Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1755526Ab3CPA6K (ORCPT ); Fri, 15 Mar 2013 20:58:10 -0400 Received: from g6t0185.atlanta.hp.com ([15.193.32.62]:8451 "EHLO g6t0185.atlanta.hp.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1755031Ab3CPA6I (ORCPT ); Fri, 15 Mar 2013 20:58:08 -0400 Message-ID: <1363395478.7231.9.camel@lorien2> Subject: [PATCH 3.0] perf,x86: fix kernel crash with PEBS/BTS after suspend/resume From: Shuah Khan Reply-To: shuah.khan@hp.com To: eranian@google.com, Greg KH , a.p.zijlstra@chello.nl, paulus@samba.org, mingo@elte.hu, acme@ghostprotocols.net, tglx@linutronix.de, hpa@zytor.com, pavel@ucw.cz, rafael.j.wysocki@intel.com Cc: LKML , torvalds@linux-foundation.org, peterz@infradead.org, Andrew Morton , jolsa@redhat.com, ak@linux.intel.com, stable , shuahkhan@gmail.com Date: Fri, 15 Mar 2013 18:57:58 -0600 Organization: ISS-Linux Content-Type: text/plain; charset="UTF-8" X-Mailer: Evolution 3.2.3-0ubuntu6 Content-Transfer-Encoding: 7bit Mime-Version: 1.0 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 3254 Lines: 92 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. Upstream commit id: 1d9d8639c063caf6efc2447f5f26aa637f844ff6 Reported-by: Linus Torvalds Signed-off-by: Stephane Eranian Signed-off-by: Linus Torvalds Signed-off-by: Shuah Khan CC: stable@vger.kernel.org 3.0 --- arch/x86/kernel/cpu/perf_event_intel_ds.c | 8 ++++++++ arch/x86/power/cpu.c | 2 ++ include/linux/perf_event.h | 2 ++ 3 files changed, 12 insertions(+) diff --git a/arch/x86/kernel/cpu/perf_event_intel_ds.c b/arch/x86/kernel/cpu/perf_event_intel_ds.c index d812fe2..cf82ee5 100644 --- a/arch/x86/kernel/cpu/perf_event_intel_ds.c +++ b/arch/x86/kernel/cpu/perf_event_intel_ds.c @@ -754,6 +754,14 @@ static 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()); +} + #else /* CONFIG_CPU_SUP_INTEL */ static void reserve_ds_buffers(void) diff --git a/arch/x86/power/cpu.c b/arch/x86/power/cpu.c index 87bb35e..0ea8bd2 100644 --- a/arch/x86/power/cpu.c +++ b/arch/x86/power/cpu.c @@ -10,6 +10,7 @@ #include #include +#include #include #include @@ -224,6 +225,7 @@ static void __restore_processor_state(struct saved_context *ctxt) do_fpu_end(); mtrr_bp_restore(); + perf_restore_debug_store(); } /* Needed by apm.c */ diff --git a/include/linux/perf_event.h b/include/linux/perf_event.h index effadd6..038ad4a 100644 --- a/include/linux/perf_event.h +++ b/include/linux/perf_event.h @@ -1153,6 +1153,7 @@ extern void perf_swevent_put_recursion_context(int rctx); extern void perf_event_enable(struct perf_event *event); extern void perf_event_disable(struct perf_event *event); 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 *task) { } @@ -1187,6 +1188,7 @@ static inline void perf_swevent_put_recursion_context(int rctx) { } static inline void perf_event_enable(struct perf_event *event) { } static inline void perf_event_disable(struct perf_event *event) { } 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)) -- 1.7.9.5 -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/