace_direct
  tracing: Remove unused variable in tracing_trace_options_show()
  fgraph: Make fgraph_no_sleep_time signed
  tracing: Convert function graph set_flags() to use a switch() statement
  tracing: Have function graph tracer option sleep-time be per instance
  tracing: Move graph-time out of function graph options
  tracing: Have function graph tracer option funcgraph-irqs be per instance
  trace/pid_list: optimize pid_list->lock contention
  tracing: Have function graph tracer define options per instance
  tracing: Have function tracer define options per instance
  ...
2025-12-05 09:51:37 -08:00
Tomas Glozar
b9f6a40dc3 Documentation/trace: Specify exact priority for timerlat
The timerlat tracer documentation mentions that threads are created with
real-time priority, but does not mention which priority and scheduling
class is used.

Add the information so that users do not have to look it up in
trace_osnoise.c.

Signed-off-by: Tomas Glozar <tglozar@redhat.com>
Acked-by: Steven Rostedt (Google) <rostedt@goodmis.org>
Signed-off-by: Jonathan Corbet <corbet@lwn.net>
Message-ID: <20251010083338.478961-9-tglozar@redhat.com>
2025-11-05 11:19:20 -07:00
Steven Rostedt
299ea67e6a tracing: Add a config and syscall_user_buf_size file to limit amount written
When a system call that can copy user space addresses into the ring
buffer, it can copy up to 511 bytes of data. This can waste precious ring
buffer space if the user isn't interested in the output. Add a new file
"syscall_user_buf_size" that gets initialized to a new config
CONFIG_SYSCALL_BUF_SIZE_DEFAULT that defaults to 63.

The config also is used to limit how much perf can read from user space.

Also lower the max down to 165, as this isn't to record everything that a
system call may be passing through to the kernel. 165 is more than enough.

The reason for 165 is because adding one for the nul terminating byte, as
well as possibly needing to append the "..." string turns it into 170
bytes. As this needs to save up to 3 arguments and 3 * 170 is 510 which
fits nicely in 512 bytes (a power of 2).

Cc: Masami Hiramatsu <mhiramat@kernel.org>
Cc: Mark Rutland <mark.rutland@arm.com>
Cc: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Namhyung Kim <namhyung@kernel.org>
Cc: Takaya Saeki <takayas@google.com>
Cc: Tom Zanussi <zanussi@kernel.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Ian Rogers <irogers@google.com>
Cc: Douglas Raillard <douglas.raillard@arm.com>
Cc: Arnaldo Carvalho de Melo <acme@kernel.org>
Cc: Jiri Olsa <jolsa@kernel.org>
Cc: Adrian Hunter <adrian.hunter@intel.com>
Cc: Ingo Molnar <mingo@redhat.com>
Link: https://lore.kernel.org/20251028231148.260068913@kernel.org
Signed-off-by: Steven Rostedt (Google) <rostedt@goodmis.org>
2025-10-28 20:10:59 -04:00
Bagas Sanjaya
b8874ea3d0 Documentation: trace: histogram: Convert ftrace docs cross-reference
In brief "Extended error information" section, details on error
condition is referred to ftrace docs, which is written in :file:
directive instead of a proper cross-reference. Convert it.

Reviewed-by: Tom Zanussi <zanussi@kernel.org>
Signed-off-by: Bagas Sanjaya <bagasdotme@gmail.com>
Acked-by: Steven Rostedt (Google) <rostedt@goodmis.org>
Signed-off-by: Jonathan Corbet <corbet@lwn.net>
Message-ID: <20250916054202.582074-7-bagasdotme@gmail.com>
2025-09-18 11:49:26 -06:00
Bagas Sanjaya
fa06220f34 Documentation: trace: histogram-design: Wrap introductory note in note:: directive
Use Sphinx note:: directive for the introductory note at the beginning
of docs, instead of aligned-text paragraph that renders as definition
list.

Reviewed-by: Tom Zanussi <zanussi@kernel.org>
Reviewed-by: Masami Hiramatsu (Google) <mhiramat@kernel.org>
Signed-off-by: Bagas Sanjaya <bagasdotme@gmail.com>
Acked-by: Steven Rostedt (Google) <rostedt@goodmis.org>
Signed-off-by: Jonathan Corbet <corbet@lwn.net>
Message-ID: <20250916054202.582074-6-bagasdotme@gmail.com>
2025-09-18 11:49:26 -06:00
Bagas Sanjaya
8c716e87ea Documentation: trace: historgram-design: Separate sched_waking histogram section heading and the following diagram
Section heading for sched_waking histogram is shown as normal paragraph
instead due to codeblock marker for the following diagram being in the
same line as the section underline. Separate them.

Fixes: daceabf1b4 ("tracing/doc: Fix ascii-art in histogram-design.rst")
Reviewed-by: Tom Zanussi <zanussi@kernel.org>
Reviewed-by: Masami Hiramatsu (Google) <mhiramat@kernel.org>
Signed-off-by: Bagas Sanjaya <bagasdotme@gmail.com>
Acked-by: Steven Rostedt (Google) <rostedt@goodmis.org>
Signed-off-by: Jonathan Corbet <corbet@lwn.net>
Message-ID: <20250916054202.582074-5-bagasdotme@gmail.com>
2025-09-18 11:49:26 -06:00
Bagas Sanjaya
f867a298ac Documentation: trace: histogram-design: Trim trailing vertices in diagram explanation text
Diagram explanation text is supposed to be interleaved commentary
between diagram parts that are spread out, but it outputs ugly in
htmldocs due to trailing vertices as if both the explanation and the
diagram are in the same literal code block.

Trim trailing vertices.

Reviewed-by: Tom Zanussi <zanussi@kernel.org>
Reviewed-by: Masami Hiramatsu (Google) <mhiramat@kernel.org>
Signed-off-by: Bagas Sanjaya <bagasdotme@gmail.com>
Acked-by: Steven Rostedt (Google) <rostedt@goodmis.org>
Signed-off-by: Jonathan Corbet <corbet@lwn.net>
Message-ID: <20250916054202.582074-4-bagasdotme@gmail.com>
2025-09-18 11:49:26 -06:00
Bagas Sanjaya
348b7ca8d3 Documentation: trace: histogram: Fix histogram trigger subsection number order
Section numbering in subsections of "Histogram Trigger Command" sections
is inconsistent in order. In particular, "'hist' trigger examples" is
erroneously numbered as 6.2, which is a leftover from  b8df4a3634
("tracing: Move hist trigger Documentation to histogram.txt").

Fix the order.

Reviewed-by: Tom Zanussi <zanussi@kernel.org>
Reviewed-by: Masami Hiramatsu (Google) <mhiramat@kernel.org>
Signed-off-by: Bagas Sanjaya <bagasdotme@gmail.com>
Acked-by: Steven Rostedt (Google) <rostedt@goodmis.org>
Signed-off-by: Jonathan Corbet <corbet@lwn.net>
Message-ID: <20250916054202.582074-3-bagasdotme@gmail.com>
2025-09-18 11:49:26 -06:00
Ryan Chung
b65988af71 tracing: fix grammar error in debugging.rst
Signed-off-by: Ryan Chung <seokwoo.chung130@gmail.com>
Acked-by: Steven Rostedt (Google) <rostedt@goodmis.org>
Signed-off-by: Jonathan Corbet <corbet@lwn.net>
Link: https://lore.kernel.org/r/20250831101736.11519-3-seokwoo.chung130@gmail.com
2025-09-03 15:31:48 -06:00
Ryan Chung
d5958c8a09 tracing: rephrase for clearer documentation
Signed-off-by: Ryan Chung <seokwoo.chung130@gmail.com>
Acked-by: Steven Rostedt (Google) <rostedt@goodmis.org>
Signed-off-by: Jonathan Corbet <corbet@lwn.net>
Link: https://lore.kernel.org/r/20250831101736.11519-2-seokwoo.chung130@gmail.com
2025-09-03 15:31:30 -06:00
Mehdi Ben Hadj Khelifa
915fb5caad docs: Corrected typo in trace/events
-Changed 'Dyamically' to 'Dynamically' in trace/events.rst

under sections 7.1 and 7.3

Signed-off-by: Mehdi Ben Hadj Khelifa <mehdi.benhadjkhelifa@gmail.com>
Reviewed-by: Randy Dunlap <rdunlap@infradead.org>
Signed-off-by: Jonathan Corbet <corbet@lwn.net>
Link: https://lore.kernel.org/r/20250819085040.974388-1-mehdi.benhadjkhelifa@gmail.com
2025-08-21 11:59:11 -06:00
Jonathan Corbet
4e18a0b090 Merge branch 'bjorn' into docs-mw
A big set of typo fixes from Bjorn Helgaas
2025-08-18 10:40:16 -06:00
Bjorn Helgaas
29fe206065 Documentation: Fix trace typos
Fix typos.

Signed-off-by: Bjorn Helgaas <bhelgaas@google.com>
Reviewed-by: Randy Dunlap <rdunlap@infradead.org>
Signed-off-by: Jonathan Corbet <corbet@lwn.net>
Link: https://lore.kernel.org/r/20250813200526.290420-9-helgaas@kernel.org
2025-08-18 10:31:20 -06:00
Gopi Krishna Menon
70d476b63a Documentation/rv: Fix minor typo in monitor_synthesis page
Specifically, fix spelling of "practice"

Signed-off-by: Gopi Krishna Menon <krishnagopi487@gmail.com>
Signed-off-by: Jonathan Corbet <corbet@lwn.net>
Link: https://lore.kernel.org/r/20250810111249.93181-1-krishnagopi487@gmail.com
2025-08-12 12:41:20 -06:00
Linus Torvalds
d6f38c1239 tracing changes for 6.17
- Deprecate auto-mounting tracefs to /sys/kernel/debug/tracing
 
   When tracefs was first introduced back in 2014, the directory
   /sys/kernel/tracing was added and is the designated location to mount
   tracefs. To keep backward compatibility, tracefs was auto-mounted in
   /sys/kernel/debug/tracing as well.
 
   All distros now mount tracefs on /sys/kernel/tracing. Having it seen in two
   different locations has lead to various issues and inconsistencies.
 
   The VFS folks have to also maintain debugfs_create_automount() for this
   single user.
 
   It's been over 10 years. Tooling and scripts should start replacing the
   debugfs location with the tracefs one. The reason tracefs was created in the
   first place was to allow access to the tracing facilities without the need
   to configure debugfs into the kernel. Using tracefs should now be more
   robust.
 
   A new config is created: CONFIG_TRACEFS_AUTOMOUNT_DEPRECATED
   which is default y, so that the kernel is still built with the automount.
   This config allows those that want to remove the automount from debugfs to
   do so.
 
   When tracefs is accessed from /sys/kernel/debug/tracing, the following
   printk is triggerd:
 
    pr_warn("NOTICE: Automounting of tracing to debugfs is deprecated and will be removed in 2030\n");
 
   This gives users another 5 years to fix their scripts.
 
 - Use queue_rcu_work() instead of call_rcu() for freeing event filters
 
   The number of filters to be free can be many depending on the number of
   events within an event system. Freeing them from softirq context can
   potentially cause undesired latency. Use the RCU workqueue to free them
   instead.
 
 - Remove pointless memory barriers in latency code
 
   Memory barriers were added to some of the latency code a long time ago with
   the idea of "making them visible", but that's not what memory barriers are
   for. They are to synchronize access between different variables. There was
   no synchronization here making them pointless.
 
 - Remove "__attribute__()" from the type field of event format
 
   When LLVM is used to compile the kernel with CONFIG_DEBUG_INFO_BTF=y and
   PAHOLE_HAS_BTF_TAG=y, some of the format fields get expanded with the
   following:
 
     field:const char * filename;      offset:24;      size:8; signed:0;
 
   Turns into:
 
     field:const char __attribute__((btf_type_tag("user"))) * filename;      offset:24;      size:8; signed:0;
 
   This confuses parsers. Add code to strip these tags from the strings.
 
 - Add eprobe config option CONFIG_EPROBE_EVENTS
 
   Eprobes were added back in 5.15 but were only enabled when another probe was
   enabled (kprobe, fprobe, uprobe, etc). The eprobes had no config option
   of their own. Add one as they should be a separate entity.
 
   It's default y to keep with the old kernels but still has dependencies on
   TRACING and HAVE_REGS_AND_STACK_ACCESS_API.
 
 - Add eprobe documentation
 
   When eprobes were added back in 5.15 no documentation was added to describe
   them. This needs to be rectified.
 
 - Replace open coded cpumask_next_wrap() in move_to_next_cpu()
 
 - Have preemptirq_delay_run() use off-stack CPU mask
 
 - Remove obsolete comment about pelt_cfs event
 
   DECLARE_TRACE() appends "_tp" to trace events now, but the comment above
   pelt_cfs still mentioned appending it manually.
 
 - Remove EVENT_FILE_FL_SOFT_MODE flag
 
   The SOFT_MODE flag was required when the soft enabling and disabling of
   trace events was first introduced. But there was a bug with this approach
   as it only worked for a single instance. When multiple users required soft
   disabling and disabling the code was changed to have a ref count. The
   SOFT_MODE flag is now set iff the ref count is non zero. This is redundant
   and just reading the ref count is good enough.
 
 - Fix typo in comment
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Merge tag 'trace-v6.17' of git://git.kernel.org/pub/scm/linux/kernel/git/trace/linux-trace

Pull tracing updates from Steven Rostedt:

 - Deprecate auto-mounting tracefs to /sys/kernel/debug/tracing

   When tracefs was first introduced back in 2014, the directory
   /sys/kernel/tracing was added and is the designated location to mount
   tracefs. To keep backward compatibility, tracefs was auto-mounted in
   /sys/kernel/debug/tracing as well.

   All distros now mount tracefs on /sys/kernel/tracing. Having it seen
   in two different locations has lead to various issues and
   inconsistencies.

   The VFS folks have to also maintain debugfs_create_automount() for
   this single user.

   It's been over 10 years. Tooling and scripts should start replacing
   the debugfs location with the tracefs one. The reason tracefs was
   created in the first place was to allow access to the tracing
   facilities without the need to configure debugfs into the kernel.
   Using tracefs should now be more robust.

   A new config is created: CONFIG_TRACEFS_AUTOMOUNT_DEPRECATED which is
   default y, so that the kernel is still built with the automount. This
   config allows those that want to remove the automount from debugfs to
   do so.

   When tracefs is accessed from /sys/kernel/debug/tracing, the
   following printk is triggerd:

     pr_warn("NOTICE: Automounting of tracing to debugfs is deprecated and will be removed in 2030\n");

   This gives users another 5 years to fix their scripts.

 - Use queue_rcu_work() instead of call_rcu() for freeing event filters

   The number of filters to be free can be many depending on the number
   of events within an event system. Freeing them from softirq context
   can potentially cause undesired latency. Use the RCU workqueue to
   free them instead.

 - Remove pointless memory barriers in latency code

   Memory barriers were added to some of the latency code a long time
   ago with the idea of "making them visible", but that's not what
   memory barriers are for. They are to synchronize access between
   different variables. There was no synchronization here making them
   pointless.

 - Remove "__attribute__()" from the type field of event format

   When LLVM is used to compile the kernel with CONFIG_DEBUG_INFO_BTF=y
   and PAHOLE_HAS_BTF_TAG=y, some of the format fields get expanded with
   the following:

     field:const char * filename;      offset:24;      size:8; signed:0;

   Turns into:

     field:const char __attribute__((btf_type_tag("user"))) * filename;      offset:24;      size:8; signed:0;

   This confuses parsers. Add code to strip these tags from the strings.

 - Add eprobe config option CONFIG_EPROBE_EVENTS

   Eprobes were added back in 5.15 but were only enabled when another
   probe was enabled (kprobe, fprobe, uprobe, etc). The eprobes had no
   config option of their own. Add one as they should be a separate
   entity.

   It's default y to keep with the old kernels but still has
   dependencies on TRACING and HAVE_REGS_AND_STACK_ACCESS_API.

 - Add eprobe documentation

   When eprobes were added back in 5.15 no documentation was added to
   describe them. This needs to be rectified.

 - Replace open coded cpumask_next_wrap() in move_to_next_cpu()

 - Have preemptirq_delay_run() use off-stack CPU mask

 - Remove obsolete comment about pelt_cfs event

   DECLARE_TRACE() appends "_tp" to trace events now, but the comment
   above pelt_cfs still mentioned appending it manually.

 - Remove EVENT_FILE_FL_SOFT_MODE flag

   The SOFT_MODE flag was required when the soft enabling and disabling
   of trace events was first introduced. But there was a bug with this
   approach as it only worked for a single instance. When multiple users
   required soft disabling and disabling the code was changed to have a
   ref count. The SOFT_MODE flag is now set iff the ref count is non
   zero. This is redundant and just reading the ref count is good
   enough.

 - Fix typo in comment

* tag 'trace-v6.17' of git://git.kernel.org/pub/scm/linux/kernel/git/trace/linux-trace:
  Documentation: tracing: Add documentation about eprobes
  tracing: Have eprobes have their own config option
  tracing: Remove "__attribute__()" from the type field of event format
  tracing: Deprecate auto-mounting tracefs in debugfs
  tracing: Fix comment in trace_module_remove_events()
  tracing: Remove EVENT_FILE_FL_SOFT_MODE flag
  tracing: Remove pointless memory barriers
  tracing/sched: Remove obsolete comment on suffixes
  kernel: trace: preemptirq_delay_test: use offstack cpu mask
  tracing: Use queue_rcu_work() to free filters
  tracing: Replace opencoded cpumask_next_wrap() in move_to_next_cpu()
2025-08-01 10:29:36 -07:00
Linus Torvalds
b1cce98493 It has been a relatively busy cycle for docs, especially the build system:
- The Perl kernel-doc script was added to 2.3.52pre1 just after the turn of
   the millennium.  Over the following 25 years, it accumulated a vast
   amount of cruft, all in a language few people want to deal with anymore.
   Mauro's Python replacement in 6.16 faithfully reproduced all of the cruft
   in the hope of avoiding regressions.  Now that we have a more reasonable
   code base, though, we can work on cleaning it up; many of the changes
   this time around are toward that end.
 
 - A reorganization of the ext4 docs into the usual TOC format.
 
 - Various Chinese translations and updates.
 
 - A new script from Mauro to help with docs-build testing.
 
 - A new document for linked lists
 
 - A sweep through MAINTAINERS fixing broken GitHub git:// repository links.
 
 ...and lots of fixes and updates.
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Merge tag 'docs-6.17' of git://git.lwn.net/linux

Pull documentation updates from Jonathan Corbet:
 "It has been a relatively busy cycle for docs, especially the build
  system:

   - The Perl kernel-doc script was added to 2.3.52pre1 just after the
     turn of the millennium. Over the following 25 years, it accumulated
     a vast amount of cruft, all in a language few people want to deal
     with anymore. Mauro's Python replacement in 6.16 faithfully
     reproduced all of the cruft in the hope of avoiding regressions.

     Now that we have a more reasonable code base, though, we can work
     on cleaning it up; many of the changes this time around are toward
     that end.

   - A reorganization of the ext4 docs into the usual TOC format.

   - Various Chinese translations and updates.

   - A new script from Mauro to help with docs-build testing.

   - A new document for linked lists

   - A sweep through MAINTAINERS fixing broken GitHub git:// repository
     links.

  ...and lots of fixes and updates"

* tag 'docs-6.17' of git://git.lwn.net/linux: (147 commits)
  scripts: add origin commit identification based on specific patterns
  sphinx: kernel_abi: fix performance regression with O=<dir>
  Documentation: core-api: entry: Replace deprecated KVM entry/exit functions
  docs: fault-injection: drop reference to md-faulty
  docs: document linked lists
  scripts: kdoc: make it backward-compatible with Python 3.7
  docs: kernel-doc: emit warnings for ancient versions of Python
  Documentation/rtla: Describe exit status
  Documentation/rtla: Add include common_appendix.rst
  docs: kernel: Clarify printk_ratelimit_burst reset behavior
  Documentation: ioctl-number: Don't repeat macro names
  Documentation: ioctl-number: Shorten macros table
  Documentation: ioctl-number: Correct full path to papr-physical-attestation.h
  Documentation: ioctl-number: Extend "Include File" column width
  Documentation: ioctl-number: Fix linuxppc-dev mailto link
  overlayfs.rst: fix typos
  docs: kdoc: emit a warning for ancient versions of Python
  docs: kdoc: clean up check_sections()
  docs: kdoc: directly access the always-there KdocItem fields
  docs: kdoc: straighten up dump_declaration()
  ...
2025-07-31 08:36:51 -07:00
Linus Torvalds
4ff261e725 Runtime verification changes for 6.17
- Added Linear temporal logic monitors for RT application
 
   Real-time applications may have design flaws causing them to have
   unexpected latency. For example, the applications may raise page faults, or
   may be blocked trying to take a mutex without priority inheritance.
 
