Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1756759Ab3CRVLl (ORCPT ); Mon, 18 Mar 2013 17:11:41 -0400 Received: from mail-qc0-f174.google.com ([209.85.216.174]:46572 "EHLO mail-qc0-f174.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S932448Ab3CRVL3 (ORCPT ); Mon, 18 Mar 2013 17:11:29 -0400 MIME-Version: 1.0 In-Reply-To: <20130318210512.334023372@linuxfoundation.org> References: <20130318210510.203500214@linuxfoundation.org> <20130318210512.334023372@linuxfoundation.org> Date: Mon, 18 Mar 2013 22:11:28 +0100 Message-ID: Subject: Re: [ 29/75] perf,x86: fix kernel crash with PEBS/BTS after suspend/resume From: Stephane Eranian To: Greg Kroah-Hartman Cc: LKML , stable@vger.kernel.org, Linus Torvalds Content-Type: text/plain; charset=UTF-8 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 3427 Lines: 91 On Mon, Mar 18, 2013 at 10:06 PM, Greg Kroah-Hartman wrote: > 3.8-stable review patch. If anyone has any objections, please let me know. > Greg, you also need to pick David Rientjes patch to fix compilation on non X86 architectures. Thanks. > ------------------ > > From: Stephane Eranian > > 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 > Signed-off-by: Stephane Eranian > Signed-off-by: Linus Torvalds > Signed-off-by: Greg Kroah-Hartman > > --- > 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(+) > > --- 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()); > +} > --- a/arch/x86/power/cpu.c > +++ b/arch/x86/power/cpu.c > @@ -11,6 +11,7 @@ > #include > #include > #include > +#include > > #include > #include > @@ -228,6 +229,7 @@ static void __restore_processor_state(st > do_fpu_end(); > x86_platform.restore_sched_clock_state(); > mtrr_bp_restore(); > + perf_restore_debug_store(); > } > > /* Needed by apm.c */ > --- a/include/linux/perf_event.h > +++ b/include/linux/perf_event.h > @@ -753,6 +753,7 @@ extern void perf_event_enable(struct per > 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, > @@ -792,6 +793,7 @@ static inline void perf_event_enable(str > 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)) > > -- 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/