From 1d9d8639c063caf6efc2447f5f26aa637f844ff6 Mon Sep 17 00:00:00 2001 From: Stephane Eranian Date: Fri, 15 Mar 2013 14:26:07 +0100 Subject: 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 Signed-off-by: Stephane Eranian Signed-off-by: Linus Torvalds --- include/linux/perf_event.h | 2 ++ 1 file changed, 2 insertions(+) (limited to 'include/linux/perf_event.h') 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)) -- cgit v1.2.3-59-g8ed1b From 6c4d3bc99b3341067775efd4d9d13cc8e655fd7c Mon Sep 17 00:00:00 2001 From: David Rientjes Date: Sun, 17 Mar 2013 15:49:10 -0700 Subject: perf,x86: fix link failure for non-Intel configs Commit 1d9d8639c063 ("perf,x86: fix kernel crash with PEBS/BTS after suspend/resume") introduces a link failure since perf_restore_debug_store() is only defined for CONFIG_CPU_SUP_INTEL: arch/x86/power/built-in.o: In function `restore_processor_state': (.text+0x45c): undefined reference to `perf_restore_debug_store' Fix it by defining the dummy function appropriately. Signed-off-by: David Rientjes Cc: stable@vger.kernel.org Signed-off-by: Linus Torvalds --- include/linux/perf_event.h | 6 +++++- 1 file changed, 5 insertions(+), 1 deletion(-) (limited to 'include/linux/perf_event.h') diff --git a/include/linux/perf_event.h b/include/linux/perf_event.h index 71caed8626be..1d795df6f4cf 100644 --- a/include/linux/perf_event.h +++ b/include/linux/perf_event.h @@ -758,7 +758,6 @@ 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, @@ -798,6 +797,11 @@ 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) { } +#endif + +#if defined(CONFIG_PERF_EVENTS) && defined(CONFIG_CPU_SUP_INTEL) +extern void perf_restore_debug_store(void); +#else static inline void perf_restore_debug_store(void) { } #endif -- cgit v1.2.3-59-g8ed1b