   However, while attempting to implement DA monitors for these real-time
   rules, deterministic automaton is found to be inappropriate as the
   specification language. The automaton is complicated, hard to understand,
   and error-prone.
 
   For these cases, linear temporal logic is found to be more suitable. The
   LTL is more concise and intuitive.
 
 - Make printk_deferred() public
 
   The new monitors needed access to printk_deferred(). Make them visible for
   the entire kernel.
 
 - Add a vpanic() to allow for va_list to be passed to panic.
 
 - Add rtapp container monitor.
 
   A collection of monitors that check for common problems with real-time
   applications that cause unexpected latency.
 
 - Add page fault tracepoints to risc-v
 
   These tracepoints are necessary to for the RV monitor to run on risc-v.
 
 - Fix the behaviour of the rv tool with -s and idle tasks.
 
 - Allow the rv tool to gracefully terminate with SIGTERM
 
 - Adjusts dot2c not to create lines over 100 columns
 
 - Properly order nested monitors in the RV Kconfig file
 
 - Return the registration error in all DA monitor instead of 0
 
 - Update and add new sched collection monitors
 
   Replace tss and sncid monitors with more complete sts:
   Not only prove that switches occur in scheduling context and scheduling
   needs interrupt disabled but also that each call to the scheduler
   disables interrupts to (optionally) switch.
 
   New monitor: nrp
    Preemption requires need resched which is cleared by any switch
    (includes a non optimal workaround for /nested/ preemptions)
 
   New monitor: sssw
    suspension requires setting the task to sleepable and, after the
    switch occurs, the task requires a wakeup to come back to runnable
 
   New monitor: opid
    waking and need-resched operations occur with interrupts and
    preemption disabled or in IRQ without explicitly disabling preemption
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Merge tag 'trace-rv-6.17' of git://git.kernel.org/pub/scm/linux/kernel/git/trace/linux-trace

Pull runtime verification updates from Steven Rostedt:

 - Added Linear temporal logic monitors for RT application

   Real-time applications may have design flaws causing them to have
   unexpected latency. For example, the applications may raise page
   faults, or may be blocked trying to take a mutex without priority
   inheritance.

   However, while attempting to implement DA monitors for these
   real-time rules, deterministic automaton is found to be inappropriate
   as the specification language. The automaton is complicated, hard to
   understand, and error-prone.

   For these cases, linear temporal logic is found to be more suitable.
   The LTL is more concise and intuitive.

 - Make printk_deferred() public

   The new monitors needed access to printk_deferred(). Make them
   visible for the entire kernel.

 - Add a vpanic() to allow for va_list to be passed to panic.

 - Add rtapp container monitor.

   A collection of monitors that check for common problems with
   real-time applications that cause unexpected latency.

 - Add page fault tracepoints to risc-v

   These tracepoints are necessary to for the RV monitor to run on
   risc-v.

 - Fix the behaviour of the rv tool with -s and idle tasks.

 - Allow the rv tool to gracefully terminate with SIGTERM

 - Adjusts dot2c not to create lines over 100 columns

 - Properly order nested monitors in the RV Kconfig file

 - Return the registration error in all DA monitor instead of 0

 - Update and add new sched collection monitors

   Replace tss and sncid monitors with more complete sts:

   Not only prove that switches occur in scheduling context and scheduling
   needs interrupt disabled but also that each call to the scheduler
   disables interrupts to (optionally) switch.

   New monitor: nrp
     Preemption requires need resched which is cleared by any switch
     (includes a non optimal workaround for /nested/ preemptions)

   New monitor: sssw
     suspension requires setting the task to sleepable and, after the
     switch occurs, the task requires a wakeup to come back to runnable

   New monitor: opid
      waking and need-resched operations occur with interrupts and
      preemption disabled or in IRQ without explicitly disabling
      preemption"

* tag 'trace-rv-6.17' of git://git.kernel.org/pub/scm/linux/kernel/git/trace/linux-trace: (48 commits)
  rv: Add opid per-cpu monitor
  rv: Add nrp and sssw per-task monitors
  rv: Replace tss and sncid monitors with more complete sts
  sched: Adapt sched tracepoints for RV task model
  rv: Retry when da monitor detects race conditions
  rv: Adjust monitor dependencies
  rv: Use strings in da monitors tracepoints
  rv: Remove trailing whitespace from tracepoint string
  rv: Add da_handle_start_run_event_ to per-task monitors
  rv: Fix wrong type cast in reactors_show() and monitor_reactor_show()
  rv: Fix wrong type cast in monitors_show()
  rv: Remove struct rv_monitor::reacting
  rv: Remove rv_reactor's reference counter
  rv: Merge struct rv_reactor_def into struct rv_reactor
  rv: Merge struct rv_monitor_def into struct rv_monitor
  rv: Remove unused field in struct rv_monitor_def
  rv: Return init error when registering monitors
  verification/rvgen: Organise Kconfig entries for nested monitors
  tools/dot2c: Fix generated files going over 100 column limit
  tools/rv: Stop gracefully also on SIGTERM
  ...
2025-07-30 16:23:12 -07:00
Steven Rostedt
623526ba89 Documentation: tracing: Add documentation about eprobes
Eprobes was added back in 5.15, but was never documented. It became a
"secret" interface even though it has been a topic of several
presentations. For some reason, when eprobes was added, documenting it
never became a priority, until now.

Cc: Mark Rutland <mark.rutland@arm.com>
Cc: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: Namhyung Kim <namhyung@kernel.org>
Cc: Jonathan Corbet <corbet@lwn.net>
Link: https://lore.kernel.org/20250730140945.528135548@kernel.org
Reviewed-by: Randy Dunlap <rdunlap@infradead.org>
Acked-by: Masami Hiramatsu (Google) <mhiramat@kernel.org>
Signed-off-by: Steven Rostedt (Google) <rostedt@goodmis.org>
2025-07-30 10:38:43 -04:00
Gabriele Monaco
614384533d rv: Add opid per-cpu monitor
Add a per-cpu monitor as part of the sched model:
* opid: operations with preemption and irq disabled
    Monitor to ensure wakeup and need_resched occur with irq and
    preemption disabled or in irq handlers.

Cc: Jonathan Corbet <corbet@lwn.net>
Cc: Masami Hiramatsu <mhiramat@kernel.org>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Tomas Glozar <tglozar@redhat.com>
Cc: Juri Lelli <jlelli@redhat.com>
Cc: Clark Williams <williams@redhat.com>
Cc: John Kacur <jkacur@redhat.com>
Link: https://lore.kernel.org/20250728135022.255578-10-gmonaco@redhat.com
Signed-off-by: Gabriele Monaco <gmonaco@redhat.com>
Acked-by: Nam Cao <namcao@linutronix.de>
Tested-by: Nam Cao <namcao@linutronix.de>
Signed-off-by: Steven Rostedt (Google) <rostedt@goodmis.org>
2025-07-28 16:47:35 -04:00
Gabriele Monaco
e8440a88e5 rv: Add nrp and sssw per-task monitors
Add 2 per-task monitors as part of the sched model:

* nrp: need-resched preempts
    Monitor to ensure preemption requires need resched.
* sssw: set state sleep and wakeup
    Monitor to ensure sched_set_state to sleepable leads to sleeping and
    sleeping tasks require wakeup.

Cc: Ingo Molnar <mingo@redhat.com>
Cc: Jonathan Corbet <corbet@lwn.net>
Cc: Masami Hiramatsu <mhiramat@kernel.org>
Cc: Tomas Glozar <tglozar@redhat.com>
Cc: Juri Lelli <jlelli@redhat.com>
Cc: Clark Williams <williams@redhat.com>
Cc: John Kacur <jkacur@redhat.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Link: https://lore.kernel.org/20250728135022.255578-9-gmonaco@redhat.com
Signed-off-by: Gabriele Monaco <gmonaco@redhat.com>
Acked-by: Nam Cao <namcao@linutronix.de>
Tested-by: Nam Cao <namcao@linutronix.de>
Signed-off-by: Steven Rostedt (Google) <rostedt@goodmis.org>
2025-07-28 16:47:34 -04:00
Gabriele Monaco
d0096c2f9c rv: Replace tss and sncid monitors with more complete sts
The tss monitor currently guarantees task switches can happen only while
scheduling, whereas the sncid monitor enforces scheduling occurs with
interrupt disabled.

Replace the monitors with a more comprehensive specification which
implies both but also ensures that:
* each scheduler call disable interrupts to switch
* each task switch happens with interrupts disabled

Cc: Ingo Molnar <mingo@redhat.com>
Cc: Jonathan Corbet <corbet@lwn.net>
Cc: Masami Hiramatsu <mhiramat@kernel.org>
Cc: Nam Cao <namcao@linutronix.de>
Cc: Tomas Glozar <tglozar@redhat.com>
Cc: Juri Lelli <jlelli@redhat.com>
Cc: Clark Williams <williams@redhat.com>
Cc: John Kacur <jkacur@redhat.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Link: https://lore.kernel.org/20250728135022.255578-8-gmonaco@redhat.com
Signed-off-by: Gabriele Monaco <gmonaco@redhat.com>
Signed-off-by: Steven Rostedt (Google) <rostedt@goodmis.org>
2025-07-28 16:47:34 -04:00
Nam Cao
8cfcf9b0e9 verification/rvgen: Support the 'next' operator
The 'next' operator is a unary operator. It is defined as: "next time, the
operand must be true".

Support this operator. For RV monitors, "next time" means the next
invocation of ltl_validate().

Cc: John Ogness <john.ogness@linutronix.de>
Cc: Masami Hiramatsu <mhiramat@kernel.org>
Cc: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
Link: https://lore.kernel.org/9c32cec04dd18d2e956fddd84b0e0a2503daa75a.1752239482.git.namcao@linutronix.de
Signed-off-by: Nam Cao <namcao@linutronix.de>
Tested-by: Gabriele Monaco <gmonaco@redhat.com>
Signed-off-by: Steven Rostedt (Google) <rostedt@goodmis.org>
2025-07-24 10:43:23 -04:00
Nam Cao
e93648e862 Documentation/rv: Add documentation for linear temporal logic monitors
Add documents describing linear temporal logic runtime verification
monitors and how to generate them using rvgen.

Cc: Masami Hiramatsu <mhiramat@kernel.org>
Cc: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
Cc: Gabriele Monaco <gmonaco@redhat.com>
Link: https://lore.kernel.org/be13719e66fd8da147d7c69d5365aa23c52b743f.1751634289.git.namcao@linutronix.de
Signed-off-by: Nam Cao <namcao@linutronix.de>
Signed-off-by: Steven Rostedt (Google) <rostedt@goodmis.org>
2025-07-24 10:42:47 -04:00
Nam Cao
f40a7c0602 Documentation/rv: Prepare monitor synthesis document for LTL inclusion
Monitor synthesis from deterministic automaton and linear temporal logic
have a lot in common. Therefore a single document should describe both.

Change da_monitor_synthesis.rst to monitor_synthesis.rst. LTL monitor
synthesis will be added to this file by a follow-up commit.

This makes the diff far easier to read. If renaming and adding LTL info is
done in a single commit, git wouldn't recognize it as a rename, but a file
removal and a file addition.

While at it, correct the old dot2k commands to the new rvgen commands.

Cc: Masami Hiramatsu <mhiramat@kernel.org>
Cc: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
Link: https://lore.kernel.org/d91c6e4600287f4732d68a014219e576a75ce6dc.1751634289.git.namcao@linutronix.de
Reviewed-by: Gabriele Monaco <gmonaco@redhat.com>
Signed-off-by: Nam Cao <namcao@linutronix.de>
Signed-off-by: Steven Rostedt (Google) <rostedt@goodmis.org>
2025-07-24 10:42:46 -04:00
Steven Rostedt
4d6d0a6263 tracing: Remove redundant config HAVE_FTRACE_MCOUNT_RECORD
Ftrace is tightly coupled with architecture specific code because it
requires the use of trampolines written in assembly. This means that when
a new feature or optimization is made, it must be done for all
architectures. To simplify the approach, CONFIG_HAVE_FTRACE_* configs are
added to denote which architecture has the new enhancement so that other
architectures can still function until they too have been updated.

The CONFIG_HAVE_FTRACE_MCOUNT was added to help simplify the
DYNAMIC_FTRACE work, but now every architecture that implements
DYNAMIC_FTRACE also has HAVE_FTRACE_MCOUNT set too, making it redundant
with the HAVE_DYNAMIC_FTRACE.

Remove the HAVE_FTRACE_MCOUNT config and use DYNAMIC_FTRACE directly where
applicable.

Link: https://lore.kernel.org/all/20250703154916.48e3ada7@gandalf.local.home/

Cc: Masami Hiramatsu <mhiramat@kernel.org>
Cc: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
Cc: Mark Rutland <mark.rutland@arm.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Link: https://lore.kernel.org/20250704104838.27a18690@gandalf.local.home
Signed-off-by: Steven Rostedt (Google) <rostedt@goodmis.org>
2025-07-22 20:15:56 -04:00
Nam Cao
670ff946b9 rv: Add documentation for rtapp monitor
Add documentation describing the rtapp monitor.

Cc: John Ogness <john.ogness@linutronix.de>
Cc: Masami Hiramatsu <mhiramat@kernel.org>
Cc: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
Link: https://lore.kernel.org/df0242d74c12511e82cc9d73c082def91a160c74.1752088709.git.namcao@linutronix.de
Reviewed-by: Gabriele Monaco <gmonaco@redhat.com>
Signed-off-by: Nam Cao <namcao@linutronix.de>
Signed-off-by: Steven Rostedt (Google) <rostedt@goodmis.org>
2025-07-09 15:27:02 -04:00
Ahelenia Ziemiańska
f55b3ca3cf tracing: doc: fix "for a while" typo
Signed-off-by: Ahelenia Ziemiańska <nabijaczleweli@nabijaczleweli.xyz>
Signed-off-by: Jonathan Corbet <corbet@lwn.net>
Link: https://lore.kernel.org/r/xygdnynf7m55p7d27ovzqtdjaa7pua3bxuk5c22cnmoovaji5e@tarta.nabijaczleweli.xyz
2025-07-08 08:14:28 -06:00
Runji Liu
ea08e53d4d docs: trace: boottime-trace.rst: fix typo
Replace misspelled "eariler" with "earlier" and drop the stray period
after "example".

Signed-off-by: Runji Liu <runjiliu.tech@gmail.com>
Acked-by: Steven Rostedt (Google) <rostedt@goodmis.org>
Acked-by: Masami Hiramatsu (Google) <mhiramat@kernel.org>
Signed-off-by: Jonathan Corbet <corbet@lwn.net>
Link: https://lore.kernel.org/r/20250526134046.1042-1-runjiliu.tech@gmail.com
2025-06-09 14:35:07 -06:00
Linus Torvalds
c26f4fbd58 Char/Misc/IIO pull request for 6.16-rc1
Here is the big char/misc/iio and other small driver subsystem pull
 request for 6.16-rc1.
 
 Overall, a lot of individual changes, but nothing major, just the normal
 constant forward progress of new device support and cleanups to existing
 subsystems.  Highlights in here are:
   - Large IIO driver updates and additions and device tree changes
   - Android binder bugfixes and logfile fixes
   - mhi driver updates
   - comedi driver updates
   - counter driver updates and additions
   - coresight driver updates and additions
   - echo driver removal as there are no in-kernel users of it
   - nvmem driver updates
   - spmi driver updates
   - new amd-sbi driver "subsystem" and drivers added
   - rust miscdriver binding documentation fix
   - other small driver fixes and updates (uio, w1, acrn, hpet, xillybus,
     cardreader drivers, fastrpc and others.)
 
 All of these have been in linux-next for quite a while with no reported
 problems.
 
 Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
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Merge tag 'char-misc-6.16-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/gregkh/char-misc

Pull char / misc / iio driver updates from Greg KH:
 "Here is the big char/misc/iio and other small driver subsystem pull
  request for 6.16-rc1.

  Overall, a lot of individual changes, but nothing major, just the
  normal constant forward progress of new device support and cleanups to
  existing subsystems. Highlights in here are:

   - Large IIO driver updates and additions and device tree changes

   - Android binder bugfixes and logfile fixes

   - mhi driver updates

   - comedi driver updates

   - counter driver updates and additions

   - coresight driver updates and additions

   - echo driver removal as there are no in-kernel users of it

   - nvmem driver updates

   - spmi driver updates

   - new amd-sbi driver "subsystem" and drivers added

   - rust miscdriver binding documentation fix

   - other small driver fixes and updates (uio, w1, acrn, hpet,
     xillybus, cardreader drivers, fastrpc and others)

  All of these have been in linux-next for quite a while with no
  reported problems"

* tag 'char-misc-6.16-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/gregkh/char-misc: (390 commits)
  binder: fix yet another UAF in binder_devices
  counter: microchip-tcb-capture: Add watch validation support
  dt-bindings: iio: adc: Add ROHM BD79100G
  iio: adc: add support for Nuvoton NCT7201
  dt-bindings: iio: adc: add NCT7201 ADCs
  iio: chemical: Add driver for SEN0322
  dt-bindings: trivial-devices: Document SEN0322
  iio: adc: ad7768-1: reorganize driver headers
  iio: bmp280: zero-init buffer
  iio: ssp_sensors: optimalize -> optimize
  HID: sensor-hub: Fix typo and improve documentation
  iio: admv1013: replace redundant ternary operator with just len
  iio: chemical: mhz19b: Fix error code in probe()
  iio: adc: at91-sama5d2: use IIO_DECLARE_BUFFER_WITH_TS
  iio: accel: sca3300: use IIO_DECLARE_BUFFER_WITH_TS
  iio: adc: ad7380: use IIO_DECLARE_DMA_BUFFER_WITH_TS
  iio: adc: ad4695: rename AD4695_MAX_VIN_CHANNELS
  iio: adc: ad4695: use IIO_DECLARE_DMA_BUFFER_WITH_TS
  iio: introduce IIO_DECLARE_BUFFER_WITH_TS macros
  iio: make IIO_DMA_MINALIGN minimum of 8 bytes
  ...
2025-06-06 11:50:47 -07:00
Linus Torvalds
b78f1293f9 tracing updates for v6.16:
- Have module addresses get updated in the persistent ring buffer
 
   The addresses of the modules from the previous boot are saved in the
   persistent ring buffer. If the same modules are loaded and an address is
   in the old buffer points to an address that was both saved in the
   persistent ring buffer and is loaded in memory, shift the address to point
   to the address that is loaded in memory in the trace event.
 
 - Print function names for irqs off and preempt off callsites
 
   When ignoring the print fmt of a trace event and just printing the fields
   directly, have the fields for preempt off and irqs off events still show
   the function name (via kallsyms) instead of just showing the raw address.
 
 - Clean ups of the histogram code
 
   The histogram functions saved over 800 bytes on the stack to process
   events as they come in. Instead, create per-cpu buffers that can hold this
   information and have a separate location for each context level (thread,
   softirq, IRQ and NMI).
 
   Also add some more comments to the code.
 
 - Add "common_comm" field for histograms
 
   Add "common_comm" that uses the current->comm as a field in an event
   histogram and acts like any of the other fields of the event.
 
 - Show "subops" in the enabled_functions file
 
   When the function graph infrastructure is used, a subsystem has a "subops"
   that it attaches its callback function to. Instead of the
   enabled_functions just showing a function calling the function that calls
   the subops functions, also show the subops functions that will get called
   for that function too.
 
 - Add "copy_trace_marker" option to instances
 
   There are cases where an instance is created for tooling to write into,
   but the old tooling has the top level instance hardcoded into the
   application. New tools want to consume the data from an instance and not
   the top level buffer. By adding a copy_trace_marker option, whenever the
   top instance trace_marker is written into, a copy of it is also written
   into the instance with this option set. This allows new tools to read what
   old tools are writing into the top buffer.
 
   If this option is cleared by the top instance, then what is written into
   the trace_marker is not written into the top instance. This is a way to
   redirect the trace_marker writes into another instance.
 
 - Have tracepoints created by DECLARE_TRACE() use trace_<name>_tp()
 
   If a tracepoint is created by DECLARE_TRACE() instead of TRACE_EVENT(),
   then it will not be exposed via tracefs. Currently there's no way to
   differentiate in the kernel the tracepoint functions between those that
   are exposed via tracefs or not. A calling convention has been made
   manually to append a "_tp" prefix for events created by DECLARE_TRACE().
   Instead of doing this manually, force it so that all DECLARE_TRACE()
   events have this notation.
 
 - Use __string() for task->comm in some sched events
 
   Instead of hardcoding the comm to be TASK_COMM_LEN in some of the
   scheduler events use __string() which makes it dynamic. Note, if these
   events are parsed by user space it they may break, and the event may have
   to be converted back to the hardcoded size.
 
 - Have function graph "depth" be unsigned to the user
 
   Internally to the kernel, the "depth" field of the function graph event is
   signed due to -1 being used for end of boundary. What actually gets
   recorded in the event itself is zero or positive. Reflect this to user
   space by showing "depth" as unsigned int and be consistent across all
   events.
 
