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| author | Stephane Eranian <eranian@google.com> | 2013-03-15 14:26:07 +0100 |
|---|---|---|
| committer | Linus Torvalds <torvalds@linux-foundation.org> | 2013-03-15 09:26:35 -0700 |
| commit | 1d9d8639c063caf6efc2447f5f26aa637f844ff6 (patch) | |
| tree | ab9c24ccfd8b464211b393ac8ae9cd6b964e9df3 /include/linux/perf_event.h | |
| parent | a2362d24764a4e9a3187fc46b14e1d2cd0657700 (diff) | |
| download | lwn-1d9d8639c063caf6efc2447f5f26aa637f844ff6.tar.gz lwn-1d9d8639c063caf6efc2447f5f26aa637f844ff6.zip | |
perf,x86: fix kernel crash with PEBS/BTS after suspend/resume
This patch fixes a kernel crash when using precise sampling (PEBS)
after a suspend/resume. Turns out the CPU notifier code is not invoked
on CPU0 (BP). Therefore, the DS_AREA (used by PEBS) is not restored properly
by the kernel and keeps it power-on/resume value of 0 causing any PEBS
measurement to crash when running on CPU0.
The workaround is to add a hook in the actual resume code to restore
the DS Area MSR value. It is invoked for all CPUS. So for all but CPU0,
the DS_AREA will be restored twice but this is harmless.
Reported-by: Linus Torvalds <torvalds@linux-foundation.org>
Signed-off-by: Stephane Eranian <eranian@google.com>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Diffstat (limited to 'include/linux/perf_event.h')
| -rw-r--r-- | include/linux/perf_event.h | 2 |
1 files changed, 2 insertions, 0 deletions
diff --git a/include/linux/perf_event.h b/include/linux/perf_event.h index e47ee462c2f2..71caed8626be 100644 --- a/include/linux/perf_event.h +++ b/include/linux/perf_event.h @@ -758,6 +758,7 @@ extern void perf_event_enable(struct perf_event *event); extern void perf_event_disable(struct perf_event *event); extern int __perf_event_disable(void *info); extern void perf_event_task_tick(void); +extern void perf_restore_debug_store(void); #else static inline void perf_event_task_sched_in(struct task_struct *prev, @@ -797,6 +798,7 @@ static inline void perf_event_enable(struct perf_event *event) { } static inline void perf_event_disable(struct perf_event *event) { } static inline int __perf_event_disable(void *info) { return -1; } static inline void perf_event_task_tick(void) { } +static inline void perf_restore_debug_store(void) { } #endif #define perf_output_put(handle, x) perf_output_copy((handle), &(x), sizeof(x)) |