From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1758240Ab0EMBWr (ORCPT ); Wed, 12 May 2010 21:22:47 -0400 Received: from mail-wy0-f174.google.com ([74.125.82.174]:41117 "EHLO mail-wy0-f174.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1758153Ab0EMBVW (ORCPT ); Wed, 12 May 2010 21:21:22 -0400 DomainKey-Signature: a=rsa-sha1; c=nofws; d=gmail.com; s=gamma; h=from:to:cc:subject:date:message-id:x-mailer:x-mailer-version :in-reply-to:references; b=lGtETBMJyeEbFiS3inWMTm/q1Nd+sy6Ot1yB169CMRDGSOwsmOV+6q4EbLWLBCwbKn ywd8OgeLOQtMdpItMt8ek9V0XzxIxzpYAOpJrr6JSSR8/WqJrzkAplrbyIXANAuUz837 tFJ7eJH773kN/b03sz5mfnCKCTqBcC3Wsi+Hw= From: Frederic Weisbecker To: Ingo Molnar Cc: LKML , Don Zickus , Ingo Molnar , Peter Zijlstra , Cyrill Gorcunov , Eric Paris , Randy Dunlap , Frederic Weisbecker Subject: [PATCH 5/9] x86: Move trigger_all_cpu_backtrace to its own die_notifier Date: Thu, 13 May 2010 03:21:10 +0200 Message-Id: <1273713674-8434-6-git-send-regression-fweisbec@gmail.com> X-Mailer: git-send-regression X-Mailer-version: 0.1, "The maintainer couldn't reproduce after one week full time debugging" special version. In-Reply-To: <1273713674-8434-1-git-send-regression-fweisbec@gmail.com> References: <1273713674-8434-1-git-send-regression-fweisbec@gmail.com> Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org From: Don Zickus As part of the transition of the nmi watchdog to something more generic, the trigger_all_cpu_backtrace code is getting left behind. Put it in its own die_notifier so it can still be used. V2: - use arch_spin_locks Signed-off-by: Don Zickus Cc: Ingo Molnar Cc: Peter Zijlstra Cc: Cyrill Gorcunov Cc: Eric Paris Cc: Randy Dunlap LKML-Reference: <1273266711-18706-6-git-send-email-dzickus@redhat.com> Signed-off-by: Frederic Weisbecker --- arch/x86/kernel/apic/hw_nmi.c | 65 ++++++++++++++++++++++++++++++++--------- 1 files changed, 51 insertions(+), 14 deletions(-) diff --git a/arch/x86/kernel/apic/hw_nmi.c b/arch/x86/kernel/apic/hw_nmi.c index 79425f9..8c3edfb 100644 --- a/arch/x86/kernel/apic/hw_nmi.c +++ b/arch/x86/kernel/apic/hw_nmi.c @@ -17,6 +17,10 @@ #include #include #include +#include +#include +#include + #include #include @@ -54,20 +58,6 @@ int hw_nmi_is_cpu_stuck(struct pt_regs *regs) unsigned int sum; int cpu = smp_processor_id(); - /* FIXME: cheap hack for this check, probably should get its own - * die_notifier handler - */ - if (cpumask_test_cpu(cpu, to_cpumask(backtrace_mask))) { - static DEFINE_SPINLOCK(lock); /* Serialise the printks */ - - spin_lock(&lock); - printk(KERN_WARNING "NMI backtrace for cpu %d\n", cpu); - show_regs(regs); - dump_stack(); - spin_unlock(&lock); - cpumask_clear_cpu(cpu, to_cpumask(backtrace_mask)); - } - /* if we are doing an mce, just assume the cpu is not stuck */ /* Could check oops_in_progress here too, but it's safer not to */ if (mce_in_progress()) @@ -109,6 +99,53 @@ void arch_trigger_all_cpu_backtrace(void) mdelay(1); } } + +static int __kprobes +arch_trigger_all_cpu_backtrace_handler(struct notifier_block *self, + unsigned long cmd, void *__args) +{ + struct die_args *args = __args; + struct pt_regs *regs; + int cpu = smp_processor_id(); + + switch (cmd) { + case DIE_NMI: + case DIE_NMI_IPI: + break; + + default: + return NOTIFY_DONE; + } + + regs = args->regs; + + if (cpumask_test_cpu(cpu, to_cpumask(backtrace_mask))) { + static arch_spinlock_t lock = __ARCH_SPIN_LOCK_UNLOCKED; + + arch_spin_lock(&lock); + printk(KERN_WARNING "NMI backtrace for cpu %d\n", cpu); + show_regs(regs); + dump_stack(); + arch_spin_unlock(&lock); + cpumask_clear_cpu(cpu, to_cpumask(backtrace_mask)); + return NOTIFY_STOP; + } + + return NOTIFY_DONE; +} + +static __read_mostly struct notifier_block backtrace_notifier = { + .notifier_call = arch_trigger_all_cpu_backtrace_handler, + .next = NULL, + .priority = 1 +}; + +static int __init register_trigger_all_cpu_backtrace(void) +{ + register_die_notifier(&backtrace_notifier); + return 0; +} +early_initcall(register_trigger_all_cpu_backtrace); #endif /* STUB calls to mimic old nmi_watchdog behaviour */ -- 1.6.2.3