Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1755525Ab3CRVGx (ORCPT ); Mon, 18 Mar 2013 17:06:53 -0400 Received: from mail.linuxfoundation.org ([140.211.169.12]:45573 "EHLO mail.linuxfoundation.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1755490Ab3CRVGu (ORCPT ); Mon, 18 Mar 2013 17:06:50 -0400 From: Greg Kroah-Hartman To: linux-kernel@vger.kernel.org Cc: Greg Kroah-Hartman , stable@vger.kernel.org, Linus Torvalds , Stephane Eranian Subject: [ 29/75] perf,x86: fix kernel crash with PEBS/BTS after suspend/resume Date: Mon, 18 Mar 2013 14:06:52 -0700 Message-Id: <20130318210512.334023372@linuxfoundation.org> X-Mailer: git-send-email 1.8.1.2.434.g9a6c84e.dirty In-Reply-To: <20130318210510.203500214@linuxfoundation.org> References: <20130318210510.203500214@linuxfoundation.org> User-Agent: quilt/0.60-1 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 2949 Lines: 86 3.8-stable review patch. If anyone has any objections, please let me know. ------------------ 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/