 - Allow an arbitrary long CPU string to osnoise_cpus_write()
 
   The filtering of which CPUs to write to can exceed 256 bytes. If a machine
   has 256 CPUs, and the filter is to filter every other CPU, the write would
   take a string larger than 256 bytes. Instead of using a fixed size buffer
   on the stack that is 256 bytes, allocate it to handle what is passed in.
 
 - Stop having ftrace check the per-cpu data "disabled" flag
 
   The "disabled" flag in the data structure passed to most ftrace functions
   is checked to know if tracing has been disabled or not. This flag was
   added back in 2008 before the ring buffer had its own way to disable
   tracing. The "disable" flag is now not always set when needed, and the
   ring buffer flag should be used in all locations where the disabled is
   needed. Since the "disable" flag is redundant and incorrect, stop using it.
   Fix up some locations that use the "disable" flag to use the ring buffer
   info.
 
 - Use a new tracer_tracing_disable/enable() instead of data->disable flag
 
   There's a few cases that set the data->disable flag to stop tracing, but
   this flag is not consistently used. It is also an on/off switch where if a
   function set it and calls another function that sets it, the called
   function may incorrectly enable it.
 
   Use a new trace_tracing_disable() and tracer_tracing_enable() that uses a
   counter and can be nested. These use the ring buffer flags which are
   always checked making the disabling more consistent.
 
 - Save the trace clock in the persistent ring buffer
 
   Save what clock was used for tracing in the persistent ring buffer and set
   it back to that clock after a reboot.
 
 - Remove unused reference to a per CPU data pointer in mmiotrace functions
 
 - Remove unused buffer_page field from trace_array_cpu structure
 
 - Remove more strncpy() instances
 
 - Other minor clean ups and fixes
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Merge tag 'trace-v6.16' of git://git.kernel.org/pub/scm/linux/kernel/git/trace/linux-trace

Pull tracing updates from Steven Rostedt:

 - Have module addresses get updated in the persistent ring buffer

   The addresses of the modules from the previous boot are saved in the
   persistent ring buffer. If the same modules are loaded and an address
   is in the old buffer points to an address that was both saved in the
   persistent ring buffer and is loaded in memory, shift the address to
   point to the address that is loaded in memory in the trace event.

 - Print function names for irqs off and preempt off callsites

   When ignoring the print fmt of a trace event and just printing the
   fields directly, have the fields for preempt off and irqs off events
   still show the function name (via kallsyms) instead of just showing
   the raw address.

 - Clean ups of the histogram code

   The histogram functions saved over 800 bytes on the stack to process
   events as they come in. Instead, create per-cpu buffers that can hold
   this information and have a separate location for each context level
   (thread, softirq, IRQ and NMI).

   Also add some more comments to the code.

 - Add "common_comm" field for histograms

   Add "common_comm" that uses the current->comm as a field in an event
   histogram and acts like any of the other fields of the event.

 - Show "subops" in the enabled_functions file

   When the function graph infrastructure is used, a subsystem has a
   "subops" that it attaches its callback function to. Instead of the
   enabled_functions just showing a function calling the function that
   calls the subops functions, also show the subops functions that will
   get called for that function too.

 - Add "copy_trace_marker" option to instances

   There are cases where an instance is created for tooling to write
   into, but the old tooling has the top level instance hardcoded into
   the application. New tools want to consume the data from an instance
   and not the top level buffer. By adding a copy_trace_marker option,
   whenever the top instance trace_marker is written into, a copy of it
   is also written into the instance with this option set. This allows
   new tools to read what old tools are writing into the top buffer.

   If this option is cleared by the top instance, then what is written
   into the trace_marker is not written into the top instance. This is a
   way to redirect the trace_marker writes into another instance.

 - Have tracepoints created by DECLARE_TRACE() use trace_<name>_tp()

   If a tracepoint is created by DECLARE_TRACE() instead of
   TRACE_EVENT(), then it will not be exposed via tracefs. Currently
   there's no way to differentiate in the kernel the tracepoint
   functions between those that are exposed via tracefs or not. A
   calling convention has been made manually to append a "_tp" prefix
   for events created by DECLARE_TRACE(). Instead of doing this
   manually, force it so that all DECLARE_TRACE() events have this
   notation.

 - Use __string() for task->comm in some sched events

   Instead of hardcoding the comm to be TASK_COMM_LEN in some of the
   scheduler events use __string() which makes it dynamic. Note, if
   these events are parsed by user space it they may break, and the
   event may have to be converted back to the hardcoded size.

 - Have function graph "depth" be unsigned to the user

   Internally to the kernel, the "depth" field of the function graph
   event is signed due to -1 being used for end of boundary. What
   actually gets recorded in the event itself is zero or positive.
   Reflect this to user space by showing "depth" as unsigned int and be
   consistent across all events.

 - Allow an arbitrary long CPU string to osnoise_cpus_write()

   The filtering of which CPUs to write to can exceed 256 bytes. If a
   machine has 256 CPUs, and the filter is to filter every other CPU,
   the write would take a string larger than 256 bytes. Instead of using
   a fixed size buffer on the stack that is 256 bytes, allocate it to
   handle what is passed in.

 - Stop having ftrace check the per-cpu data "disabled" flag

   The "disabled" flag in the data structure passed to most ftrace
   functions is checked to know if tracing has been disabled or not.
   This flag was added back in 2008 before the ring buffer had its own
   way to disable tracing. The "disable" flag is now not always set when
   needed, and the ring buffer flag should be used in all locations
   where the disabled is needed. Since the "disable" flag is redundant
   and incorrect, stop using it. Fix up some locations that use the
   "disable" flag to use the ring buffer info.

 - Use a new tracer_tracing_disable/enable() instead of data->disable
   flag

   There's a few cases that set the data->disable flag to stop tracing,
   but this flag is not consistently used. It is also an on/off switch
   where if a function set it and calls another function that sets it,
   the called function may incorrectly enable it.

   Use a new trace_tracing_disable() and tracer_tracing_enable() that
   uses a counter and can be nested. These use the ring buffer flags
   which are always checked making the disabling more consistent.

 - Save the trace clock in the persistent ring buffer

   Save what clock was used for tracing in the persistent ring buffer
   and set it back to that clock after a reboot.

 - Remove unused reference to a per CPU data pointer in mmiotrace
   functions

 - Remove unused buffer_page field from trace_array_cpu structure

 - Remove more strncpy() instances

 - Other minor clean ups and fixes

* tag 'trace-v6.16' of git://git.kernel.org/pub/scm/linux/kernel/git/trace/linux-trace: (36 commits)
  tracing: Fix compilation warning on arm32
  tracing: Record trace_clock and recover when reboot
  tracing/sched: Use __string() instead of fixed lengths for task->comm
  tracepoint: Have tracepoints created with DECLARE_TRACE() have _tp suffix
  tracing: Cleanup upper_empty() in pid_list
  tracing: Allow the top level trace_marker to write into another instances
  tracing: Add a helper function to handle the dereference arg in verifier
  tracing: Remove unnecessary "goto out" that simply returns ret is trigger code
  tracing: Fix error handling in event_trigger_parse()
  tracing: Rename event_trigger_alloc() to trigger_data_alloc()
  tracing: Replace deprecated strncpy() with strscpy() for stack_trace_filter_buf
  tracing: Remove unused buffer_page field from trace_array_cpu structure
  tracing: Use atomic_inc_return() for updating "disabled" counter in irqsoff tracer
  tracing: Convert the per CPU "disabled" counter to local from atomic
  tracing: branch: Use trace_tracing_is_on_cpu() instead of "disabled" field
  ring-buffer: Add ring_buffer_record_is_on_cpu()
  tracing: Do not use per CPU array_buffer.data->disabled for cpumask
  ftrace: Do not disabled function graph based on "disabled" field
  tracing: kdb: Use tracer_tracing_on/off() instead of setting per CPU disabled
  tracing: Use tracer_tracing_disable() instead of "disabled" field for ftrace_dump_one()
  ...
2025-05-29 21:04:36 -07:00
Hendrik Hamerlinck
52092c1d50 docs: fix "incase" typo in coresight/panic.rst
Corrects a spelling mistake in Documentation/trace/coresight/panic.rst
where "incase" was used instead of "in case".

Signed-off-by: Hendrik Hamerlinck <hendrik.hamerlinck@hammernet.be>
Signed-off-by: Jonathan Corbet <corbet@lwn.net>
Message-ID: <20250513110931.15072-1-hendrik.hamerlinck@hammernet.be>
2025-05-19 08:02:14 -06:00
Steven Rostedt
ac01fa73f5 tracepoint: Have tracepoints created with DECLARE_TRACE() have _tp suffix
Most tracepoints in the kernel are created with TRACE_EVENT(). The
TRACE_EVENT() macro (and DECLARE_EVENT_CLASS() and DEFINE_EVENT() where in
reality, TRACE_EVENT() is just a helper macro that calls those other two
macros), will create not only a tracepoint (the function trace_<event>()
used in the kernel), it also exposes the tracepoint to user space along
with defining what fields will be saved by that tracepoint.

There are a few places that tracepoints are created in the kernel that are
not exposed to userspace via tracefs. They can only be accessed from code
within the kernel. These tracepoints are created with DEFINE_TRACE()

Most of these tracepoints end with "_tp". This is useful as when the
developer sees that, they know that the tracepoint is for in-kernel only
(meaning it can only be accessed inside the kernel, either directly by the
kernel or indirectly via modules and BPF programs) and is not exposed to
user space.

Instead of making this only a process to add "_tp", enforce it by making
the DECLARE_TRACE() append the "_tp" suffix to the tracepoint. This
requires adding DECLARE_TRACE_EVENT() macros for the TRACE_EVENT() macro
to use that keeps the original name.

Link: https://lore.kernel.org/all/20250418083351.20a60e64@gandalf.local.home/

Cc: netdev <netdev@vger.kernel.org>
Cc: Jiri Olsa <olsajiri@gmail.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: David Ahern <dsahern@kernel.org>
Cc: Juri Lelli <juri.lelli@gmail.com>
Cc: Breno Leitao <leitao@debian.org>
Cc: Alexei Starovoitov <alexei.starovoitov@gmail.com>
Cc: Andrii Nakryiko <andrii.nakryiko@gmail.com>
Cc: Gabriele Monaco <gmonaco@redhat.com>
Cc: Masami Hiramatsu <mhiramat@kernel.org>
Link: https://lore.kernel.org/20250510163730.092fad5b@gandalf.local.home
Acked-by: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
Acked-by: Andrii Nakryiko <andrii@kernel.org>
Signed-off-by: Steven Rostedt (Google) <rostedt@goodmis.org>
2025-05-14 11:19:32 -04:00
Leo Yan
5161890f13 Documentation: coresight: Document AUX pause and resume
This adds description for AUX pause and resume.  It gives introduction
for what's AUX pause and resume and records usage examples.

Signed-off-by: Leo Yan <leo.yan@arm.com>
Reviewed-by: James Clark <james.clark@linaro.org>
Signed-off-by: Suzuki K Poulose <suzuki.poulose@arm.com>
Link: https://lore.kernel.org/r/20250401180708.385396-8-leo.yan@arm.com
2025-05-14 11:56:17 +01:00
Steven Rostedt
7b382efd5e tracing: Allow the top level trace_marker to write into another instances
There are applications that have it hard coded to write into the top level
trace_marker instance (/sys/kernel/tracing/trace_marker). This can be
annoying if a profiler is using that instance for other work, or if it
needs all writes to go into a new instance.

A new option is created called "copy_trace_marker". By default, the top
level has this set, as that is the default buffer that writing into the
top level trace_marker file will go to. But now if an instance is created
and sets this option, all writes into the top level trace_marker will also
be written into that instance buffer just as if an application were to
write into the instance's trace_marker file.

If the top level instance disables this option, then writes to its own
trace_marker and trace_marker_raw files will not go into its buffer.

If no instance has this option set, then the write will return an error
and errno will contain ENODEV.

Cc: Masami Hiramatsu <mhiramat@kernel.org>
Cc: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
Link: https://lore.kernel.org/20250508095639.39f84eda@gandalf.local.home
Signed-off-by: Steven Rostedt (Google) <rostedt@goodmis.org>
2025-05-09 15:19:11 -04:00
Purva Yeshi
f0ba72e655 Documentation: trace: Refactor toctree
Refactor table of contents of kernel tracing subsystem docs to improve
clarity, structure, and organization:

- Reformat sections and add appropriate headings
- Improve section grouping and refine descriptions for each group
- Add docs intro paragraph

Signed-off-by: Purva Yeshi <purvayeshi550@gmail.com>
Link: https://lore.kernel.org/r/20250318113230.24950-2-purvayeshi550@gmail.com
[Bagas: massage commit message and address reviews]
Co-developed-by: Bagas Sanjaya <bagasdotme@gmail.com>
Signed-off-by: Bagas Sanjaya <bagasdotme@gmail.com>
Acked-by: Steven Rostedt (Google) <rostedt@goodmis.org>
Signed-off-by: Jonathan Corbet <corbet@lwn.net>
2025-04-21 10:37:13 -06:00
Purva Yeshi
33583537dd Documentation: trace: Reduce toctree depth
Reduce toctree depth from 2 to 1 so that only docs titles are listed
in the toctree.

Signed-off-by: Purva Yeshi <purvayeshi550@gmail.com>
Link: https://lore.kernel.org/r/20250318113230.24950-1-purvayeshi550@gmail.com
[Bagas: massage commit message]
Signed-off-by: Bagas Sanjaya <bagasdotme@gmail.com>
Acked-by: Steven Rostedt (Google) <rostedt@goodmis.org>
Signed-off-by: Jonathan Corbet <corbet@lwn.net>
2025-04-21 10:37:01 -06:00
Nam Cao
244132c4e5 tracing/timers: Rename the hrtimer_init event to hrtimer_setup
The function hrtimer_init() doesn't exist anymore. It was replaced by
hrtimer_setup().

Thus, rename the hrtimer_init trace event to hrtimer_setup to keep it
consistent.

Signed-off-by: Nam Cao <namcao@linutronix.de>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Link: https://lore.kernel.org/all/cba84c3d853c5258aa3a262363a6eac08e2c7afc.1738746927.git.namcao@linutronix.de
2025-04-05 10:30:17 +02:00
Linus Torvalds
6cb0bd94c0 Persistent buffer cleanups and simplifications for v6.15:
It was mistaken that the physical memory returned from "reserve_mem" had to
 be vmap()'d to get to it from a virtual address. But reserve_mem already
 maps the memory to the virtual address of the kernel so a simple
 phys_to_virt() can be used to get to the virtual address from the physical
 memory returned by "reserve_mem". With this new found knowledge, the
 code can be cleaned up and simplified.
 
 - Enforce that the persistent memory is page aligned
 
   As the buffers using the persistent memory are all going to be
   mapped via pages, make sure that the memory given to the tracing
   infrastructure is page aligned. If it is not, it will print a warning
   and fail to map the buffer.
 
 - Use phys_to_virt() to get the virtual address from reserve_mem
 
   Instead of calling vmap() on the physical memory returned from
   "reserve_mem", use phys_to_virt() instead.
 
   As the memory returned by "memmap" or any other means where a physical
   address is given to the tracing infrastructure, it still needs to
   be vmap(). Since this memory can never be returned back to the buddy
   allocator nor should it ever be memmory mapped to user space, flag
   this buffer and up the ref count. The ref count will keep it from
   ever being freed, and the flag will prevent it from ever being memory
   mapped to user space.
 
 - Use vmap_page_range() for memmap virtual address mapping
 
   For the memmap buffer, instead of allocating an array of struct pages,
   assigning them to the contiguous phsycial memory and then passing that to
   vmap(), use vmap_page_range() instead
 
 - Replace flush_dcache_folio() with flush_kernel_vmap_range()
 
   Instead of calling virt_to_folio() and passing that to
   flush_dcache_folio(), just call flush_kernel_vmap_range() directly.
   This also fixes a bug where if a subbuffer was bigger than PAGE_SIZE
   only the PAGE_SIZE portion would be flushed.
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Merge tag 'trace-ringbuffer-v6.15-3' of git://git.kernel.org/pub/scm/linux/kernel/git/trace/linux-trace

Pull ring-buffer updates from Steven Rostedt:
 "Persistent buffer cleanups and simplifications.

  It was mistaken that the physical memory returned from "reserve_mem"
  had to be vmap()'d to get to it from a virtual address. But
  reserve_mem already maps the memory to the virtual address of the
  kernel so a simple phys_to_virt() can be used to get to the virtual
  address from the physical memory returned by "reserve_mem". With this
  new found knowledge, the code can be cleaned up and simplified.

   - Enforce that the persistent memory is page aligned

     As the buffers using the persistent memory are all going to be
     mapped via pages, make sure that the memory given to the tracing
     infrastructure is page aligned. If it is not, it will print a
     warning and fail to map the buffer.

   - Use phys_to_virt() to get the virtual address from reserve_mem

     Instead of calling vmap() on the physical memory returned from
     "reserve_mem", use phys_to_virt() instead.

     As the memory returned by "memmap" or any other means where a
     physical address is given to the tracing infrastructure, it still
     needs to be vmap(). Since this memory can never be returned back to
     the buddy allocator nor should it ever be memmory mapped to user
     space, flag this buffer and up the ref count. The ref count will
     keep it from ever being freed, and the flag will prevent it from
     ever being memory mapped to user space.

   - Use vmap_page_range() for memmap virtual address mapping

     For the memmap buffer, instead of allocating an array of struct
     pages, assigning them to the contiguous phsycial memory and then
     passing that to vmap(), use vmap_page_range() instead

   - Replace flush_dcache_folio() with flush_kernel_vmap_range()

     Instead of calling virt_to_folio() and passing that to
     flush_dcache_folio(), just call flush_kernel_vmap_range() directly.
     This also fixes a bug where if a subbuffer was bigger than
     PAGE_SIZE only the PAGE_SIZE portion would be flushed"

* tag 'trace-ringbuffer-v6.15-3' of git://git.kernel.org/pub/scm/linux/kernel/git/trace/linux-trace:
  ring-buffer: Use flush_kernel_vmap_range() over flush_dcache_folio()
  tracing: Use vmap_page_range() to map memmap ring buffer
  tracing: Have reserve_mem use phys_to_virt() and separate from memmap buffer
  tracing: Enforce the persistent ring buffer to be page aligned
2025-04-03 16:09:29 -07:00
Steven Rostedt
c44a14f216 tracing: Enforce the persistent ring buffer to be page aligned
Enforce that the address and the size of the memory used by the persistent
ring buffer is page aligned. Also update the documentation to reflect this
requirement.

Link: https://lore.kernel.org/all/CAHk-=whUOfVucfJRt7E0AH+GV41ELmS4wJqxHDnui6Giddfkzw@mail.gmail.com/

Cc: Masami Hiramatsu <mhiramat@kernel.org>
Cc: Mark Rutland <mark.rutland@arm.com>
Cc: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: Vincent Donnefort <vdonnefort@google.com>
Cc: Vlastimil Babka <vbabka@suse.cz>
Cc: Mike Rapoport <rppt@kernel.org>
Cc: Jann Horn <jannh@google.com>
Link: https://lore.kernel.org/20250402144953.412882844@goodmis.org
Suggested-by: Linus Torvalds <torvalds@linux-foundation.org>
Signed-off-by: Steven Rostedt (Google) <rostedt@goodmis.org>
2025-04-02 11:02:26 -04:00
Linus Torvalds
25601e8544 Char/Misc/IIO driver updates for 6.15-rc1
Here is the big set of char, misc, iio, and other smaller driver
 subsystems for 6.15-rc1.  Lots of stuff in here, including:
   - loads of IIO changes and driver updates
   - counter driver updates
   - w1 driver updates
   - faux conversions for some drivers that were abusing the platform bus
     interface
   - coresight driver updates
   - rust miscdevice binding updates based on real-world-use
   - other minor driver updates
 
 All of these have been in linux-next with no reported issues for quite a
 while.
 
 Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
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Merge tag 'char-misc-6.15-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/gregkh/char-misc

Pull char / misc / IIO driver updates from Greg KH:
 "Here is the big set of char, misc, iio, and other smaller driver
  subsystems for 6.15-rc1. Lots of stuff in here, including:

   - loads of IIO changes and driver updates

   - counter driver updates

   - w1 driver updates

   - faux conversions for some drivers that were abusing the platform
     bus interface

   - coresight driver updates

   - rust miscdevice binding updates based on real-world-use

   - other minor driver updates

  All of these have been in linux-next with no reported issues for quite
  a while"

* tag 'char-misc-6.15-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/gregkh/char-misc: (292 commits)
  samples: rust_misc_device: fix markup in top-level docs
  Coresight: Fix a NULL vs IS_ERR() bug in probe
  misc: lis3lv02d: convert to use faux_device
  tlclk: convert to use faux_device
  regulator: dummy: convert to use the faux device interface
  bus: mhi: host: Fix race between unprepare and queue_buf
  coresight: configfs: Constify struct config_item_type
  doc: iio: ad7380: describe offload support
  iio: ad7380: add support for SPI offload
  iio: light: Add check for array bounds in veml6075_read_int_time_ms
  iio: adc: ti-ads7924 Drop unnecessary function parameters
  staging: iio: ad9834: Use devm_regulator_get_enable()
  staging: iio: ad9832: Use devm_regulator_get_enable()
  iio: gyro: bmg160_spi: add of_match_table
  dt-bindings: iio: adc: Add i.MX94 and i.MX95 support
  iio: adc: ad7768-1: remove unnecessary locking
  Documentation: ABI: add wideband filter type to sysfs-bus-iio
  iio: adc: ad7768-1: set MOSI idle state to prevent accidental reset
  iio: adc: ad7768-1: Fix conversion result sign
  iio: adc: ad7124: Benefit of dev = indio_dev->dev.parent in ad7124_parse_channel_config()
  ...
2025-04-01 11:26:08 -07:00
Linus Torvalds
609706855d Documentation fix for runtime verifier
The runtime verifier documents that were created were not referenced
 in the indices, which caused warning when building the documentation
 tree. Those documents are now added to the rv indices.
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Merge tag 'trace-latency-v6.15-3' of git://git.kernel.org/pub/scm/linux/kernel/git/trace/linux-trace

Pull tracing documentation fix from Steven Rostedt:
 "Documentation fix for runtime verifier

  The runtime verifier documents that were created were not referenced
  in the indices, which caused warning when building the documentation
  tree. Those documents are now added to the rv indices"

* tag 'trace-latency-v6.15-3' of git://git.kernel.org/pub/scm/linux/kernel/git/trace/linux-trace:
  Documentation/rv: Add sched pages to the indices
2025-03-31 09:56:08 -07:00
Linus Torvalds
88221ac0d5 Latency tracing changes for v6.15:
- Add some trace events to osnoise and timerlat sample generation
 
   This adds more information to the osnoise and timerlat tracers as well as
   allows BPF programs to be attached to these locations to extract even more
   data.
 
 - Fix to DECLARE_TRACE_CONDITION() macro
 
   It wasn't used but now will be and it happened to be broken causing the
   build to fail.
 
 - Add scheduler specification monitors to runtime verifier (RV)
 
   This is a continuation of Daniel Bristot's work.
 
   RV allows monitors to run and react concurrently. Running the cumulative
   model is equivalent to running single components using the same
   reactors, with the advantage that it's easier to point out which
   specification failed in case of error.
 
   This update introduces nested monitors to RV, in short, the sysfs
   monitor folder will contain a monitor named sched, which is nothing but
   an empty container for other monitors. Controlling the sched monitor
   (enable, disable, set reactors) controls all nested monitors.
 
   The following scheduling monitors are added:
 
   * sco: scheduling context operations
       Monitor to ensure sched_set_state happens only in thread context
   * tss: task switch while scheduling
       Monitor to ensure sched_switch happens only in scheduling context
   * snroc: set non runnable on its own context
       Monitor to ensure set_state happens only in the respective task's context
   * scpd: schedule called with preemption disabled
       Monitor to ensure schedule is called with preemption disabled
   * snep: schedule does not enable preempt
       Monitor to ensure schedule does not enable preempt
   * sncid: schedule not called with interrupt disabled
       Monitor to ensure schedule is not called with interrupt disabled
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Merge tag 'trace-latency-v6.15' of git://git.kernel.org/pub/scm/linux/kernel/git/trace/linux-trace

Pull latency tracing updates from Steven Rostedt:

 - Add some trace events to osnoise and timerlat sample generation

   This adds more information to the osnoise and timerlat tracers as
   well as allows BPF programs to be attached to these locations to
   extract even more data.

 - Fix to DECLARE_TRACE_CONDITION() macro

   It wasn't used but now will be and it happened to be broken causing
   the build to fail.

 - Add scheduler specification monitors to runtime verifier (RV)

   This is a continuation of Daniel Bristot's work.

   RV allows monitors to run and react concurrently. Running the
   cumulative model is equivalent to running single components using the
   same reactors, with the advantage that it's easier to point out which
   specification failed in case of error.

   This update introduces nested monitors to RV, in short, the sysfs
   monitor folder will contain a monitor named sched, which is nothing
   but an empty container for other monitors. Controlling the sched
   monitor (enable, disable, set reactors) controls all nested monitors.

   The following scheduling monitors are added:

     - sco: scheduling context operations
       Monitor to ensure sched_set_state happens only in thread context

     - tss: task switch while scheduling
       Monitor to ensure sched_switch happens only in scheduling context

     - snroc: set non runnable on its own context
       Monitor to ensure set_state happens only in the respective task's context

     - scpd: schedule called with preemption disabled
       Monitor to ensure schedule is called with preemption disabled

     - snep: schedule does not enable preempt
       Monitor to ensure schedule does not enable preempt

     - sncid: schedule not called with interrupt disabled
       Monitor to ensure schedule is not called with interrupt disabled

* tag 'trace-latency-v6.15' of git://git.kernel.org/pub/scm/linux/kernel/git/trace/linux-trace:
  tools/rv: Allow rv list to filter for container
  Documentation/rv: Add docs for the sched monitors
  verification/dot2k: Add support for nested monitors
  tools/rv: Add support for nested monitors
  rv: Add scpd, snep and sncid per-cpu monitors
  rv: Add snroc per-task monitor
  rv: Add sco and tss per-cpu monitors
  rv: Add option for nested monitors and include sched
  sched: Add sched tracepoints for RV task model
  rv: Add license identifiers to monitor files
  tracing: Fix DECLARE_TRACE_CONDITION
  trace/osnoise: Add trace events for samples
2025-03-27 16:03:52 -07:00
Gabriele Monaco
4bb5d82b66 Documentation/rv: Add sched pages to the indices
The pages Documentation/tools/rv/rv-mon-sched.rst and
Documentation/trace/rv/monitor_sched.rst were introduced but not
included in any index.

Add them to the respective indices.

Cc: Jonathan Corbet <corbet@lwn.net>
Link: https://lore.kernel.org/20250327081240.46422-1-gmonaco@redhat.com
Reported-by: Stephen Rothwell <sfr@canb.auug.org.au>
Fixes: 03abeaa63c ("Documentation/rv: Add docs for the sched monitors")
Signed-off-by: Gabriele Monaco <gmonaco@redhat.com>
Signed-off-by: Steven Rostedt (Google) <rostedt@goodmis.org>
2025-03-27 12:02:38 -04:00
Gabriele Monaco
03abeaa63c Documentation/rv: Add docs for the sched monitors
Add man page and kernel documentation for the sched monitors, as sched
is a container of other monitors, document all in the same page.
sched is the first nested monitor, also explain what is a nested monitor
and how enabling containers or children monitors work.

To: Ingo Molnar <mingo@redhat.com>
To: Peter Zijlstra <peterz@infradead.org>
Cc: Juri Lelli <juri.lelli@redhat.com>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Jonathan Corbet <corbet@lwn.net>
Cc: John Kacur <jkacur@redhat.com>
Cc: Clark Williams <williams@redhat.com>
Link: https://lore.kernel.org/20250305140406.350227-9-gmonaco@redhat.com
Signed-off-by: Gabriele Monaco <gmonaco@redhat.com>
Signed-off-by: Steven Rostedt (Google) <rostedt@goodmis.org>
2025-03-24 17:27:40 -04:00
James Clark
4a29fa2626 coresight: docs: Remove target sink from examples
Previously the sink had to be specified, but now it auto selects one by
default. Including a sink in the examples causes issues when copy
pasting the command because it might not work if that sink isn't
present. Remove the sink from all the basic examples and create a new
section specifically about overriding the default one.

Make the text a but more concise now that it's in the advanced section,
and similarly for removing the old kernel advice.

Signed-off-by: James Clark <james.clark@linaro.org>
Reviewed-by: Leo Yan <leo.yan@arm.com>
Signed-off-by: Suzuki K Poulose <suzuki.poulose@arm.com>
Link: https://lore.kernel.org/r/20241210144933.295798-1-james.clark@linaro.org
2025-03-11 14:55:57 +00:00
Linu Cherian
b47d1fcd0d Documentation: coresight: Panic support
Add documentation on using coresight during panic
and watchdog.

Signed-off-by: Linu Cherian <lcherian@marvell.com>
Signed-off-by: Suzuki K Poulose <suzuki.poulose@arm.com>
Link: https://lore.kernel.org/r/20250212114918.548431-9-lcherian@marvell.com
2025-02-21 16:17:40 +00:00
Mauro Carvalho Chehab
6a0c4b61e1 docs: trace: decode_msr.py: make it compatible with python 3
This script uses print <foo> instead of print(foo), which is
incompatible with Python 3.

Fix it.

Signed-off-by: Mauro Carvalho Chehab <mchehab+huawei@kernel.org>
Link: https://lore.kernel.org/r/88bb0d47100feaa3cda215e68bf6500dc67da7b3.1739257245.git.mchehab+huawei@kernel.org
Signed-off-by: Jonathan Corbet <corbet@lwn.net>
2025-02-13 09:45:22 -07:00
Linus Torvalds
e8744fbc83 tracing updates for v6.14:
- Cleanup with guard() and free() helpers
 
   There were several places in the code that had a lot of "goto out" in the
   error paths to either unlock a lock or free some memory that was
   allocated. But this is error prone. Convert the code over to use the
   guard() and free() helpers that let the compiler unlock locks or free
   memory when the function exits.
 
 - Update the Rust tracepoint code to use the C code too
 
   There was some duplication of the tracepoint code for Rust that did the
   same logic as the C code. Add a helper that makes it possible for both
   algorithms to use the same logic in one place.
 
 - Add poll to trace event hist files
 
   It is useful to know when an event is triggered, or even with some
   filtering. Since hist files of events get updated when active and the
   event is triggered, allow applications to poll the hist file and wake up
   when an event is triggered. This will let the application know that the
   event it is waiting for happened.
 
 - Add :mod: command to enable events for current or future modules
 
   The function tracer already has a way to enable functions to be traced in
   modules by writing ":mod:<module>" into set_ftrace_filter. That will
   enable either all the functions for the module if it is loaded, or if it
   is not, it will cache that command, and when the module is loaded that
   matches <module>, its functions will be enabled. This also allows init
   functions to be traced. But currently events do not have that feature.
 
   Add the command where if ':mod:<module>' is written into set_event, then
   either all the modules events are enabled if it is loaded, or cache it so
   that the module's events are enabled when it is loaded. This also works
   from the kernel command line, where "trace_event=:mod:<module>", when the
   module is loaded at boot up, its events will be enabled then.
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Merge tag 'trace-v6.14-3' of git://git.kernel.org/pub/scm/linux/kernel/git/trace/linux-trace

Pull tracing updates from Steven Rostedt:

 - Cleanup with guard() and free() helpers

   There were several places in the code that had a lot of "goto out" in
   the error paths to either unlock a lock or free some memory that was
   allocated. But this is error prone. Convert the code over to use the
   guard() and free() helpers that let the compiler unlock locks or free
   memory when the function exits.

 - Update the Rust tracepoint code to use the C code too

   There was some duplication of the tracepoint code for Rust that did
   the same logic as the C code. Add a helper that makes it possible for
   both algorithms to use the same logic in one place.

 - Add poll to trace event hist files

   It is useful to know when an event is triggered, or even with some
   filtering. Since hist files of events get updated when active and the
   event is triggered, allow applications to poll the hist file and wake
   up when an event is triggered. This will let the application know
   that the event it is waiting for happened.

 - Add :mod: command to enable events for current or future modules

   The function tracer already has a way to enable functions to be
   traced in modules by writing ":mod:<module>" into set_ftrace_filter.
   That will enable either all the functions for the module if it is
   loaded, or if it is not, it will cache that command, and when the
   module is loaded that matches <module>, its functions will be
   enabled. This also allows init functions to be traced. But currently
   events do not have that feature.

   Add the command where if ':mod:<module>' is written into set_event,
   then either all the modules events are enabled if it is loaded, or
   cache it so that the module's events are enabled when it is loaded.
   This also works from the kernel command line, where
   "trace_event=:mod:<module>", when the module is loaded at boot up,
   its events will be enabled then.

* tag 'trace-v6.14-3' of git://git.kernel.org/pub/scm/linux/kernel/git/trace/linux-trace: (26 commits)
  tracing: Fix output of set_event for some cached module events
  tracing: Fix allocation of printing set_event file content
  tracing: Rename update_cache() to update_mod_cache()
  tracing: Fix #if CONFIG_MODULES to #ifdef CONFIG_MODULES
  selftests/ftrace: Add test that tests event :mod: commands
  tracing: Cache ":mod:" events for modules not loaded yet
  tracing: Add :mod: command to enabled module events
  selftests/tracing: Add hist poll() support test
  tracing/hist: Support POLLPRI event for poll on histogram
  tracing/hist: Add poll(POLLIN) support on hist file
  tracing: Fix using ret variable in tracing_set_tracer()
  tracepoint: Reduce duplication of __DO_TRACE_CALL
  tracing/string: Create and use __free(argv_free) in trace_dynevent.c
  tracing: Switch trace_stat.c code over to use guard()
  tracing: Switch trace_stack.c code over to use guard()
  tracing: Switch trace_osnoise.c code over to use guard() and __free()
  tracing: Switch trace_events_synth.c code over to use guard()
  tracing: Switch trace_events_filter.c code over to use guard()
  tracing: Switch trace_events_trigger.c code over to use guard()
  tracing: Switch trace_events_hist.c code over to use guard()
  ...
2025-01-23 17:51:16 -08:00
Linus Torvalds
d0f93ac2c3 Documentation changes this time around include:
- Quite a bit of Chinese and Spanish translation work.
 
 - Clarifying that Git commit IDs >12chars are OK
 
 - A new nvme-multipath document
 
 - A reorganization of the admin-guide top-level page to make it readable
 
 - Clarification of the role of Acked-by and maintainer discretion on their
   acceptance.
 
 - Some reorganization of debugging-oriented docs.
 
 ...and typo fixes, documentation updates, etc. as usual.
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Merge tag 'docs-6.14' of git://git.lwn.net/linux

Pull Documentation updates from Jonathan Corbet:

 - Quite a bit of Chinese and Spanish translation work

 - Clarifying that Git commit IDs >12chars are OK

 - A new nvme-multipath document

 - A reorganization of the admin-guide top-level page to make it
   readable

 - Clarification of the role of Acked-by and maintainer discretion on
   their acceptance

 - Some reorganization of debugging-oriented docs

... and typo fixes, documentation updates, etc as usual

* tag 'docs-6.14' of git://git.lwn.net/linux: (50 commits)
  Documentation: Fix x86_64 UEFI outdated references to elilo
  Documentation/sysctl: Add timer_migration to kernel.rst
  docs/mm: Physical memory: Remove zone_t
  docs: submitting-patches: clarify that signers may use their discretion on tags
  docs: submitting-patches: clarify difference between Acked-by and Reviewed-by
  docs: submitting-patches: clarify Acked-by and introduce "# Suffix"
  Documentation: bug-hunting.rst: remove odd contact information
  docs/zh_CN: Add sak index Chinese translation
  doc: module: DEFAULT_SYMBOL_NAMESPACE must be defined before #includes
  doc: module: Fix documented type of namespace
  Documentation/kernel-parameters: Fix a reference to vga-softcursor.rst
  docs/zh_CN: Add landlock index Chinese translation
  Documentation: Fix typo localmodonfig -> localmodconfig
  overlayfs.rst: Fix and improve grammar
  docs/zh_CN: Add siphash index Chinese translation
  docs/zh_CN: Add security IMA-templates Chinese translation
  docs/zh_CN: Add security digsig Chinese translation
  Align git commit ID abbreviation guidelines and checks
  docs: process: submitting-patches: split canonical patch format section
  docs/zh_CN: Add security lsm Chinese translation
  ...
2025-01-21 18:00:00 -08:00
Linus Torvalds
2e04247f7c ftrace updates for v6.14:
- Have fprobes built on top of function graph infrastructure
 
   The fprobe logic is an optimized kprobe that uses ftrace to attach to
   functions when a probe is needed at the start or end of the function. The
   fprobe and kretprobe logic implements a similar method as the function
   graph tracer to trace the end of the function. That is to hijack the
   return address and jump to a trampoline to do the trace when the function
   exits. To do this, a shadow stack needs to be created to store the
   original return address.  Fprobes and function graph do this slightly
   differently. Fprobes (and kretprobes) has slots per callsite that are
   reserved to save the return address. This is fine when just a few points
   are traced. But users of fprobes, such as BPF programs, are starting to add
   many more locations, and this method does not scale.
 
   The function graph tracer was created to trace all functions in the
   kernel. In order to do this, when function graph tracing is started, every
   task gets its own shadow stack to hold the return address that is going to
   be traced. The function graph tracer has been updated to allow multiple
   users to use its infrastructure. Now have fprobes be one of those users.
   This will also allow for the fprobe and kretprobe methods to trace the
   return address to become obsolete. With new technologies like CFI that
   need to know about these methods of hijacking the return address, going
   toward a solution that has only one method of doing this will make the
   kernel less complex.
 
 - Cleanup with guard() and free() helpers
 
   There were several places in the code that had a lot of "goto out" in the
   error paths to either unlock a lock or free some memory that was
   allocated. But this is error prone. Convert the code over to use the
   guard() and free() helpers that let the compiler unlock locks or free
   memory when the function exits.
 
 - Remove disabling of interrupts in the function graph tracer
 
   When function graph tracer was first introduced, it could race with
   interrupts and NMIs. To prevent that race, it would disable interrupts and
   not trace NMIs. But the code has changed to allow NMIs and also
   interrupts. This change was done a long time ago, but the disabling of
   interrupts was never removed. Remove the disabling of interrupts in the
   function graph tracer is it is not needed. This greatly improves its
   performance.
 
 - Allow the :mod: command to enable tracing module functions on the kernel
   command line.
 
   The function tracer already has a way to enable functions to be traced in
   modules by writing ":mod:<module>" into set_ftrace_filter. That will
   enable either all the functions for the module if it is loaded, or if it
   is not, it will cache that command, and when the module is loaded that
   matches <module>, its functions will be enabled. This also allows init
   functions to be traced. But currently events do not have that feature.
 
   Because enabling function tracing can be done very early at boot up
   (before scheduling is enabled), the commands that can be done when
   function tracing is started is limited. Having the ":mod:" command to
   trace module functions as they are loaded is very useful. Update the
   kernel command line function filtering to allow it.
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Merge tag 'ftrace-v6.14' of git://git.kernel.org/pub/scm/linux/kernel/git/trace/linux-trace

Pull ftrace updates from Steven Rostedt:

 - Have fprobes built on top of function graph infrastructure

   The fprobe logic is an optimized kprobe that uses ftrace to attach to
   functions when a probe is needed at the start or end of the function.
   The fprobe and kretprobe logic implements a similar method as the
   function graph tracer to trace the end of the function. That is to
   hijack the return address and jump to a trampoline to do the trace
   when the function exits. To do this, a shadow stack needs to be
   created to store the original return address. Fprobes and function
   graph do this slightly differently. Fprobes (and kretprobes) has
   slots per callsite that are reserved to save the return address. This
   is fine when just a few points are traced. But users of fprobes, such
   as BPF programs, are starting to add many more locations, and this
   method does not scale.

   The function graph tracer was created to trace all functions in the
   kernel. In order to do this, when function graph tracing is started,
   every task gets its own shadow stack to hold the return address that
   is going to be traced. The function graph tracer has been updated to
   allow multiple users to use its infrastructure. Now have fprobes be
   one of those users. This will also allow for the fprobe and kretprobe
   methods to trace the return address to become obsolete. With new
   technologies like CFI that need to know about these methods of
   hijacking the return address, going toward a solution that has only
   one method of doing this will make the kernel less complex.

 - Cleanup with guard() and free() helpers

   There were several places in the code that had a lot of "goto out" in
   the error paths to either unlock a lock or free some memory that was
   allocated. But this is error prone. Convert the code over to use the
   guard() and free() helpers that let the compiler unlock locks or free
   memory when the function exits.

 - Remove disabling of interrupts in the function graph tracer

   When function graph tracer was first introduced, it could race with
   interrupts and NMIs. To prevent that race, it would disable
   interrupts and not trace NMIs. But the code has changed to allow NMIs
   and also interrupts. This change was done a long time ago, but the
   disabling of interrupts was never removed. Remove the disabling of
   interrupts in the function graph tracer is it is not needed. This
   greatly improves its performance.

 - Allow the :mod: command to enable tracing module functions on the
   kernel command line.

