linux/kernel/trace
Steven Rostedt 428add559b tracing: Have tracer option be instance specific
Tracers can add specify options to modify them. This logic was added
before instances were created and the tracer flags were global variables.
After instances were created where a tracer may exist in more than one
instance, the flags were not updated from being global into instance
specific. This causes confusion with these options. For example, the
function tracer has an option to enable function arguments:

  # cd /sys/kernel/tracing
  # mkdir instances/foo
  # echo function > instances/foo/current_tracer
  # echo 1 > options/func-args
  # echo function > current_tracer
  # cat trace
[..]
  <idle>-0       [005] d..3.  1050.656187: rcu_needs_cpu() <-tick_nohz_next_event
  <idle>-0       [005] d..3.  1050.656188: get_next_timer_interrupt(basej=0x10002dbad, basem=0xf45fd7d300) <-tick_nohz_next_event
  <idle>-0       [005] d..3.  1050.656189: _raw_spin_lock(lock=0xffff8944bdf5de80) <-__get_next_timer_interrupt
  <idle>-0       [005] d..4.  1050.656190: do_raw_spin_lock(lock=0xffff8944bdf5de80) <-__get_next_timer_interrupt
  <idle>-0       [005] d..4.  1050.656191: _raw_spin_lock_nested(lock=0xffff8944bdf5f140, subclass=1) <-__get_next_timer_interrupt
 # cat instances/foo/options/func-args
 1
 # cat instances/foo/trace
[..]
  kworker/4:1-88      [004] ...1.   298.127735: next_zone <-refresh_cpu_vm_stats
  kworker/4:1-88      [004] ...1.   298.127736: first_online_pgdat <-refresh_cpu_vm_stats
  kworker/4:1-88      [004] ...1.   298.127738: next_online_pgdat <-refresh_cpu_vm_stats
  kworker/4:1-88      [004] ...1.   298.127739: fold_diff <-refresh_cpu_vm_stats
  kworker/4:1-88      [004] ...1.   298.127741: round_jiffies_relative <-vmstat_update
[..]

The above shows that setting "func-args" in the top level instance also
set it in the instance "foo", but since the interface of the trace flags
are per instance, the update didn't take affect in the "foo" instance.

Update the infrastructure to allow tracers to add a "default_flags" field
in the tracer structure that can be set instead of "flags" which will make
the flags per instance. If a tracer needs to keep the flags global (like
blktrace), keeping the "flags" field set will keep the old behavior.

This does not update function or the function graph tracers. That will be
handled later.

