diff options
authorStephane Eranian <eranian@google.com>2013-03-15 14:26:07 +0100
committerLinus Torvalds <torvalds@linux-foundation.org>2013-03-15 09:26:35 -0700
commit1d9d8639c063caf6efc2447f5f26aa637f844ff6 (patch)
parenta2362d24764a4e9a3187fc46b14e1d2cd0657700 (diff)
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>
3 files changed, 12 insertions, 0 deletions
diff --git a/arch/x86/kernel/cpu/perf_event_intel_ds.c b/arch/x86/kernel/cpu/perf_event_intel_ds.c
index 826054a4f2e..0e9bdd3cb01 100644
--- a/arch/x86/kernel/cpu/perf_event_intel_ds.c
+++ b/arch/x86/kernel/cpu/perf_event_intel_ds.c
@@ -729,3 +729,11 @@ void intel_ds_init(void)
+void perf_restore_debug_store(void)
+ if (!x86_pmu.bts && !x86_pmu.pebs)
+ return;
+ init_debug_store_on_cpu(smp_processor_id());
diff --git a/arch/x86/power/cpu.c b/arch/x86/power/cpu.c
index 120cee1c3f8..3c68768d7a7 100644
--- a/arch/x86/power/cpu.c
+++ b/arch/x86/power/cpu.c
@@ -11,6 +11,7 @@
#include <linux/suspend.h>
#include <linux/export.h>
#include <linux/smp.h>
+#include <linux/perf_event.h>
#include <asm/pgtable.h>
#include <asm/proto.h>
@@ -228,6 +229,7 @@ static void __restore_processor_state(struct saved_context *ctxt)
+ perf_restore_debug_store();
/* Needed by apm.c */
diff --git a/include/linux/perf_event.h b/include/linux/perf_event.h
index e47ee462c2f..71caed8626b 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);
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) { }
#define perf_output_put(handle, x) perf_output_copy((handle), &(x), sizeof(x))