   The function tracer already has a way to enable functions to be
   traced in modules by writing ":mod:<module>" into set_ftrace_filter.
   That will enable either all the functions for the module if it is
   loaded, or if it is not, it will cache that command, and when the
   module is loaded that matches <module>, its functions will be
   enabled. This also allows init functions to be traced. But currently
   events do not have that feature.

   Because enabling function tracing can be done very early at boot up
   (before scheduling is enabled), the commands that can be done when
   function tracing is started is limited. Having the ":mod:" command to
   trace module functions as they are loaded is very useful. Update the
   kernel command line function filtering to allow it.

* tag 'ftrace-v6.14' of git://git.kernel.org/pub/scm/linux/kernel/git/trace/linux-trace: (26 commits)
  ftrace: Implement :mod: cache filtering on kernel command line
  tracing: Adopt __free() and guard() for trace_fprobe.c
  bpf: Use ftrace_get_symaddr() for kprobe_multi probes
  ftrace: Add ftrace_get_symaddr to convert fentry_ip to symaddr
  Documentation: probes: Update fprobe on function-graph tracer
  selftests/ftrace: Add a test case for repeating register/unregister fprobe
  selftests: ftrace: Remove obsolate maxactive syntax check
  tracing/fprobe: Remove nr_maxactive from fprobe
  fprobe: Add fprobe_header encoding feature
  fprobe: Rewrite fprobe on function-graph tracer
  s390/tracing: Enable HAVE_FTRACE_GRAPH_FUNC
  ftrace: Add CONFIG_HAVE_FTRACE_GRAPH_FUNC
  bpf: Enable kprobe_multi feature if CONFIG_FPROBE is enabled
  tracing/fprobe: Enable fprobe events with CONFIG_DYNAMIC_FTRACE_WITH_ARGS
  tracing: Add ftrace_fill_perf_regs() for perf event
  tracing: Add ftrace_partial_regs() for converting ftrace_regs to pt_regs
  fprobe: Use ftrace_regs in fprobe exit handler
  fprobe: Use ftrace_regs in fprobe entry handler
  fgraph: Pass ftrace_regs to retfunc
  fgraph: Replace fgraph_ret_regs with ftrace_regs
  ...
2025-01-21 15:15:28 -08:00
Steven Rostedt
b355247df1 tracing: Cache ":mod:" events for modules not loaded yet
When the :mod: command is written into /sys/kernel/tracing/set_event (or
that file within an instance), if the module specified after the ":mod:"
is not yet loaded, it will store that string internally. When the module
is loaded, it will enable the events as if the module was loaded when the
string was written into the set_event file.

This can also be useful to enable events that are in the init section of
the module, as the events are enabled before the init section is executed.

This also works on the kernel command line:

 trace_event=:mod:<module>

Will enable the events for <module> when it is loaded.

Cc: Masami Hiramatsu <mhiramat@kernel.org>
Cc: Mark Rutland <mark.rutland@arm.com>
Cc: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
Cc: Andrew Morton <akpm@linux-foundation.org>
Link: https://lore.kernel.org/20250116143533.514730995@goodmis.org
Signed-off-by: Steven Rostedt (Google) <rostedt@goodmis.org>
2025-01-16 09:41:08 -05:00
Steven Rostedt
4c86bc531e tracing: Add :mod: command to enabled module events
Add a :mod: command to enable only events from a given module from the
set_events file.

  echo '*:mod:<module>' > set_events

Or

  echo ':mod:<module>' > set_events

Will enable all events for that module. Specific events can also be
enabled via:

  echo '<event>:mod:<module>' > set_events

Or

  echo '<system>:<event>:mod:<module>' > set_events

Or

  echo '*:<event>:mod:<module>' > set_events

The ":mod:" keyword is consistent with the function tracing filter to
enable functions from a given module.

Cc: Masami Hiramatsu <mhiramat@kernel.org>
Cc: Mark Rutland <mark.rutland@arm.com>
Cc: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
Cc: Andrew Morton <akpm@linux-foundation.org>
Link: https://lore.kernel.org/20250116143533.214496360@goodmis.org
Signed-off-by: Steven Rostedt (Google) <rostedt@goodmis.org>
2025-01-16 09:41:07 -05:00
Steven Rostedt
94d529a325 ftrace: Document that multiple function_graph tracing may have different times
The function graph tracer now calculates the calltime internally and for
each instance. If there are two instances that are running function graph
tracer and are tracing the same functions, the timings of the length of
those functions may be slightly different:

 # trace-cmd record -B foo -p function_graph -B bar -p function_graph sleep 5
 # trace-cmd report
[..]
bar:            sleep-981   [000] ...1.  1101.109027: funcgraph_entry:        0.764 us   |          mutex_unlock(); (ret=0xffff8abcc256c300)
foo:            sleep-981   [000] ...1.  1101.109028: funcgraph_entry:        0.748 us   |          mutex_unlock(); (ret=0xffff8abcc256c300)
bar:            sleep-981   [000] .....  1101.109029: funcgraph_exit:         2.456 us   |        } (ret=0xffff8abcc256c300)
foo:            sleep-981   [000] .....  1101.109029: funcgraph_exit:         2.403 us   |        } (ret=0xffff8abcc256c300)
bar:            sleep-981   [000] d..1.  1101.109031: funcgraph_entry:        0.844 us   |  fpregs_assert_state_consistent(); (ret=0x0)
foo:            sleep-981   [000] d..1.  1101.109032: funcgraph_entry:        0.803 us   |  fpregs_assert_state_consistent(); (ret=0x0)

Link: https://lore.kernel.org/all/20250114101806.b2778cb01f34f5be9d23ad98@kernel.org/

Cc: Mark Rutland <mark.rutland@arm.com>
Cc: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
Suggested-by: Masami Hiramatsu <mhiramat@kernel.org>
Link: https://lore.kernel.org/20250114101202.02e7bc68@gandalf.local.home
Signed-off-by: Steven Rostedt (Google) <rostedt@goodmis.org>
2025-01-14 10:45:24 -05:00
Masami Hiramatsu (Google)
54b6b4a3d4 Documentation: probes: Update fprobe on function-graph tracer
Update fprobe documentation for the new fprobe on function-graph
tracer. This includes some bahvior changes and pt_regs to
ftrace_regs interface change.

Cc: Alexei Starovoitov <alexei.starovoitov@gmail.com>
Cc: Florent Revest <revest@chromium.org>
Cc: Martin KaFai Lau <martin.lau@linux.dev>
Cc: bpf <bpf@vger.kernel.org>
Cc: Alexei Starovoitov <ast@kernel.org>
Cc: Jiri Olsa <jolsa@kernel.org>
Cc: Alan Maguire <alan.maguire@oracle.com>
Cc: Mark Rutland <mark.rutland@arm.com>
Link: https://lore.kernel.org/173519010442.391279.10732749889346824783.stgit@devnote2
Signed-off-by: Masami Hiramatsu (Google) <mhiramat@kernel.org>
Signed-off-by: Steven Rostedt (Google) <rostedt@goodmis.org>
2024-12-26 10:50:06 -05:00
Andrew Kreimer
09cbeb5b30 Documentation/rv: Fix typos
There are some typos in the documentation: 'a' -> 'at', missing 'to'.
Fix them.

Signed-off-by: Andrew Kreimer <algonell@gmail.com>
Acked-by: Steven Rostedt (Google) <rostedt@goodmis.org>
Signed-off-by: Jonathan Corbet <corbet@lwn.net>
Link: https://lore.kernel.org/r/20241209130640.10954-1-algonell@gmail.com
2024-12-13 08:42:23 -07:00
Thomas Gleixner
0172afefbf tracing: Record task flag NEED_RESCHED_LAZY.
The scheduler added NEED_RESCHED_LAZY scheduling. Record this state as
part of trace flags and expose it in the need_resched field.

Record and expose NEED_RESCHED_LAZY.

[bigeasy: Commit description, documentation bits.]

Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Masami Hiramatsu <mhiramat@kernel.org>
Cc: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
Link: https://lore.kernel.org/20241122202849.7DfYpJR0@linutronix.de
Reviewed-by: Ankur Arora <ankur.a.arora@oracle.com>
Reviewed-by: Steven Rostedt (Google) <rostedt@goodmis.org>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
Signed-off-by: Steven Rostedt (Google) <rostedt@goodmis.org>
2024-11-22 17:49:39 -05:00
Linus Torvalds
06afb0f361 tracing updates for v6.13:
- Addition of faultable tracepoints
 
   There's a tracepoint attached to both a system call entry and exit. This
   location is known to allow page faults. The tracepoints are called under
   an rcu_read_lock() which does not allow faults that can sleep. This limits
   the ability of tracepoint handlers to page fault in user space system call
   parameters. Now these tracepoints have been made "faultable", allowing the
   callbacks to fault in user space parameters and record them.
 
   Note, only the infrastructure has been implemented. The consumers (perf,
   ftrace, BPF) now need to have their code modified to allow faults.
 
 - Fix up of BPF code for the tracepoint faultable logic
 
 - Update tracepoints to use the new static branch API
 
 - Remove trace_*_rcuidle() variants and the SRCU protection they used
 
 - Remove unused TRACE_EVENT_FL_FILTERED logic
 
 - Replace strncpy() with strscpy() and memcpy()
 
 - Use replace per_cpu_ptr(smp_processor_id()) with this_cpu_ptr()
 
 - Fix perf events to not duplicate samples when tracing is enabled
 
 - Replace atomic64_add_return(1, counter) with atomic64_inc_return(counter)
 
 - Make stack trace buffer 4K instead of PAGE_SIZE
 
 - Remove TRACE_FLAG_IRQS_NOSUPPORT flag as it was never used
 
 - Get the true return address for function tracer when function graph tracer
   is also running.
 
   When function_graph trace is running along with function tracer,
   the parent function of the function tracer sometimes is
   "return_to_handler", which is the function graph trampoline to record
   the exit of the function. Use existing logic that calls into the
   fgraph infrastructure to find the real return address.
 
 - Remove (un)regfunc pointers out of tracepoint structure
 
 - Added last minute bug fix for setting pending modules in stack function
   filter.
 
   echo "write*:mod:ext3" > /sys/kernel/tracing/stack_trace_filter
 
   Would cause a kernel NULL dereference.
 
 - Minor clean ups
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Merge tag 'trace-v6.13' of git://git.kernel.org/pub/scm/linux/kernel/git/trace/linux-trace

Pull tracing updates from Steven Rostedt:

 - Addition of faultable tracepoints

   There's a tracepoint attached to both a system call entry and exit.
   This location is known to allow page faults. The tracepoints are
   called under an rcu_read_lock() which does not allow faults that can
   sleep. This limits the ability of tracepoint handlers to page fault
   in user space system call parameters. Now these tracepoints have been
   made "faultable", allowing the callbacks to fault in user space
   parameters and record them.

   Note, only the infrastructure has been implemented. The consumers
   (perf, ftrace, BPF) now need to have their code modified to allow
   faults.

 - Fix up of BPF code for the tracepoint faultable logic

 - Update tracepoints to use the new static branch API

 - Remove trace_*_rcuidle() variants and the SRCU protection they used

 - Remove unused TRACE_EVENT_FL_FILTERED logic

 - Replace strncpy() with strscpy() and memcpy()

 - Use replace per_cpu_ptr(smp_processor_id()) with this_cpu_ptr()

 - Fix perf events to not duplicate samples when tracing is enabled

 - Replace atomic64_add_return(1, counter) with
   atomic64_inc_return(counter)

 - Make stack trace buffer 4K instead of PAGE_SIZE

 - Remove TRACE_FLAG_IRQS_NOSUPPORT flag as it was never used

 - Get the true return address for function tracer when function graph
   tracer is also running.

   When function_graph trace is running along with function tracer, the
   parent function of the function tracer sometimes is
   "return_to_handler", which is the function graph trampoline to record
   the exit of the function. Use existing logic that calls into the
   fgraph infrastructure to find the real return address.

 - Remove (un)regfunc pointers out of tracepoint structure

 - Added last minute bug fix for setting pending modules in stack
   function filter.

     echo "write*:mod:ext3" > /sys/kernel/tracing/stack_trace_filter

   Would cause a kernel NULL dereference.

 - Minor clean ups

* tag 'trace-v6.13' of git://git.kernel.org/pub/scm/linux/kernel/git/trace/linux-trace: (31 commits)
  ftrace: Fix regression with module command in stack_trace_filter
  tracing: Fix function name for trampoline
  ftrace: Get the true parent ip for function tracer
  tracing: Remove redundant check on field->field in histograms
  bpf: ensure RCU Tasks Trace GP for sleepable raw tracepoint BPF links
  bpf: decouple BPF link/attach hook and BPF program sleepable semantics
  bpf: put bpf_link's program when link is safe to be deallocated
  tracing: Replace strncpy() with strscpy() when copying comm
  tracing: Add might_fault() check in __DECLARE_TRACE_SYSCALL
  tracing: Fix syscall tracepoint use-after-free
  tracing: Introduce tracepoint_is_faultable()
  tracing: Introduce tracepoint extended structure
  tracing: Remove TRACE_FLAG_IRQS_NOSUPPORT
  tracing: Replace multiple deprecated strncpy with memcpy
  tracing: Make percpu stack trace buffer invariant to PAGE_SIZE
  tracing: Use atomic64_inc_return() in trace_clock_counter()
  trace/trace_event_perf: remove duplicate samples on the first tracepoint event
  tracing/bpf: Add might_fault check to syscall probes
  tracing/perf: Add might_fault check to syscall probes
  tracing/ftrace: Add might_fault check to syscall probes
  ...
2024-11-22 13:27:01 -08:00
Sebastian Andrzej Siewior
e9f0a36347 tracing: Remove TRACE_FLAG_IRQS_NOSUPPORT
It was possible to enable tracing with no IRQ tracing support. The
tracing infrastructure would then record TRACE_FLAG_IRQS_NOSUPPORT as
the only tracing flag and show an 'X' in the output.

The last user of this feature was PPC32 which managed to implement it
during PowerPC merge in 2009. Since then, it was unused and the PPC32
dependency was finally removed in commit 0ea5ee0351 ("tracing: Remove
PPC32 wart from config TRACING_SUPPORT").
Since the PowerPC merge the code behind !CONFIG_TRACE_IRQFLAGS_SUPPORT
with TRACING enabled can no longer be selected used and the 'X' is not
displayed or recorded.

Remove the CONFIG_TRACE_IRQFLAGS_SUPPORT from the tracing code. Remove
TRACE_FLAG_IRQS_NOSUPPORT.

Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Masami Hiramatsu <mhiramat@kernel.org>
Cc: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
Link: https://lore.kernel.org/20241022110112.XJI8I9T2@linutronix.de
Signed-off-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
Signed-off-by: Steven Rostedt (Google) <rostedt@goodmis.org>
2024-11-01 14:37:30 -04:00
SurajSonawane2415
998bece1d2 docs: fix WARNING document not included in any toctree
Add debugging.rst to the relevant toctree to fix warning
about missing documentation inclusion in toctree.

Signed-off-by: SurajSonawane2415 <surajsonawane0215@gmail.com>
Signed-off-by: Jonathan Corbet <corbet@lwn.net>
Link: https://lore.kernel.org/r/20241002195817.22972-1-surajsonawane0215@gmail.com
2024-10-07 11:50:54 -06:00
Gabriele Monaco
11786d64b6 tracing: doc: Fix typo in ftrace histogram
The Tracing > Histogram page contains a typo in the field display
modifiers table.

Signed-off-by: Gabriele Monaco <gmonaco@redhat.com>
Acked-by: Steven Rostedt (Google) <rostedt@goodmis.org>
Signed-off-by: Jonathan Corbet <corbet@lwn.net>
Link: https://lore.kernel.org/r/20241003122334.44682-2-gmonaco@redhat.com
2024-10-07 11:50:54 -06:00
Steven Rostedt
2fcd5aff92 tracing/Documentation: Start a document on how to debug with tracing
Add a new document Documentation/trace/debugging.rst that will hold
various ways to debug tracing.

This initial version mentions trace_printk and how to create persistent
buffers that can last across bootups.

Cc: Masami Hiramatsu <mhiramat@kernel.org>
Cc: Mark Rutland <mark.rutland@arm.com>
Cc: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: Vincent Donnefort <vdonnefort@google.com>
Cc: Joel Fernandes <joel@joelfernandes.org>
Cc: Ingo Molnar <mingo@kernel.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Vineeth Pillai <vineeth@bitbyteword.org>
Cc: Beau Belgrave <beaub@linux.microsoft.com>
Cc: Alexander Graf <graf@amazon.com>
Cc: Baoquan He <bhe@redhat.com>
Cc: Borislav Petkov <bp@alien8.de>
Cc: "Paul E. McKenney" <paulmck@kernel.org>
Cc: David Howells <dhowells@redhat.com>
Cc: Mike Rapoport <rppt@kernel.org>
Cc: Dave Hansen <dave.hansen@linux.intel.com>
Cc: Tony Luck <tony.luck@intel.com>
Cc: Guenter Roeck <linux@roeck-us.net>
Cc: Ross Zwisler <zwisler@google.com>
Cc: Kees Cook <keescook@chromium.org>
Cc: Alexander Aring <aahringo@redhat.com>
Cc: "Luis Claudio R. Goncalves" <lgoncalv@redhat.com>
Cc: Tomas Glozar <tglozar@redhat.com>
Cc: John Kacur <jkacur@redhat.com>
Cc: Clark Williams <williams@redhat.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: "Jonathan Corbet" <corbet@lwn.net>
Link: https://lore.kernel.org/20240823014019.702433486@goodmis.org
Signed-off-by: Steven Rostedt (Google) <rostedt@goodmis.org>
2024-08-26 13:54:08 -04:00
Steven Rostedt
ef2bd81d0c tracing: Add option to set an instance to be the trace_printk destination
Add a option "trace_printk_dest" that will make the tracing instance the
location that trace_printk() will go to. This is useful if the
trace_printk or one of the top level tracers is too noisy and there's a
need to separate the two. Then an instance can be created, the
trace_printk can be set to go there instead, where it will not be lost in
the noise of the top level tracer.

Note, only one instance can be the destination of trace_printk at a time.
If an instance sets this flag, the instance that had it set will have it
cleared. There is always one instance that has this set. By default, that
is the top instance. This flag cannot be cleared from the top instance.
Doing so will result in an -EINVAL. The only way this flag can be cleared
from the top instance is by another instance setting it.

Cc: Masami Hiramatsu <mhiramat@kernel.org>
Cc: Mark Rutland <mark.rutland@arm.com>
Cc: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: Vincent Donnefort <vdonnefort@google.com>
Cc: Joel Fernandes <joel@joelfernandes.org>
Cc: Ingo Molnar <mingo@kernel.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Vineeth Pillai <vineeth@bitbyteword.org>
Cc: Beau Belgrave <beaub@linux.microsoft.com>
Cc: Alexander Graf <graf@amazon.com>
Cc: Baoquan He <bhe@redhat.com>
Cc: Borislav Petkov <bp@alien8.de>
Cc: "Paul E. McKenney" <paulmck@kernel.org>
Cc: David Howells <dhowells@redhat.com>
Cc: Mike Rapoport <rppt@kernel.org>
Cc: Dave Hansen <dave.hansen@linux.intel.com>
Cc: Tony Luck <tony.luck@intel.com>
Cc: Guenter Roeck <linux@roeck-us.net>
Cc: Ross Zwisler <zwisler@google.com>
Cc: Kees Cook <keescook@chromium.org>
Cc: Alexander Aring <aahringo@redhat.com>
Cc: "Luis Claudio R. Goncalves" <lgoncalv@redhat.com>
Cc: Tomas Glozar <tglozar@redhat.com>
Cc: John Kacur <jkacur@redhat.com>
Cc: Clark Williams <williams@redhat.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: "Jonathan Corbet" <corbet@lwn.net>
Link: https://lore.kernel.org/20240823014019.545459018@goodmis.org
Signed-off-by: Steven Rostedt (Google) <rostedt@goodmis.org>
2024-08-26 13:54:08 -04:00
Linus Torvalds
70045bfc4c ftrace: Rewrite of function graph tracer
Up until now, the function graph tracer could only have a single user
 attached to it. If another user tried to attach to the function graph
 tracer while one was already attached, it would fail. Allowing function
 graph tracer to have more than one user has been asked for since 2009, but
 it required a rewrite to the logic to pull it off so it never happened.
 Until now!
 
 There's three systems that trace the return of a function. That is
 kretprobes, function graph tracer, and BPF. kretprobes and function graph
 tracing both do it similarly. The difference is that kretprobes uses a
 shadow stack per callback and function graph tracer creates a shadow stack
 for all tasks. The function graph tracer method makes it possible to trace
 the return of all functions. As kretprobes now needs that feature too,
 allowing it to use function graph tracer was needed. BPF also wants to
 trace the return of many probes and its method doesn't scale either.
 Having it use function graph tracer would improve that.
 