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://patch.msgid.link/20251111232429.305317942@kernel.org
Fixes: f20a580627 ("ftrace: Allow instances to use function tracing")
Signed-off-by: Steven Rostedt (Google) <rostedt@goodmis.org>
2025-11-12 09:59:54 -05:00
..
rv rv: Make rtapp/pagefault monitor depends on CONFIG_MMU 2025-10-20 12:47:40 +02:00
blktrace.c tracing: Allow tracer to add more than 32 options 2025-11-04 21:44:00 +09:00
bpf_trace.c file->f_path constification 2025-10-03 16:32:36 -07:00
bpf_trace.h tracing/treewide: Remove second parameter of __assign_str() 2024-05-22 20:14:47 -04:00
error_report-traces.c
fgraph.c tracing: fgraph: Protect return handler from recursion loop 2025-09-27 09:04:05 -04:00
fprobe.c tracing: fprobe: Fix to remove recorded module addresses from filter 2025-09-24 23:18:26 +09:00
ftrace_internal.h function_graph: Make fgraph_update_pid_func() a stub for !DYNAMIC_FTRACE 2024-06-10 18:08:23 -04:00
ftrace.c tracing: Add an option to show symbols in _text+offset for function profiler 2025-11-04 21:44:18 +09:00
Kconfig tracing: Add a config and syscall_user_buf_size file to limit amount written 2025-10-28 20:10:59 -04:00
kprobe_event_gen_test.c tracing: Fix wrong return in kprobe_event_gen_test.c 2023-03-19 12:20:48 -04:00
Makefile tracing: Have eprobes have their own config option 2025-07-30 10:38:43 -04:00
pid_list.c tracing: Cleanup upper_empty() in pid_list 2025-05-14 11:19:32 -04:00
pid_list.h
power-traces.c PM: cpufreq: powernv/tracing: Move powernv_throttle trace event 2025-07-21 16:40:56 -04:00
preemptirq_delay_test.c kernel: trace: preemptirq_delay_test: use offstack cpu mask 2025-07-08 18:17:38 -04:00
rethook.c rethook: honor CONFIG_FTRACE_VALIDATE_RCU_IS_WATCHING in rethook_try_get() 2024-05-01 23:18:48 +09:00
ring_buffer_benchmark.c ring-buffer: Use str_low_high() helper in ring_buffer_producer() 2024-10-19 11:12:25 -04:00
ring_buffer.c ring buffer: Propagate __rb_map_vma return value to caller 2025-10-08 21:48:58 -04:00
rpm-traces.c
synth_event_gen_test.c tracing / synthetic: Disable events after testing in synth_event_gen_test_init() 2023-12-21 10:04:45 -05:00
trace_benchmark.c tracing: Improve benchmark test performance by using do_div() 2024-05-13 20:00:57 -04:00
trace_benchmark.h tracing: Add numeric delta time to the trace event benchmark 2022-09-26 13:01:09 -04:00
trace_boot.c tracing: Allow creating instances with specified system events 2023-12-18 23:14:16 -05:00
trace_branch.c tracing: branch: Use trace_tracing_is_on_cpu() instead of "disabled" field 2025-05-09 15:19:10 -04:00
trace_btf.c tracing/probes: Fix to search structure fields correctly 2024-02-17 21:25:42 +09:00
trace_btf.h tracing/probes: Add a function to search a member of a struct/union 2023-08-23 09:40:16 +09:00
trace_clock.c tracing: Use atomic64_inc_return() in trace_clock_counter() 2024-10-09 19:59:49 -04:00
trace_dynevent.c tracing: Report wrong dynamic event command 2025-11-10 19:26:14 -05:00
trace_dynevent.h tracing: probes: Fix a possible race in trace_probe_log APIs 2025-05-13 22:23:34 +09:00
trace_entries.h ftrace: Expose call graph depth as unsigned int 2025-05-08 09:36:08 -04:00
trace_eprobe.c tracing: Have eprobes handle arrays 2025-07-24 22:57:32 +09:00
trace_event_perf.c perf: Remove unnecessary parameter of security check 2025-02-26 14:13:58 -05:00
trace_events_filter_test.h
trace_events_filter.c tracing changes for 6.17 2025-08-01 10:29:36 -07:00
trace_events_hist.c tracing: Rename event_trigger_alloc() to trigger_data_alloc() 2025-05-09 15:19:11 -04:00
trace_events_inject.c tracing: Have format file honor EVENT_FILE_FL_FREED 2024-08-07 18:12:46 -04:00
trace_events_synth.c tracing: Allow tracer to add more than 32 options 2025-11-04 21:44:00 +09:00
trace_events_trigger.c tracing updates for v6.16: 2025-05-29 21:04:36 -07:00
trace_events_user.c tracing updates for v6.18: 2025-10-05 09:43:36 -07:00
trace_events.c tracing: Allow tracer to add more than 32 options 2025-11-04 21:44:00 +09:00
trace_export.c tracing: Add back FORTIFY_SOURCE logic to kernel_stack event structure 2023-07-30 18:11:44 -04:00
trace_fprobe.c tracing: Allow tracer to add more than 32 options 2025-11-04 21:44:00 +09:00
trace_functions_graph.c tracing: Allow tracer to add more than 32 options 2025-11-04 21:44:00 +09:00
trace_functions.c tracing updates for v6.16: 2025-05-29 21:04:36 -07:00
trace_hwlat.c tracing: Replace opencoded cpumask_next_wrap() in move_to_next_cpu() 2025-07-08 18:17:29 -04:00
trace_irqsoff.c tracing: Allow tracer to add more than 32 options 2025-11-04 21:44:00 +09:00
trace_kdb.c tracing: Allow tracer to add more than 32 options 2025-11-04 21:44:00 +09:00
trace_kprobe_selftest.c tracing: arm64: Avoid missing-prototype warnings 2023-07-12 12:06:04 -04:00
trace_kprobe_selftest.h
trace_kprobe.c tracing: Allow tracer to add more than 32 options 2025-11-04 21:44:00 +09:00
trace_mmiotrace.c tracing/mmiotrace: Remove reference to unused per CPU data pointer 2025-05-08 09:36:09 -04:00
trace_nop.c
trace_osnoise.c tracing clean up and fixes for v6.18: 2025-10-09 12:18:22 -07:00
trace_output.c Merge branch 'topic/func-profiler-offset' of git://git.kernel.org/pub/scm/linux/kernel/git/mhiramat/linux into trace/trace/core 2025-11-04 10:12:32 -05:00
trace_output.h tracing: Allow tracer to add more than 32 options 2025-11-04 21:44:00 +09:00
trace_preemptirq.c tracing: Fix archs that still call tracepoints without RCU watching 2024-12-05 09:28:58 -05:00
trace_printk.c
trace_probe_kernel.h tracing/probes: Fix to record 0-length data_loc in fetch_store_string*() if fails 2023-07-14 17:04:58 +09:00
trace_probe_tmpl.h tracing/fprobe: Enable fprobe events with CONFIG_DYNAMIC_FTRACE_WITH_ARGS 2024-12-26 10:50:04 -05:00
trace_probe.c Probes updates for v6.17: 2025-07-30 15:38:01 -07:00
trace_probe.h tracing: Fix race condition in kprobe initialization causing NULL pointer dereference 2025-10-02 08:05:01 +09:00
trace_recursion_record.c
trace_sched_switch.c tracing: Ensure optimized hashing works 2025-09-30 17:27:58 -04:00
trace_sched_wakeup.c tracing: Allow tracer to add more than 32 options 2025-11-04 21:44:00 +09:00
trace_selftest_dynamic.c
trace_selftest.c fgraph: Pass ftrace_regs to retfunc 2024-12-26 10:50:03 -05:00
trace_seq.c trace_seq: Increase the buffer size to almost two pages 2023-12-18 23:14:16 -05:00
trace_stack.c tracing updates for v6.16: 2025-05-29 21:04:36 -07:00
trace_stat.c tracing: Switch trace_stat.c code over to use guard() 2024-12-26 10:38:37 -05:00
trace_stat.h
trace_synth.h tracing: Allow synthetic events to pass around stacktraces 2023-01-25 10:31:24 -05:00
trace_syscalls.c tracing: Hide __NR_utimensat and _NR_mq_timedsend when not defined 2025-11-10 14:23:53 -05:00
trace_uprobe.c tracing: Fix race condition in kprobe initialization causing NULL pointer dereference 2025-10-02 08:05:01 +09:00
trace.c tracing: Have tracer option be instance specific 2025-11-12 09:59:54 -05:00
trace.h tracing: Have tracer option be instance specific 2025-11-12 09:59:54 -05:00
tracing_map.c tracing: Use vmalloc_array() to improve code 2025-09-23 09:31:58 -04:00
tracing_map.h tracing: Remove unused extern declaration tracing_map_set_field_descr() 2023-07-23 11:08:14 -04:00