github-mirror/linux
1
0
Fork 0
mirror of https://github.com/torvalds/linux.git synced 2026-06-08 14:42:37 +02:00
Code Issues Actions Packages Projects Releases Wiki Activity Graph
Linux kernel source tree
784,676 Commits 1 Branch 934 Tags 20 GiB
C 97%
Assembly 1%
Shell 0.6%
Rust 0.5%
Python 0.4%
Other 0.3%
205af59e70
Go to file
Jiri Olsa 205af59e70 perf/x86/intel: Disallow precise_ip on BTS events 
commit 472de49fdc upstream.

Vince reported a crash in the BTS flush code when touching the callchain
data, which was supposed to be initialized as an 'early' callchain,
but intel_pmu_drain_bts_buffer() does not do that:

  BUG: unable to handle kernel NULL pointer dereference at 0000000000000000
  ...
  Call Trace:
   <IRQ>
   intel_pmu_drain_bts_buffer+0x151/0x220
   ? intel_get_event_constraints+0x219/0x360
   ? perf_assign_events+0xe2/0x2a0
   ? select_idle_sibling+0x22/0x3a0
   ? __update_load_avg_se+0x1ec/0x270
   ? enqueue_task_fair+0x377/0xdd0
   ? cpumask_next_and+0x19/0x20
   ? load_balance+0x134/0x950
   ? check_preempt_curr+0x7a/0x90
   ? ttwu_do_wakeup+0x19/0x140
   x86_pmu_stop+0x3b/0x90
   x86_pmu_del+0x57/0x160
   event_sched_out.isra.106+0x81/0x170
   group_sched_out.part.108+0x51/0xc0
   __perf_event_disable+0x7f/0x160
   event_function+0x8c/0xd0
   remote_function+0x3c/0x50
   flush_smp_call_function_queue+0x35/0xe0
   smp_call_function_single_interrupt+0x3a/0xd0
   call_function_single_interrupt+0xf/0x20
   </IRQ>

It was triggered by fuzzer but can be easily reproduced by:

  # perf record -e cpu/branch-instructions/pu -g -c 1

Peter suggested not to allow branch tracing for precise events:

 > Now arguably, this is really stupid behaviour. Who in his right mind
 > wants callchain output on BTS entries. And even if they do, BTS +
 > precise_ip is nonsensical.
 >
 > So in my mind disallowing precise_ip on BTS would be the simplest fix.