 By allowing function graph tracer to have multiple users allows both
 kretprobes and BPF to use function graph tracer in these cases. This will
 allow kretprobes code to be removed in the future as it's version will no
 longer be needed. Note, function graph tracer is only limited to 16
 simultaneous users, due to shadow stack size and allocated slots.
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Merge tag 'ftrace-v6.11' of git://git.kernel.org/pub/scm/linux/kernel/git/trace/linux-trace

Pull ftrace updates from Steven Rostedt:
 "Rewrite of function graph tracer to allow multiple users

  Up until now, the function graph tracer could only have a single user
  attached to it. If another user tried to attach to the function graph
  tracer while one was already attached, it would fail. Allowing
  function graph tracer to have more than one user has been asked for
  since 2009, but it required a rewrite to the logic to pull it off so
  it never happened. Until now!

  There's three systems that trace the return of a function. That is
  kretprobes, function graph tracer, and BPF. kretprobes and function
  graph tracing both do it similarly. The difference is that kretprobes
  uses a shadow stack per callback and function graph tracer creates a
  shadow stack for all tasks. The function graph tracer method makes it
  possible to trace the return of all functions. As kretprobes now needs
  that feature too, allowing it to use function graph tracer was needed.
  BPF also wants to trace the return of many probes and its method
  doesn't scale either. Having it use function graph tracer would
  improve that.

  By allowing function graph tracer to have multiple users allows both
  kretprobes and BPF to use function graph tracer in these cases. This
  will allow kretprobes code to be removed in the future as it's version
  will no longer be needed.

  Note, function graph tracer is only limited to 16 simultaneous users,
  due to shadow stack size and allocated slots"

* tag 'ftrace-v6.11' of git://git.kernel.org/pub/scm/linux/kernel/git/trace/linux-trace: (49 commits)
  fgraph: Use str_plural() in test_graph_storage_single()
  function_graph: Add READ_ONCE() when accessing fgraph_array[]
  ftrace: Add missing kerneldoc parameters to unregister_ftrace_direct()
  function_graph: Everyone uses HAVE_FUNCTION_GRAPH_RET_ADDR_PTR, remove it
  function_graph: Fix up ftrace_graph_ret_addr()
  function_graph: Make fgraph_update_pid_func() a stub for !DYNAMIC_FTRACE
  function_graph: Rename BYTE_NUMBER to CHAR_NUMBER in selftests
  fgraph: Remove some unused functions
  ftrace: Hide one more entry in stack trace when ftrace_pid is enabled
  function_graph: Do not update pid func if CONFIG_DYNAMIC_FTRACE not enabled
  function_graph: Make fgraph_do_direct static key static
  ftrace: Fix prototypes for ftrace_startup/shutdown_subops()
  ftrace: Assign RCU list variable with rcu_assign_ptr()
  ftrace: Assign ftrace_list_end to ftrace_ops_list type cast to RCU
  ftrace: Declare function_trace_op in header to quiet sparse warning
  ftrace: Add comments to ftrace_hash_move() and friends
  ftrace: Convert "inc" parameter to bool in ftrace_hash_rec_update_modify()
  ftrace: Add comments to ftrace_hash_rec_disable/enable()
  ftrace: Remove "filter_hash" parameter from __ftrace_hash_rec_update()
  ftrace: Rename dup_hash() and comment it
  ...
2024-07-18 13:36:33 -07:00
Luis Claudio R. Goncalves
c40583e19e rtla/osnoise: set the default threshold to 1us
Change the default threshold for osnoise to 1us, so that any noise
equal or above this value is recorded. Let the user set a higher
threshold if necessary.

Link: https://lore.kernel.org/linux-trace-kernel/Zmb-QhiiiI6jM9To@uudg.org

Cc: Masami Hiramatsu <mhiramat@kernel.org>
Cc: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
Cc: Jonathan Corbet <corbet@lwn.net>
Suggested-by: Daniel Bristot de Oliveira <bristot@kernel.org>
Reviewed-by: Clark Williams <williams@redhat.com>
Signed-off-by: Luis Claudio R. Goncalves <lgoncalv@redhat.com>
Acked-by: Daniel Bristot de Oliveira <bristot@kernel.org>
Signed-off-by: Steven Rostedt (Google) <rostedt@goodmis.org>
2024-07-01 18:54:31 -04:00
Steven Rostedt (Google)
5f7fb89a11 function_graph: Everyone uses HAVE_FUNCTION_GRAPH_RET_ADDR_PTR, remove it
All architectures that implement function graph also implements
HAVE_FUNCTION_GRAPH_RET_ADDR_PTR. Remove it, as it is no longer a
differentiator.

Link: https://lore.kernel.org/linux-trace-kernel/20240611031737.982047614@goodmis.org

Cc: Masami Hiramatsu <mhiramat@kernel.org>
Cc: Mark Rutland <mark.rutland@arm.com>
Cc: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
Cc: Jonathan Corbet <corbet@lwn.net>
Cc: Catalin Marinas <catalin.marinas@arm.com>
Cc: Will Deacon <will@kernel.org>
Cc: Guo Ren <guoren@kernel.org>
Cc: Huacai Chen <chenhuacai@kernel.org>
Cc: WANG Xuerui <kernel@xen0n.name>
Cc: Michael Ellerman <mpe@ellerman.id.au>
Cc: Nicholas Piggin <npiggin@gmail.com>
Cc: Christophe Leroy <christophe.leroy@csgroup.eu>
Cc: "Naveen N. Rao" <naveen.n.rao@linux.ibm.com>
Cc: Paul Walmsley <paul.walmsley@sifive.com>
Cc: Palmer Dabbelt <palmer@dabbelt.com>
Cc: Albert Ou <aou@eecs.berkeley.edu>
Cc: Heiko Carstens <hca@linux.ibm.com>
Cc: Vasily Gorbik <gor@linux.ibm.com>
Cc: Alexander Gordeev <agordeev@linux.ibm.com>
Cc: Christian Borntraeger <borntraeger@linux.ibm.com>
Cc: Sven Schnelle <svens@linux.ibm.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: Borislav Petkov <bp@alien8.de>
Cc: Dave Hansen <dave.hansen@linux.intel.com>
Cc: "H. Peter Anvin" <hpa@zytor.com>
Signed-off-by: Steven Rostedt (Google) <rostedt@goodmis.org>
2024-06-11 11:18:24 -04:00
Linus Torvalds
5f16eb0549 Char/Misc and other driver subsystem changes for 6.10-rc1
Here is the big set of char/misc and other driver subsystem updates for
 6.10-rc1.  Nothing major here, just lots of new drivers and updates for
 apis and new hardware types.  Included in here are:
   - big IIO driver updates with more devices and drivers added
   - fpga driver updates
   - hyper-v driver updates
   - uio_pruss driver removal, no one uses it, other drivers control the
     same hardware now
   - binder minor updates
   - mhi driver updates
   - excon driver updates
   - counter driver updates
   - accessability driver updates
   - coresight driver updates
   - other hwtracing driver updates
   - nvmem driver updates
   - slimbus driver updates
   - spmi driver updates
   - other smaller misc and char driver updates
 
 All of these have been in linux-next for a while with no reported
 issues.
 
 Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
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Merge tag 'char-misc-6.10-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/gregkh/char-misc

Pull char/misc and other driver subsystem updates from Greg KH:
 "Here is the big set of char/misc and other driver subsystem updates
  for 6.10-rc1. Nothing major here, just lots of new drivers and updates
  for apis and new hardware types. Included in here are:

   - big IIO driver updates with more devices and drivers added

   - fpga driver updates

   - hyper-v driver updates

   - uio_pruss driver removal, no one uses it, other drivers control the
     same hardware now

   - binder minor updates

   - mhi driver updates

   - excon driver updates

   - counter driver updates

   - accessability driver updates

   - coresight driver updates

   - other hwtracing driver updates

   - nvmem driver updates

   - slimbus driver updates

   - spmi driver updates

   - other smaller misc and char driver updates

  All of these have been in linux-next for a while with no reported
  issues"

* tag 'char-misc-6.10-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/gregkh/char-misc: (319 commits)
  misc: ntsync: mark driver as "broken" to prevent from building
  spmi: pmic-arb: Add multi bus support
  spmi: pmic-arb: Register controller for bus instead of arbiter
  spmi: pmic-arb: Make core resources acquiring a version operation
  spmi: pmic-arb: Make the APID init a version operation
  spmi: pmic-arb: Fix some compile warnings about members not being described
  dt-bindings: spmi: Deprecate qcom,bus-id
  dt-bindings: spmi: Add X1E80100 SPMI PMIC ARB schema
  spmi: pmic-arb: Replace three IS_ERR() calls by null pointer checks in spmi_pmic_arb_probe()
  spmi: hisi-spmi-controller: Do not override device identifier
  dt-bindings: spmi: hisilicon,hisi-spmi-controller: clean up example
  dt-bindings: spmi: hisilicon,hisi-spmi-controller: fix binding references
  spmi: make spmi_bus_type const
  extcon: adc-jack: Document missing struct members
  extcon: realtek: Remove unused of_gpio.h
  extcon: usbc-cros-ec: Convert to platform remove callback returning void
  extcon: usb-gpio: Convert to platform remove callback returning void
  extcon: max77843: Convert to platform remove callback returning void
  extcon: max3355: Convert to platform remove callback returning void
  extcon: intel-mrfld: Convert to platform remove callback returning void
  ...
2024-05-22 12:26:46 -07:00
Linus Torvalds
53683e4080 tracing ring buffer updates for v6.10:
- Add ring_buffer memory mappings
 
   The tracing ring buffer was created based on being mostly used with the
   splice system call. It is broken up into page ordered sub-buffers and the
   reader swaps a new sub-buffer with an existing sub-buffer that's part
   of the write buffer. It then has total access to the swapped out
   sub-buffer and can do copyless movements of the memory into other mediums
   (file system, network, etc).
 
   The buffer is great for passing around the ring buffer contents in the
   kernel, but is not so good for when the consumer is the user space task
   itself.
 
   A new interface is added that allows user space to memory map the ring
   buffer. It will get all the write sub-buffers as well as reader sub-buffer
   (that is not written to). It can send an ioctl to change which sub-buffer
   is the new reader sub-buffer.
 
   The ring buffer is read only to user space. It only needs to call the
   ioctl when it is finished with a sub-buffer and needs a new sub-buffer
   that the writer will not write over.
 
   A self test program was also created for testing and can be used as
   an example for the interface to user space. The libtracefs (external
   to the kernel) also has code that interacts with this, although it is
   disabled until the interface is in a official release. It can be enabled
   by compiling the library with a special flag. This was used for testing
   applications that perform better with the buffer being mapped.
 
   Memory mapped buffers have limitations. The main one is that it can not be
   used with the snapshot logic. If the buffer is mapped, snapshots will be
   disabled. If any logic is set to trigger snapshots on a buffer, that
   buffer will not be allowed to be mapped.
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Merge tag 'trace-ringbuffer-v6.10' of git://git.kernel.org/pub/scm/linux/kernel/git/trace/linux-trace

Pull tracing ring buffer updates from Steven Rostedt:
 "Add ring_buffer memory mappings.

  The tracing ring buffer was created based on being mostly used with
  the splice system call. It is broken up into page ordered sub-buffers
  and the reader swaps a new sub-buffer with an existing sub-buffer
  that's part of the write buffer. It then has total access to the
  swapped out sub-buffer and can do copyless movements of the memory
  into other mediums (file system, network, etc).

  The buffer is great for passing around the ring buffer contents in the
  kernel, but is not so good for when the consumer is the user space
  task itself.

  A new interface is added that allows user space to memory map the ring
  buffer. It will get all the write sub-buffers as well as reader
  sub-buffer (that is not written to). It can send an ioctl to change
  which sub-buffer is the new reader sub-buffer.

  The ring buffer is read only to user space. It only needs to call the
  ioctl when it is finished with a sub-buffer and needs a new sub-buffer
  that the writer will not write over.

  A self test program was also created for testing and can be used as an
  example for the interface to user space. The libtracefs (external to
  the kernel) also has code that interacts with this, although it is
  disabled until the interface is in a official release. It can be
  enabled by compiling the library with a special flag. This was used
  for testing applications that perform better with the buffer being
  mapped.

  Memory mapped buffers have limitations. The main one is that it can
  not be used with the snapshot logic. If the buffer is mapped,
  snapshots will be disabled. If any logic is set to trigger snapshots
  on a buffer, that buffer will not be allowed to be mapped"

* tag 'trace-ringbuffer-v6.10' of git://git.kernel.org/pub/scm/linux/kernel/git/trace/linux-trace:
  ring-buffer: Add cast to unsigned long addr passed to virt_to_page()
  ring-buffer: Have mmapped ring buffer keep track of missed events
  ring-buffer/selftest: Add ring-buffer mapping test
  Documentation: tracing: Add ring-buffer mapping
  tracing: Allow user-space mapping of the ring-buffer
  ring-buffer: Introducing ring-buffer mapping functions
  ring-buffer: Allocate sub-buffers with __GFP_COMP
2024-05-17 18:40:37 -07:00
Linus Torvalds
70a663205d Probes updates for v6.10:
- tracing/probes: Adding new pseudo-types %pd and %pD support for dumping
   dentry name from 'struct dentry *' and file name from 'struct file *'.
 
 - uprobes: Some performance optimizations have been done.
  . Speed up the BPF uprobe event by delaying the fetching of the uprobe
    event arguments that are not used in BPF.
  . Avoid locking by speculatively checking whether uprobe event is valid.
  . Reduce lock contention by using read/write_lock instead of spinlock for
    uprobe list operation. This improved BPF uprobe benchmark result 43% on
    average.
 
 - rethook: Removes non-fatal warning messages when tracing stack from BPF
   and skip rcu_is_watching() validation in rethook if possible.
 
 - objpool: Optimizing objpool (which is used by kretprobes and fprobe as
   rethook backend storage) by inlining functions and avoid caching nr_cpu_ids
   because it is a const value.
 
 - fprobe: Add entry/exit callbacks types (code cleanup)
 - kprobes: Check ftrace was killed in kprobes if it uses ftrace.
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Merge tag 'probes-v6.10' of git://git.kernel.org/pub/scm/linux/kernel/git/trace/linux-trace

Pull probes updates from Masami Hiramatsu:

 - tracing/probes: Add new pseudo-types %pd and %pD support for dumping
   dentry name from 'struct dentry *' and file name from 'struct file *'

 - uprobes performance optimizations:
    - Speed up the BPF uprobe event by delaying the fetching of the
      uprobe event arguments that are not used in BPF
    - Avoid locking by speculatively checking whether uprobe event is
      valid
    - Reduce lock contention by using read/write_lock instead of
      spinlock for uprobe list operation. This improved BPF uprobe
      benchmark result 43% on average

 - rethook: Remove non-fatal warning messages when tracing stack from
   BPF and skip rcu_is_watching() validation in rethook if possible

 - objpool: Optimize objpool (which is used by kretprobes and fprobe as
   rethook backend storage) by inlining functions and avoid caching
   nr_cpu_ids because it is a const value

 - fprobe: Add entry/exit callbacks types (code cleanup)

 - kprobes: Check ftrace was killed in kprobes if it uses ftrace

* tag 'probes-v6.10' of git://git.kernel.org/pub/scm/linux/kernel/git/trace/linux-trace:
  kprobe/ftrace: bail out if ftrace was killed
  selftests/ftrace: Fix required features for VFS type test case
  objpool: cache nr_possible_cpus() and avoid caching nr_cpu_ids
  objpool: enable inlining objpool_push() and objpool_pop() operations
  rethook: honor CONFIG_FTRACE_VALIDATE_RCU_IS_WATCHING in rethook_try_get()
  ftrace: make extra rcu_is_watching() validation check optional
  uprobes: reduce contention on uprobes_tree access
  rethook: Remove warning messages printed for finding return address of a frame.
  fprobe: Add entry/exit callbacks types
  selftests/ftrace: add fprobe test cases for VFS type "%pd" and "%pD"
  selftests/ftrace: add kprobe test cases for VFS type "%pd" and "%pD"
  Documentation: tracing: add new type '%pd' and '%pD' for kprobe
  tracing/probes: support '%pD' type for print struct file's name
  tracing/probes: support '%pd' type for print struct dentry's name
  uprobes: add speculative lockless system-wide uprobe filter check
  uprobes: prepare uprobe args buffer lazily
  uprobes: encapsulate preparation of uprobe args buffer
2024-05-17 18:29:30 -07:00
Vincent Donnefort
a1e0dd7ce3 Documentation: tracing: Add ring-buffer mapping
It is now possible to mmap() a ring-buffer to stream its content. Add
some documentation and a code example.

Link: https://lore.kernel.org/linux-trace-kernel/20240510140435.3550353-5-vdonnefort@google.com

Signed-off-by: Vincent Donnefort <vdonnefort@google.com>
Signed-off-by: Steven Rostedt (Google) <rostedt@goodmis.org>
2024-05-13 18:09:56 -04:00
Saurav Shah
dd29dfe78b Documentation: tracing: Fix spelling mistakes
Fix spelling mistakes in the documentation.

Signed-off-by: Saurav Shah <sauravshah.31@gmail.com>
Link: https://lore.kernel.org/r/20240501233659.25441-1-sauravshah.31@gmail.com
Signed-off-by: Jonathan Corbet <corbet@lwn.net>
2024-05-07 08:00:25 -06:00
Ivan Orlov
125db341e2 docs, kprobes: Add riscv as supported architecture
Support of kprobes and kretprobes for riscv was introduced 3 years ago
by the following change:

commit c22b0bcb1d ("riscv: Add kprobes supported")

Add riscv to the list of supported architectures.

Signed-off-by: Ivan Orlov <ivan.orlov@codethink.co.uk>
Signed-off-by: Jonathan Corbet <corbet@lwn.net>
Link: https://lore.kernel.org/r/20240429155735.68781-1-ivan.orlov@codethink.co.uk
2024-05-02 10:05:25 -06:00
Jonathan Cameron
1f82d58ddb Documentation: ABI + trace: hisi_ptt: update paths to bus/event_source
To allow for assigning a suitable parent to the struct pmu device
update the documentation to describe the device via the event_source
bus where it will remain accessible.

For the ABI documention file also rename the file as it is named
after the path.

Reviewed-by: Yicong Yang <yangyicong@hisilicon.com>
Signed-off-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>
Signed-off-by: Suzuki K Poulose <suzuki.poulose@arm.com>
Link: https://lore.kernel.org/r/20240412161057.14099-30-Jonathan.Cameron@huawei.com
2024-05-02 11:36:11 +01:00
Ye Bin
5e37460f5f Documentation: tracing: add new type '%pd' and '%pD' for kprobe
Similar to printk() '%pd' is for fetch dentry's name from struct dentry's
pointer, and '%pD' is for fetch file's name from struct file's pointer.

Link: https://lore.kernel.org/all/20240322064308.284457-4-yebin10@huawei.com/

Signed-off-by: Ye Bin <yebin10@huawei.com>
Acked-by: Masami Hiramatsu (Google) <mhiramat@kernel.org>
Signed-off-by: Masami Hiramatsu (Google) <mhiramat@kernel.org>
2024-05-01 23:18:47 +09:00
Sarat Mandava
7a225ece71 trace doc: Minor grammatical correction
Use the correct relative pronoun.

Signed-off-by: Sarat Mandava <mandavasarat@gmail.com>
Signed-off-by: Jonathan Corbet <corbet@lwn.net>
Link: https://lore.kernel.org/r/20240321112757.17502-1-mandavasarat@gmail.com
2024-04-02 10:07:51 -06:00
Beau Belgrave
3727db1c09 tracing/user_events: Document multi-format flag
User programs can now ask user_events to handle the synchronization of
multiple different formats for an event with the same name via the new
USER_EVENT_REG_MULTI_FORMAT flag.

Add a section for USER_EVENT_REG_MULTI_FORMAT that explains the intended
purpose and caveats of using it. Explain how deletion works in these
cases and how to use /sys/kernel/tracing/dynamic_events for per-version
deletion.

Link: https://lore.kernel.org/linux-trace-kernel/20240222001807.1463-5-beaub@linux.microsoft.com

Signed-off-by: Beau Belgrave <beaub@linux.microsoft.com>
Signed-off-by: Steven Rostedt (Google) <rostedt@goodmis.org>
2024-03-18 10:13:16 -04:00
Masami Hiramatsu (Google)
e8c32f2476 Documentation: tracing: Add entry argument access at function exit
Add a notes about the entry argument access at function exit probes for
kprobes and fprobe trace event.

Link: https://lore.kernel.org/all/170952367549.229804.8843506960483577062.stgit@devnote2/

Signed-off-by: Masami Hiramatsu (Google) <mhiramat@kernel.org>
2024-03-07 00:27:53 +09:00
Linus Torvalds
a2ded784cd tracing updates for 6.8:
- Allow kernel trace instance creation to specify what events are created
   Inside the kernel, a subsystem may create a tracing instance that it can
   use to send events to user space. This sub-system may not care about the
   thousands of events that exist in eventfs. Allow the sub-system to specify
   what sub-systems of events it cares about, and only those events are exposed
   to this instance.
 
