diff options
| author | Stephane Eranian <eranian@google.com> | 2013-03-15 14:26:07 +0100 |
|---|---|---|
| committer | Ben Hutchings <ben@decadent.org.uk> | 2013-03-27 02:40:54 +0000 |
| commit | 8da1a618f37700141f1cf6e3a9c16dc1b1e261c9 (patch) | |
| tree | 93c90365323a03b14ef17bafb64aa0a39cf2d852 /arch | |
| parent | dc71dd5c5bd96038a90f4efc0c127e21ea86bba1 (diff) | |
| download | lwn-8da1a618f37700141f1cf6e3a9c16dc1b1e261c9.tar.gz lwn-8da1a618f37700141f1cf6e3a9c16dc1b1e261c9.zip | |
perf,x86: fix kernel crash with PEBS/BTS after suspend/resume
commit 1d9d8639c063caf6efc2447f5f26aa637f844ff6 upstream.
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>
Signed-off-by: Ben Hutchings <ben@decadent.org.uk>
Diffstat (limited to 'arch')
| -rw-r--r-- | arch/x86/kernel/cpu/perf_event_intel_ds.c | 8 | ||||
| -rw-r--r-- | arch/x86/power/cpu.c | 2 |
2 files changed, 10 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 73da6b64f5b7..41a7d21a098f 100644 --- a/arch/x86/kernel/cpu/perf_event_intel_ds.c +++ b/arch/x86/kernel/cpu/perf_event_intel_ds.c @@ -736,3 +736,11 @@ 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 f10c0afa1cb4..43c9f6aee486 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> @@ -225,6 +226,7 @@ static void __restore_processor_state(struct saved_context *ctxt) do_fpu_end(); mtrr_bp_restore(); + perf_restore_debug_store(); } /* Needed by apm.c */ |