Suggested-by: Peter Zijlstra <peterz@infradead.org>
Reported-by: Vince Weaver <vincent.weaver@maine.edu>
Signed-off-by: Jiri Olsa <jolsa@kernel.org>
Acked-by: Peter Zijlstra <a.p.zijlstra@chello.nl>
Cc: <stable@vger.kernel.org>
Cc: Alexander Shishkin <alexander.shishkin@linux.intel.com>
Cc: Arnaldo Carvalho de Melo <acme@kernel.org>
Cc: Arnaldo Carvalho de Melo <acme@redhat.com>
Cc: Jiri Olsa <jolsa@redhat.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Stephane Eranian <eranian@google.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Fixes: 6cbc304f2f ("perf/x86/intel: Fix unwind errors from PEBS entries (mk-II)")
Link: http://lkml.kernel.org/r/20181121101612.16272-3-jolsa@kernel.org
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2018-12-05 19:32:08 +01:00
arch perf/x86/intel: Disallow precise_ip on BTS events 2018-12-05 19:32:08 +01:00
block block: copy ioprio in __bio_clone_fast() and bounce 2018-12-01 09:37:32 +01:00
certs export.h: remove VMLINUX_SYMBOL() and VMLINUX_SYMBOL_STR() 2018-08-22 23:21:44 +09:00
crypto crypto: simd - correctly take reqsize of wrapped skcipher into account 2018-12-01 09:37:32 +01:00
Documentation x86/speculation: Provide IBPB always command line options 2018-12-05 19:32:04 +01:00
drivers PCI: Fix incorrect value returned from pcie_get_speed_cap() 2018-12-05 19:32:07 +01:00
firmware kbuild: remove all dummy assignments to obj- 2017-11-18 11:46:06 +09:00
fs btrfs: relocation: set trans to be NULL after ending transaction 2018-12-05 19:32:07 +01:00
include x86/speculation: Add prctl() control for indirect branch speculation 2018-12-05 19:32:04 +01:00
init Kbuild updates for v4.19 (2nd) 2018-08-25 13:40:38 -07:00
ipc ipc/shm.c: use ERR_CAST() for shm_lock() error return 2018-10-05 16:32:04 -07:00
kernel ptrace: Remove unused ptrace_may_access_sched() and MODE_IBRS 2018-12-05 19:32:03 +01:00
lib lib/raid6: Fix arm64 test build 2018-11-27 16:13:05 +01:00
LICENSES LICENSES: Remove CC-BY-SA-4.0 license text 2018-10-18 11:28:50 +02:00
mm userfaultfd: shmem/hugetlbfs: only allow to register VM_MAYWRITE vmas 2018-12-05 19:32:04 +01:00
net tipc: fix lockdep warning during node delete 2018-12-05 19:32:00 +01:00
samples samples: disable CONFIG_SAMPLES for UML 2018-10-11 02:15:46 +09:00
scripts x86/retpoline: Make CONFIG_RETPOLINE depend on compiler support 2018-12-05 19:32:01 +01:00
security selinux: Add __GFP_NOWARN to allocation at str_read() 2018-12-01 09:37:27 +01:00
sound ALSA: oss: Use kvzalloc() for local buffer allocations 2018-12-01 09:37:25 +01:00
tools x86/speculation: Add prctl() control for indirect branch speculation 2018-12-05 19:32:04 +01:00
usr initramfs: move gen_initramfs_list.sh from scripts/ to usr/ 2018-08-22 23:21:44 +09:00
virt KVM: arm64: Fix caching of host MDCR_EL2 value 2018-11-13 11:08:47 -08:00
.clang-format clang-format: Set IndentWrappedFunctionNames false 2018-08-01 18:38:51 +02:00
.cocciconfig
.get_maintainer.ignore
.gitattributes .gitattributes: set git diff driver for C source code files 2016-10-07 18:46:30 -07:00
.gitignore Kbuild updates for v4.17 (2nd) 2018-04-15 17:21:30 -07:00
.mailmap libnvdimm-for-4.19_misc 2018-08-25 18:13:10 -07:00
COPYING COPYING: use the new text with points to the license files 2018-03-23 12:41:45 -06:00
CREDITS 9p: remove Ron Minnich from MAINTAINERS 2018-08-17 16:20:26 -07:00
Kbuild Kbuild updates for v4.15 2017-11-17 17:45:29 -08:00
Kconfig kconfig: move the "Executable file formats" menu to fs/Kconfig.binfmt 2018-08-02 08:06:55 +09:00
MAINTAINERS MAINTAINERS: Add Sasha as a stable branch maintainer 2018-12-01 09:37:25 +01:00
Makefile Linux 4.19.6 2018-12-01 09:37:35 +01:00
README Docs: Added a pointer to the formatted docs to README 2018-03-21 09:02:53 -06:00

README 

Linux kernel
============

There are several guides for kernel developers and users. These guides can
be rendered in a number of formats, like HTML and PDF. Please read
Documentation/admin-guide/README.rst first.

In order to build the documentation, use ``make htmldocs`` or
``make pdfdocs``.  The formatted documentation can also be read online at:

    https://www.kernel.org/doc/html/latest/

There are various text files in the Documentation/ subdirectory,
several of them using the Restructured Text markup notation.
See Documentation/00-INDEX for a list of what is contained in each file.

Please read the Documentation/process/changes.rst file, as it contains the
requirements for building and running the kernel, and information about
the problems which may result by upgrading your kernel.