 - Allow the ring buffer to be broken up into bigger sub-buffers than just the
   architecture page size. A new tracefs file called "buffer_subbuf_size_kb"
   is created. The user can now specify a minimum size the sub-buffer may be
   in kilobytes. Note, that the implementation currently make the sub-buffer
   size a power of 2 pages (1, 2, 4, 8, 16, ...) but the user only writes in
   kilobyte size, and the sub-buffer will be updated to the next size that
   it will can accommodate it. If the user writes in 10, it will change the
   size to be 4 pages on x86 (16K), as that is the next available size that
   can hold 10K pages.
 
 - Update the debug output when a corrupt time is detected in the ring buffer.
   If the ring buffer detects inconsistent timestamps, there's a debug config
   options that will dump the contents of the meta data of the sub-buffer that
   is used for debugging. Add some more information to this dump that helps
   with debugging.
 
 - Add more timestamp debugging checks (only triggers when the config is enabled)
 
 - Increase the trace_seq iterator to 2 page sizes.
 
 - Allow strings written into tracefs_marker to be larger. Up to just under
   2 page sizes (based on what trace_seq can hold).
 
 - Increase the trace_maker_raw write to be as big as a sub-buffer can hold.
 
 - Remove 32 bit time stamp logic, now that the rb_time_cmpxchg() has been
   removed.
 
 - More selftests were added.
 
 - Some code clean ups as well.
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Merge tag 'trace-v6.8' of git://git.kernel.org/pub/scm/linux/kernel/git/trace/linux-trace

Pull tracing updates from Steven Rostedt:

 - Allow kernel trace instance creation to specify what events are
   created

   Inside the kernel, a subsystem may create a tracing instance that it
   can use to send events to user space. This sub-system may not care
   about the thousands of events that exist in eventfs. Allow the
   sub-system to specify what sub-systems of events it cares about, and
   only those events are exposed to this instance.

 - Allow the ring buffer to be broken up into bigger sub-buffers than
   just the architecture page size.

   A new tracefs file called "buffer_subbuf_size_kb" is created. The
   user can now specify a minimum size the sub-buffer may be in
   kilobytes. Note, that the implementation currently make the
   sub-buffer size a power of 2 pages (1, 2, 4, 8, 16, ...) but the user
   only writes in kilobyte size, and the sub-buffer will be updated to
   the next size that it will can accommodate it. If the user writes in
   10, it will change the size to be 4 pages on x86 (16K), as that is
   the next available size that can hold 10K pages.

 - Update the debug output when a corrupt time is detected in the ring
   buffer. If the ring buffer detects inconsistent timestamps, there's a
   debug config options that will dump the contents of the meta data of
   the sub-buffer that is used for debugging. Add some more information
   to this dump that helps with debugging.

 - Add more timestamp debugging checks (only triggers when the config is
   enabled)

 - Increase the trace_seq iterator to 2 page sizes.

 - Allow strings written into tracefs_marker to be larger. Up to just
   under 2 page sizes (based on what trace_seq can hold).

 - Increase the trace_maker_raw write to be as big as a sub-buffer can
   hold.

 - Remove 32 bit time stamp logic, now that the rb_time_cmpxchg() has
   been removed.

 - More selftests were added.

 - Some code clean ups as well.

* tag 'trace-v6.8' of git://git.kernel.org/pub/scm/linux/kernel/git/trace/linux-trace: (29 commits)
  ring-buffer: Remove stale comment from ring_buffer_size()
  tracing histograms: Simplify parse_actions() function
  tracing/selftests: Remove exec permissions from trace_marker.tc test
  ring-buffer: Use subbuf_order for buffer page masking
  tracing: Update subbuffer with kilobytes not page order
  ringbuffer/selftest: Add basic selftest to test changing subbuf order
  ring-buffer: Add documentation on the buffer_subbuf_order file
  ring-buffer: Just update the subbuffers when changing their allocation order
  ring-buffer: Keep the same size when updating the order
  tracing: Stop the tracing while changing the ring buffer subbuf size
  tracing: Update snapshot order along with main buffer order
  ring-buffer: Make sure the spare sub buffer used for reads has same size
  ring-buffer: Do no swap cpu buffers if order is different
  ring-buffer: Clear pages on error in ring_buffer_subbuf_order_set() failure
  ring-buffer: Read and write to ring buffers with custom sub buffer size
  ring-buffer: Set new size of the ring buffer sub page
  ring-buffer: Add interface for configuring trace sub buffer size
  ring-buffer: Page size per ring buffer
  ring-buffer: Have ring_buffer_print_page_header() be able to access ring_buffer_iter
  ring-buffer: Check if absolute timestamp goes backwards
  ...
2024-01-18 14:35:29 -08:00
Linus Torvalds
296455ade1 Char/Misc and other Driver changes for 6.8-rc1
Here is the big set of char/misc and other driver subsystem changes for
 6.8-rc1.  Lots of stuff in here, but first off, you will get a merge
 conflict in drivers/android/binder_alloc.c when merging this tree due to
 changing coming in through the -mm tree.
 
 The resolution of the merge issue can be found here:
 	https://lore.kernel.org/r/20231207134213.25631ae9@canb.auug.org.au
 or in a simpler patch form in that thread:
 	https://lore.kernel.org/r/ZXHzooF07LfQQYiE@google.com
 
 If there are issues with the merge of this file, please let me know.
 
 Other than lots of binder driver changes (as you can see by the merge
 conflicts) included in here are:
  - lots of iio driver updates and additions
  - spmi driver updates
  - eeprom driver updates
  - firmware driver updates
  - ocxl driver updates
  - mhi driver updates
  - w1 driver updates
  - nvmem driver updates
  - coresight driver updates
  - platform driver remove callback api changes
  - tags.sh script updates
  - bus_type constant marking cleanups
  - lots of other small driver updates
 
 All of these have been in linux-next for a while with no reported issues
 (other than the binder merge conflict.)
 
 Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
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Merge tag 'char-misc-6.8-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/gregkh/char-misc

Pull char/misc and other driver updates from Greg KH:
 "Here is the big set of char/misc and other driver subsystem changes
  for 6.8-rc1.

  Other than lots of binder driver changes (as you can see by the merge
  conflicts) included in here are:

   - lots of iio driver updates and additions

   - spmi driver updates

   - eeprom driver updates

   - firmware driver updates

   - ocxl driver updates

   - mhi driver updates

   - w1 driver updates

   - nvmem driver updates

   - coresight driver updates

   - platform driver remove callback api changes

   - tags.sh script updates

   - bus_type constant marking cleanups

   - lots of other small driver updates

  All of these have been in linux-next for a while with no reported
  issues"

* tag 'char-misc-6.8-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/gregkh/char-misc: (341 commits)
  android: removed duplicate linux/errno
  uio: Fix use-after-free in uio_open
  drivers: soc: xilinx: add check for platform
  firmware: xilinx: Export function to use in other module
  scripts/tags.sh: remove find_sources
  scripts/tags.sh: use -n to test archinclude
  scripts/tags.sh: add local annotation
  scripts/tags.sh: use more portable -path instead of -wholename
  scripts/tags.sh: Update comment (addition of gtags)
  firmware: zynqmp: Convert to platform remove callback returning void
  firmware: turris-mox-rwtm: Convert to platform remove callback returning void
  firmware: stratix10-svc: Convert to platform remove callback returning void
  firmware: stratix10-rsu: Convert to platform remove callback returning void
  firmware: raspberrypi: Convert to platform remove callback returning void
  firmware: qemu_fw_cfg: Convert to platform remove callback returning void
  firmware: mtk-adsp-ipc: Convert to platform remove callback returning void
  firmware: imx-dsp: Convert to platform remove callback returning void
  firmware: coreboot_table: Convert to platform remove callback returning void
  firmware: arm_scpi: Convert to platform remove callback returning void
  firmware: arm_scmi: Convert to platform remove callback returning void
  ...
2024-01-17 16:47:17 -08:00
Linus Torvalds
1b1934dbbd A handful of late-arriving documentation fixes.
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Merge tag 'docs-6.8-2' of git://git.lwn.net/linux

Pull documentation fixes from Jonathan Corbet:
 "A handful of late-arriving documentation fixes"

* tag 'docs-6.8-2' of git://git.lwn.net/linux:
  docs, kprobes: Add loongarch as supported architecture
  docs, kprobes: Update email address of Masami Hiramatsu
  docs: admin-guide: hw_random: update rng-tools website
  Documentation/core-api: fix spelling mistake in workqueue
  docs: kernel_feat.py: fix potential command injection
  Documentation: constrain alabaster package to older versions
2024-01-17 11:49:11 -08:00
Linus Torvalds
5b9b41617b Another moderately busy cycle for documentation, including:
- The minimum Sphinx requirement has been raised to 2.4.4, following a
   warning that was added in 6.2.
 
 - Some reworking of the Documentation/process front page to, hopefully,
   make it more useful.
 
 - Various kernel-doc tweaks to, for example, make it deal properly with
   __counted_by annotations.
 
 - We have also restored a warning for documentation of nonexistent
   structure members that disappeared a while back.  That had the delightful
   consequence of adding some 600 warnings to the docs build.  A sustained
   effort by Randy, Vegard, and myself has addressed almost all of those,
   bringing the documentation back into sync with the code.  The fixes are
   going through the appropriate maintainer trees.
 
 - Various improvements to the HTML rendered docs, including automatic links
   to Git revisions and a nice new pulldown to make translations easy to
   access.
 
 - Speaking of translations, more of those for Spanish and Chinese.
 
 ...plus the usual stream of documentation updates and typo fixes.
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Merge tag 'docs-6.8' of git://git.lwn.net/linux

Pull documentation update from Jonathan Corbet:
 "Another moderately busy cycle for documentation, including:

   - The minimum Sphinx requirement has been raised to 2.4.4, following
     a warning that was added in 6.2

   - Some reworking of the Documentation/process front page to,
     hopefully, make it more useful

   - Various kernel-doc tweaks to, for example, make it deal properly
     with __counted_by annotations

   - We have also restored a warning for documentation of nonexistent
     structure members that disappeared a while back. That had the
     delightful consequence of adding some 600 warnings to the docs
     build. A sustained effort by Randy, Vegard, and myself has
     addressed almost all of those, bringing the documentation back into
     sync with the code. The fixes are going through the appropriate
     maintainer trees

   - Various improvements to the HTML rendered docs, including automatic
     links to Git revisions and a nice new pulldown to make translations
     easy to access

   - Speaking of translations, more of those for Spanish and Chinese

  ... plus the usual stream of documentation updates and typo fixes"

* tag 'docs-6.8' of git://git.lwn.net/linux: (57 commits)
  MAINTAINERS: use tabs for indent of CONFIDENTIAL COMPUTING THREAT MODEL
  A reworked process/index.rst
  ring-buffer/Documentation: Add documentation on buffer_percent file
  Translated the RISC-V architecture boot documentation.
  Docs: remove mentions of fdformat from util-linux
  Docs/zh_CN: Fix the meaning of DEBUG to pr_debug()
  Documentation: move driver-api/dcdbas to userspace-api/
  Documentation: move driver-api/isapnp to userspace-api/
  Documentation/core-api : fix typo in workqueue
  Documentation/trace: Fixed typos in the ftrace FLAGS section
  kernel-doc: handle a void function without producing a warning
  scripts/get_abi.pl: ignore some temp files
  docs: kernel_abi.py: fix command injection
  scripts/get_abi: fix source path leak
  CREDITS, MAINTAINERS, docs/process/howto: Update man-pages' maintainer
  docs: translations: add translations links when they exist
  kernel-doc: Align quick help and the code
  MAINTAINERS: add reviewer for Spanish translations
  docs: ignore __counted_by attribute in structure definitions
  scripts: kernel-doc: Clarify missing struct member description
  ..
2024-01-11 19:46:52 -08:00
Tiezhu Yang
ead8467f96 docs, kprobes: Add loongarch as supported architecture
After the following three changes at the beginning of the year:

  commit 6d4cc40fb5 ("LoongArch: Add kprobes support")
  commit 3f55368600 ("LoongArch: Add kretprobes support")
  commit 09e679c28a ("LoongArch: Add kprobes on ftrace support")

it is appropriate to add loongarch as supported architecture in
kprobes documentation.

Signed-off-by: Tiezhu Yang <yangtiezhu@loongson.cn>
Acked-by: "Masami Hiramatsu (Google)" <mhiramat@kernel.org>
Signed-off-by: Jonathan Corbet <corbet@lwn.net>
Link: https://lore.kernel.org/r/20231219062330.22813-3-yangtiezhu@loongson.cn
2024-01-11 09:36:37 -07:00
Tiezhu Yang
b65a6b44f0 docs, kprobes: Update email address of Masami Hiramatsu
According to the latest authorship and Signed-off-by:

  Masami Hiramatsu (Google) <mhiramat@kernel.org>

Masami Hiramatsu is working at Google, so the current email @redhat.com
is out of date, it is better to use the email @kernel.org.

Signed-off-by: Tiezhu Yang <yangtiezhu@loongson.cn>
Acked-by: "Masami Hiramatsu (Google)" <mhiramat@kernel.org>
Signed-off-by: Jonathan Corbet <corbet@lwn.net>
Link: https://lore.kernel.org/r/20231219062330.22813-2-yangtiezhu@loongson.cn
2024-01-11 09:36:37 -07:00
Steven Rostedt (Google)
4b2df884b8 ring-buffer/Documentation: Add documentation on buffer_percent file
When the buffer_percent file was added to the kernel, the documentation
should have been updated to document what that file does.

Acked-by: "Masami Hiramatsu (Google)" <mhiramat@kernel.org>
Fixes: 03329f9939 ("tracing: Add tracefs file buffer_percentage")
Signed-off-by: "Steven Rostedt (Google)" <rostedt@goodmis.org>
Acked-by: Randy Dunlap <rdunlap@infradead.org>
Signed-off-by: Jonathan Corbet <corbet@lwn.net>
Link: https://lore.kernel.org/r/20231229122402.537eb252@gandalf.local.home
2024-01-03 14:41:52 -07:00
Matthew Cassell
d3f79db932 Documentation/trace: Fixed typos in the ftrace FLAGS section
Fixed typos in the FTRACE_OPS_FL_RECURSION flag description.

Signed-off-by: Matthew Cassell <mcassell411@gmail.com>
Reviewed-by: Randy Dunlap <rdunlap@infradead.org>
Signed-off-by: Jonathan Corbet <corbet@lwn.net>
Link: https://lore.kernel.org/r/20231223185845.2326-1-mcassell411@gmail.com
2024-01-03 14:15:53 -07:00
Steven Rostedt (Google)
2f84b39f48 tracing: Update subbuffer with kilobytes not page order
Using page order for deciding what the size of the ring buffer sub buffers
are is exposing a bit too much of the implementation. Although the sub
buffers are only allocated in orders of pages, allow the user to specify
the minimum size of each sub-buffer via kilobytes like they can with the
buffer size itself.

If the user specifies 3 via:

  echo 3 > buffer_subbuf_size_kb

Then the sub-buffer size will round up to 4kb (on a 4kb page size system).

If they specify:

  echo 6 > buffer_subbuf_size_kb

The sub-buffer size will become 8kb.

and so on.

Link: https://lore.kernel.org/linux-trace-kernel/20231219185631.809766769@goodmis.org

Cc: Masami Hiramatsu <mhiramat@kernel.org>
Cc: Mark Rutland <mark.rutland@arm.com>
Cc: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: Tzvetomir Stoyanov <tz.stoyanov@gmail.com>
Cc: Vincent Donnefort <vdonnefort@google.com>
Cc: Kent Overstreet <kent.overstreet@gmail.com>
Signed-off-by: Steven Rostedt (Google) <rostedt@goodmis.org>
2023-12-21 11:04:15 -05:00
Steven Rostedt (Google)
7c3f480265 ring-buffer: Add documentation on the buffer_subbuf_order file
Add to the documentation how to use the buffer_subbuf_order file to change
the size and how it affects what events can be added to the ring buffer.

Link: https://lore.kernel.org/linux-trace-kernel/20231219185631.230636734@goodmis.org

Cc: Masami Hiramatsu <mhiramat@kernel.org>
Cc: Mark Rutland <mark.rutland@arm.com>
Cc: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: Tzvetomir Stoyanov <tz.stoyanov@gmail.com>
Cc: Vincent Donnefort <vdonnefort@google.com>
Cc: Kent Overstreet <kent.overstreet@gmail.com>
Signed-off-by: Steven Rostedt (Google) <rostedt@goodmis.org>
2023-12-21 11:03:13 -05:00
Yuanhsi Chung
7c49ca6b02 Documentation: Fix filename typo in ftrace doc
The filename for setting the cpumask should be `tracing_cpumask`,
instead of `tracing_cpu_mask`.

Signed-off-by: Yuanhsi Chung <freshliver.cys@gmail.com>
Signed-off-by: Jonathan Corbet <corbet@lwn.net>
Message-ID: <20231104103329.215139-1-freshliver.cys@gmail.com>
2023-11-17 09:07:02 -07:00
Anshuman Khandual
e5d207b24c Documentation: coresight: Add cc_threshold tunable
This updates config option to include 'cc_threshold' tunable value.

Cc: Suzuki K Poulose <suzuki.poulose@arm.com>
Cc: Mike Leach <mike.leach@linaro.org>
Cc: James Clark <james.clark@arm.com>
Cc: Jonathan Corbet <corbet@lwn.net>
Cc: coresight@lists.linaro.org
Cc: linux-arm-kernel@lists.infradead.org
Cc: linux-doc@vger.kernel.org
Cc: linux-kernel@vger.kernel.org
Reviewed by: Mike Leach <mike.leach@linaro.org>
Signed-off-by: Anshuman Khandual <anshuman.khandual@arm.com>
Signed-off-by: Suzuki K Poulose <suzuki.poulose@arm.com>
Link: https://lore.kernel.org/r/20230921033631.1298723-4-anshuman.khandual@arm.com
2023-11-16 11:35:09 +00:00
Vegard Nossum
e49c0b1401 Documentation: coresight: fix make refcheckdocs warning
This reference uses a glob pattern to match multiple files, but the
asterisk was escaped as \* in order to not be interpreted by sphinx
as reStructuredText markup.

refcheckdocs/documentation-file-ref-check doesn't know about rST syntax
and tries to interpret the \* literally (instead of as a glob).

We can work around the warning by putting the Documentation reference
inside double backticks (``..``), which allows us to not escape the
asterisk.

Fixes: c06475910b ("Documentation: coresight: Escape coresight bindings file wildcard")
Cc: Mathieu Poirier <mathieu.poirier@linaro.org>
Cc: Suzuki K Poulose <suzuki.poulose@arm.com>
Cc: Mike Leach <mike.leach@linaro.org>
Cc: Leo Yan <leo.yan@linaro.org>
Cc: Jonathan Corbet <corbet@lwn.net>
Cc: Rob Herring <robh@kernel.org>
Cc: coresight@lists.linaro.org
Cc: linux-arm-kernel@lists.infradead.org
Cc: linux-next@vger.kernel.org
Cc: linux-kernel@vger.kernel.org
Cc: Stephen Rothwell <sfr@canb.auug.org.au>
Cc: Bagas Sanjaya <bagasdotme@gmail.com>
Signed-off-by: Vegard Nossum <vegard.nossum@oracle.com>
Reviewed-by: Bagas Sanjaya <bagasdotme@gmail.com>
Signed-off-by: Suzuki K Poulose <suzuki.poulose@arm.com>
Link: https://lore.kernel.org/r/20231022185806.919434-1-vegard.nossum@oracle.com
2023-11-16 09:52:39 +00:00
Masami Hiramatsu (Google)
b2a866975f Documentation: tracing: Add a note about argument and retval access
Add a note about the argument and return value accecss will be best
effort. Depending on the type, it will be passed via stack or a
pair of the registers, but $argN and $retval only support the
single register access.

Link: https://lore.kernel.org/all/169556269377.146934.14829235476649685954.stgit@devnote2/

Suggested-by: Alexei Starovoitov <alexei.starovoitov@gmail.com>
Signed-off-by: Masami Hiramatsu (Google) <mhiramat@kernel.org>
2023-11-10 19:59:03 +09:00
Linus Torvalds
31e5f934ff Tracing updates for v6.7:
- Remove eventfs_file descriptor
 
   This is the biggest change, and the second part of making eventfs
   create its files dynamically.
 
   In 6.6 the first part was added, and that maintained a one to one
   mapping between eventfs meta descriptors and the directories and
   file inodes and dentries that were dynamically created. The
   directories were represented by a eventfs_inode and the files
   were represented by a eventfs_file.
 
   In v6.7 the eventfs_file is removed. As all events have the same
   directory make up (sched_switch has an "enable", "id", "format",
   etc files), the handing of what files are underneath each leaf
   eventfs directory is moved back to the tracing subsystem via a
   callback. When a event is added to the eventfs, it registers
   an array of evenfs_entry's. These hold the names of the files and
   the callbacks to call when the file is referenced. The callback gets
   the name so that the same callback may be used by multiple files.
   The callback then supplies the filesystem_operations structure needed
   to create this file.
 
   This has brought the memory footprint of creating multiple eventfs
   instances down by 2 megs each!
 
 - User events now has persistent events that are not associated
   to a single processes. These are privileged events that hang around
   even if no process is attached to them.
 
 - Clean up of seq_buf.
   There's talk about using seq_buf more to replace strscpy() and friends.
   But this also requires some minor modifications of seq_buf to be
   able to do this.
 
 - Expand instance ring buffers individually
   Currently if boot up creates an instance, and a trace event is
   enabled on that instance, the ring buffer for that instance and the
   top level ring buffer are expanded (1.4 MB per CPU). This wastes
   memory as this happens when nothing is using the top level instance.
 
 - Other minor clean ups and fixes.
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Merge tag 'trace-v6.7' of git://git.kernel.org/pub/scm/linux/kernel/git/trace/linux-trace

Pull tracing updates from Steven Rostedt:

 - Remove eventfs_file descriptor

   This is the biggest change, and the second part of making eventfs
   create its files dynamically.

   In 6.6 the first part was added, and that maintained a one to one
   mapping between eventfs meta descriptors and the directories and file
   inodes and dentries that were dynamically created. The directories
   were represented by a eventfs_inode and the files were represented by
   a eventfs_file.

   In v6.7 the eventfs_file is removed. As all events have the same
   directory make up (sched_switch has an "enable", "id", "format", etc
   files), the handing of what files are underneath each leaf eventfs
   directory is moved back to the tracing subsystem via a callback.

   When an event is added to the eventfs, it registers an array of
   evenfs_entry's. These hold the names of the files and the callbacks
   to call when the file is referenced. The callback gets the name so
   that the same callback may be used by multiple files. The callback
   then supplies the filesystem_operations structure needed to create
   this file.

   This has brought the memory footprint of creating multiple eventfs
   instances down by 2 megs each!

 - User events now has persistent events that are not associated to a
   single processes. These are privileged events that hang around even
   if no process is attached to them

 - Clean up of seq_buf

   There's talk about using seq_buf more to replace strscpy() and
   friends. But this also requires some minor modifications of seq_buf
   to be able to do this

 - Expand instance ring buffers individually

   Currently if boot up creates an instance, and a trace event is
   enabled on that instance, the ring buffer for that instance and the
   top level ring buffer are expanded (1.4 MB per CPU). This wastes
   memory as this happens when nothing is using the top level instance

 - Other minor clean ups and fixes

* tag 'trace-v6.7' of git://git.kernel.org/pub/scm/linux/kernel/git/trace/linux-trace: (34 commits)
  seq_buf: Export seq_buf_puts()
  seq_buf: Export seq_buf_putc()
  eventfs: Use simple_recursive_removal() to clean up dentries
  eventfs: Remove special processing of dput() of events directory
  eventfs: Delete eventfs_inode when the last dentry is freed
  eventfs: Hold eventfs_mutex when calling callback functions
  eventfs: Save ownership and mode
  eventfs: Test for ei->is_freed when accessing ei->dentry
  eventfs: Have a free_ei() that just frees the eventfs_inode
  eventfs: Remove "is_freed" union with rcu head
  eventfs: Fix kerneldoc of eventfs_remove_rec()
  tracing: Have the user copy of synthetic event address use correct context
  eventfs: Remove extra dget() in eventfs_create_events_dir()
  tracing: Have trace_event_file have ref counters
  seq_buf: Introduce DECLARE_SEQ_BUF and seq_buf_str()
  eventfs: Fix typo in eventfs_inode union comment
  eventfs: Fix WARN_ON() in create_file_dentry()
  powerpc: Remove initialisation of readpos
  tracing/histograms: Simplify last_cmd_set()
  seq_buf: fix a misleading comment
  ...
2023-11-03 07:41:18 -10:00
Linus Torvalds
ecae0bd517 Many singleton patches against the MM code. The patch series which are
included in this merge do the following:
 
 - Kemeng Shi has contributed some compation maintenance work in the
   series "Fixes and cleanups to compaction".
 
 - Joel Fernandes has a patchset ("Optimize mremap during mutual
   alignment within PMD") which fixes an obscure issue with mremap()'s
   pagetable handling during a subsequent exec(), based upon an
   implementation which Linus suggested.
 
 - More DAMON/DAMOS maintenance and feature work from SeongJae Park i the
   following patch series:
 
 	mm/damon: misc fixups for documents, comments and its tracepoint
 	mm/damon: add a tracepoint for damos apply target regions
 	mm/damon: provide pseudo-moving sum based access rate
 	mm/damon: implement DAMOS apply intervals
 	mm/damon/core-test: Fix memory leaks in core-test
 	mm/damon/sysfs-schemes: Do DAMOS tried regions update for only one apply interval
 
 - In the series "Do not try to access unaccepted memory" Adrian Hunter
   provides some fixups for the recently-added "unaccepted memory' feature.
   To increase the feature's checking coverage.  "Plug a few gaps where
   RAM is exposed without checking if it is unaccepted memory".
 
 - In the series "cleanups for lockless slab shrink" Qi Zheng has done
   some maintenance work which is preparation for the lockless slab
   shrinking code.
 
 - Qi Zheng has redone the earlier (and reverted) attempt to make slab
   shrinking lockless in the series "use refcount+RCU method to implement
   lockless slab shrink".
 
 - David Hildenbrand contributes some maintenance work for the rmap code
   in the series "Anon rmap cleanups".
 
 - Kefeng Wang does more folio conversions and some maintenance work in
   the migration code.  Series "mm: migrate: more folio conversion and
   unification".
 
 - Matthew Wilcox has fixed an issue in the buffer_head code which was
   causing long stalls under some heavy memory/IO loads.  Some cleanups
   were added on the way.  Series "Add and use bdev_getblk()".
 
 - In the series "Use nth_page() in place of direct struct page
   manipulation" Zi Yan has fixed a potential issue with the direct
   manipulation of hugetlb page frames.
 
 - In the series "mm: hugetlb: Skip initialization of gigantic tail
   struct pages if freed by HVO" has improved our handling of gigantic
   pages in the hugetlb vmmemmep optimizaton code.  This provides
   significant boot time improvements when significant amounts of gigantic
   pages are in use.
 
 - Matthew Wilcox has sent the series "Small hugetlb cleanups" - code
   rationalization and folio conversions in the hugetlb code.
 
 - Yin Fengwei has improved mlock()'s handling of large folios in the
   series "support large folio for mlock"
 
 - In the series "Expose swapcache stat for memcg v1" Liu Shixin has
   added statistics for memcg v1 users which are available (and useful)
   under memcg v2.
 
 - Florent Revest has enhanced the MDWE (Memory-Deny-Write-Executable)
   prctl so that userspace may direct the kernel to not automatically
   propagate the denial to child processes.  The series is named "MDWE
   without inheritance".
 
 - Kefeng Wang has provided the series "mm: convert numa balancing
   functions to use a folio" which does what it says.
 
 - In the series "mm/ksm: add fork-exec support for prctl" Stefan Roesch
   makes is possible for a process to propagate KSM treatment across
   exec().
 
 - Huang Ying has enhanced memory tiering's calculation of memory
   distances.  This is used to permit the dax/kmem driver to use "high
   bandwidth memory" in addition to Optane Data Center Persistent Memory
   Modules (DCPMM).  The series is named "memory tiering: calculate
   abstract distance based on ACPI HMAT"
 
 - In the series "Smart scanning mode for KSM" Stefan Roesch has
   optimized KSM by teaching it to retain and use some historical
   information from previous scans.
 
 - Yosry Ahmed has fixed some inconsistencies in memcg statistics in the
   series "mm: memcg: fix tracking of pending stats updates values".
 
 - In the series "Implement IOCTL to get and optionally clear info about
   PTEs" Peter Xu has added an ioctl to /proc/<pid>/pagemap which permits
   us to atomically read-then-clear page softdirty state.  This is mainly
   used by CRIU.
 
 - Hugh Dickins contributed the series "shmem,tmpfs: general maintenance"
   - a bunch of relatively minor maintenance tweaks to this code.
 
 - Matthew Wilcox has increased the use of the VMA lock over file-backed
   page faults in the series "Handle more faults under the VMA lock".  Some
   rationalizations of the fault path became possible as a result.
 
 - In the series "mm/rmap: convert page_move_anon_rmap() to
   folio_move_anon_rmap()" David Hildenbrand has implemented some cleanups
   and folio conversions.
 
 - In the series "various improvements to the GUP interface" Lorenzo
   Stoakes has simplified and improved the GUP interface with an eye to
   providing groundwork for future improvements.
 
 - Andrey Konovalov has sent along the series "kasan: assorted fixes and
   improvements" which does those things.
 
 - Some page allocator maintenance work from Kemeng Shi in the series
   "Two minor cleanups to break_down_buddy_pages".
 
 - In thes series "New selftest for mm" Breno Leitao has developed
   another MM self test which tickles a race we had between madvise() and
   page faults.
 
 - In the series "Add folio_end_read" Matthew Wilcox provides cleanups
   and an optimization to the core pagecache code.
 
 - Nhat Pham has added memcg accounting for hugetlb memory in the series
   "hugetlb memcg accounting".
 
 - Cleanups and rationalizations to the pagemap code from Lorenzo
   Stoakes, in the series "Abstract vma_merge() and split_vma()".
 
 - Audra Mitchell has fixed issues in the procfs page_owner code's new
   timestamping feature which was causing some misbehaviours.  In the
   series "Fix page_owner's use of free timestamps".
 
 - Lorenzo Stoakes has fixed the handling of new mappings of sealed files
   in the series "permit write-sealed memfd read-only shared mappings".
 
 - Mike Kravetz has optimized the hugetlb vmemmap optimization in the
   series "Batch hugetlb vmemmap modification operations".
 
 - Some buffer_head folio conversions and cleanups from Matthew Wilcox in
   the series "Finish the create_empty_buffers() transition".
 
 - As a page allocator performance optimization Huang Ying has added
   automatic tuning to the allocator's per-cpu-pages feature, in the series
   "mm: PCP high auto-tuning".
 
 - Roman Gushchin has contributed the patchset "mm: improve performance
   of accounted kernel memory allocations" which improves their performance
   by ~30% as measured by a micro-benchmark.
 
 - folio conversions from Kefeng Wang in the series "mm: convert page
   cpupid functions to folios".
 
 - Some kmemleak fixups in Liu Shixin's series "Some bugfix about
   kmemleak".
 
 - Qi Zheng has improved our handling of memoryless nodes by keeping them
   off the allocation fallback list.  This is done in the series "handle
   memoryless nodes more appropriately".
 
 - khugepaged conversions from Vishal Moola in the series "Some
   khugepaged folio conversions".
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Merge tag 'mm-stable-2023-11-01-14-33' of git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm

Pull MM updates from Andrew Morton:
 "Many singleton patches against the MM code. The patch series which are
  included in this merge do the following:

   - Kemeng Shi has contributed some compation maintenance work in the
     series 'Fixes and cleanups to compaction'

   - Joel Fernandes has a patchset ('Optimize mremap during mutual
     alignment within PMD') which fixes an obscure issue with mremap()'s
     pagetable handling during a subsequent exec(), based upon an
     implementation which Linus suggested

   - More DAMON/DAMOS maintenance and feature work from SeongJae Park i
     the following patch series:

	mm/damon: misc fixups for documents, comments and its tracepoint
	mm/damon: add a tracepoint for damos apply target regions
	mm/damon: provide pseudo-moving sum based access rate
	mm/damon: implement DAMOS apply intervals
	mm/damon/core-test: Fix memory leaks in core-test
	mm/damon/sysfs-schemes: Do DAMOS tried regions update for only one apply interval

   - In the series 'Do not try to access unaccepted memory' Adrian
     Hunter provides some fixups for the recently-added 'unaccepted
     memory' feature. To increase the feature's checking coverage. 'Plug
     a few gaps where RAM is exposed without checking if it is
     unaccepted memory'

   - In the series 'cleanups for lockless slab shrink' Qi Zheng has done
     some maintenance work which is preparation for the lockless slab
     shrinking code

   - Qi Zheng has redone the earlier (and reverted) attempt to make slab
     shrinking lockless in the series 'use refcount+RCU method to
     implement lockless slab shrink'

   - David Hildenbrand contributes some maintenance work for the rmap
     code in the series 'Anon rmap cleanups'

   - Kefeng Wang does more folio conversions and some maintenance work
     in the migration code. Series 'mm: migrate: more folio conversion
     and unification'

   - Matthew Wilcox has fixed an issue in the buffer_head code which was
     causing long stalls under some heavy memory/IO loads. Some cleanups
     were added on the way. Series 'Add and use bdev_getblk()'

   - In the series 'Use nth_page() in place of direct struct page
     manipulation' Zi Yan has fixed a potential issue with the direct
     manipulation of hugetlb page frames

   - In the series 'mm: hugetlb: Skip initialization of gigantic tail
     struct pages if freed by HVO' has improved our handling of gigantic
     pages in the hugetlb vmmemmep optimizaton code. This provides
     significant boot time improvements when significant amounts of
     gigantic pages are in use

   - Matthew Wilcox has sent the series 'Small hugetlb cleanups' - code
     rationalization and folio conversions in the hugetlb code

   - Yin Fengwei has improved mlock()'s handling of large folios in the
     series 'support large folio for mlock'

   - In the series 'Expose swapcache stat for memcg v1' Liu Shixin has
     added statistics for memcg v1 users which are available (and
     useful) under memcg v2

   - Florent Revest has enhanced the MDWE (Memory-Deny-Write-Executable)
     prctl so that userspace may direct the kernel to not automatically
     propagate the denial to child processes. The series is named 'MDWE
     without inheritance'

   - Kefeng Wang has provided the series 'mm: convert numa balancing
     functions to use a folio' which does what it says

   - In the series 'mm/ksm: add fork-exec support for prctl' Stefan
     Roesch makes is possible for a process to propagate KSM treatment
     across exec()

   - Huang Ying has enhanced memory tiering's calculation of memory
     distances. This is used to permit the dax/kmem driver to use 'high
     bandwidth memory' in addition to Optane Data Center Persistent
     Memory Modules (DCPMM). The series is named 'memory tiering:
     calculate abstract distance based on ACPI HMAT'

   - In the series 'Smart scanning mode for KSM' Stefan Roesch has
     optimized KSM by teaching it to retain and use some historical
     information from previous scans

   - Yosry Ahmed has fixed some inconsistencies in memcg statistics in
     the series 'mm: memcg: fix tracking of pending stats updates
     values'

   - In the series 'Implement IOCTL to get and optionally clear info
     about PTEs' Peter Xu has added an ioctl to /proc/<pid>/pagemap
     which permits us to atomically read-then-clear page softdirty
     state. This is mainly used by CRIU

   - Hugh Dickins contributed the series 'shmem,tmpfs: general
     maintenance', a bunch of relatively minor maintenance tweaks to
     this code

   - Matthew Wilcox has increased the use of the VMA lock over
     file-backed page faults in the series 'Handle more faults under the
     VMA lock'. Some rationalizations of the fault path became possible
     as a result

   - In the series 'mm/rmap: convert page_move_anon_rmap() to
     folio_move_anon_rmap()' David Hildenbrand has implemented some
     cleanups and folio conversions

   - In the series 'various improvements to the GUP interface' Lorenzo
     Stoakes has simplified and improved the GUP interface with an eye
     to providing groundwork for future improvements

   - Andrey Konovalov has sent along the series 'kasan: assorted fixes
     and improvements' which does those things

   - Some page allocator maintenance work from Kemeng Shi in the series
     'Two minor cleanups to break_down_buddy_pages'

   - In thes series 'New selftest for mm' Breno Leitao has developed
     another MM self test which tickles a race we had between madvise()
     and page faults

   - In the series 'Add folio_end_read' Matthew Wilcox provides cleanups
     and an optimization to the core pagecache code

   - Nhat Pham has added memcg accounting for hugetlb memory in the
     series 'hugetlb memcg accounting'

   - Cleanups and rationalizations to the pagemap code from Lorenzo
     Stoakes, in the series 'Abstract vma_merge() and split_vma()'

   - Audra Mitchell has fixed issues in the procfs page_owner code's new
     timestamping feature which was causing some misbehaviours. In the
     series 'Fix page_owner's use of free timestamps'

   - Lorenzo Stoakes has fixed the handling of new mappings of sealed
     files in the series 'permit write-sealed memfd read-only shared
     mappings'

   - Mike Kravetz has optimized the hugetlb vmemmap optimization in the
     series 'Batch hugetlb vmemmap modification operations'

   - Some buffer_head folio conversions and cleanups from Matthew Wilcox
     in the series 'Finish the create_empty_buffers() transition'

   - As a page allocator performance optimization Huang Ying has added
     automatic tuning to the allocator's per-cpu-pages feature, in the
     series 'mm: PCP high auto-tuning'

   - Roman Gushchin has contributed the patchset 'mm: improve
     performance of accounted kernel memory allocations' which improves
     their performance by ~30% as measured by a micro-benchmark

   - folio conversions from Kefeng Wang in the series 'mm: convert page
     cpupid functions to folios'

   - Some kmemleak fixups in Liu Shixin's series 'Some bugfix about
     kmemleak'

   - Qi Zheng has improved our handling of memoryless nodes by keeping
     them off the allocation fallback list. This is done in the series
     'handle memoryless nodes more appropriately'

   - khugepaged conversions from Vishal Moola in the series 'Some
     khugepaged folio conversions'"

[ bcachefs conflicts with the dynamically allocated shrinkers have been
  resolved as per Stephen Rothwell in

     https://lore.kernel.org/all/20230913093553.4290421e@canb.auug.org.au/

  with help from Qi Zheng.

  The clone3 test filtering conflict was half-arsed by yours truly ]

* tag 'mm-stable-2023-11-01-14-33' of git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm: (406 commits)
  mm/damon/sysfs: update monitoring target regions for online input commit
  mm/damon/sysfs: remove requested targets when online-commit inputs
  selftests: add a sanity check for zswap
  Documentation: maple_tree: fix word spelling error
  mm/vmalloc: fix the unchecked dereference warning in vread_iter()
  zswap: export compression failure stats
  Documentation: ubsan: drop "the" from article title
  mempolicy: migration attempt to match interleave nodes
  mempolicy: mmap_lock is not needed while migrating folios
  mempolicy: alloc_pages_mpol() for NUMA policy without vma
  mm: add page_rmappable_folio() wrapper
  mempolicy: remove confusing MPOL_MF_LAZY dead code
  mempolicy: mpol_shared_policy_init() without pseudo-vma
  mempolicy trivia: use pgoff_t in shared mempolicy tree
  mempolicy trivia: slightly more consistent naming
  mempolicy trivia: delete those ancient pr_debug()s
  mempolicy: fix migrate_pages(2) syscall return nr_failed
  kernfs: drop shared NUMA mempolicy hooks
  hugetlbfs: drop shared NUMA mempolicy pretence
  mm/damon/sysfs-test: add a unit test for damon_sysfs_set_targets()
  ...
2023-11-02 19:38:47 -10:00
Linus Torvalds
1e0c505e13 asm-generic updates for v6.7
The ia64 architecture gets its well-earned retirement as planned,
 now that there is one last (mostly) working release that will
 be maintained as an LTS kernel.
 
 The architecture specific system call tables are updated for
 the added map_shadow_stack() syscall and to remove references
 to the long-gone sys_lookup_dcookie() syscall.
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Merge tag 'asm-generic-6.7' of git://git.kernel.org/pub/scm/linux/kernel/git/arnd/asm-generic

Pull ia64 removal and asm-generic updates from Arnd Bergmann:

 - The ia64 architecture gets its well-earned retirement as planned,
   now that there is one last (mostly) working release that will be
   maintained as an LTS kernel.

 - The architecture specific system call tables are updated for the
   added map_shadow_stack() syscall and to remove references to the
   long-gone sys_lookup_dcookie() syscall.

* tag 'asm-generic-6.7' of git://git.kernel.org/pub/scm/linux/kernel/git/arnd/asm-generic:
  hexagon: Remove unusable symbols from the ptrace.h uapi
  asm-generic: Fix spelling of architecture
  arch: Reserve map_shadow_stack() syscall number for all architectures
  syscalls: Cleanup references to sys_lookup_dcookie()
  Documentation: Drop or replace remaining mentions of IA64
  lib/raid6: Drop IA64 support
  Documentation: Drop IA64 from feature descriptions
  kernel: Drop IA64 support from sig_fault handlers
  arch: Remove Itanium (IA-64) architecture
2023-11-01 15:28:33 -10:00