From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1755031Ab0DUVK5 (ORCPT ); Wed, 21 Apr 2010 17:10:57 -0400 Received: from mx1.redhat.com ([209.132.183.28]:26894 "EHLO mx1.redhat.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1754344Ab0DUVKz (ORCPT ); Wed, 21 Apr 2010 17:10:55 -0400 Date: Wed, 21 Apr 2010 17:10:12 -0400 From: Don Zickus To: Frederic Weisbecker Cc: mingo@elte.hu, peterz@infradead.org, gorcunov@gmail.com, aris@redhat.com, linux-kernel@vger.kernel.org, randy.dunlap@oracle.com Subject: Re: [PATCH 5/6] [x86] watchdog: move trigger_all_cpu_backtrace to its own die_notifier Message-ID: <20100421211012.GX15159@redhat.com> References: <1271777043-3807-1-git-send-email-dzickus@redhat.com> <1271777043-3807-6-git-send-email-dzickus@redhat.com> <20100421210003.GC8677@nowhere> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20100421210003.GC8677@nowhere> User-Agent: Mutt/1.5.20 (2009-08-17) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Wed, Apr 21, 2010 at 11:00:04PM +0200, Frederic Weisbecker wrote: > On Tue, Apr 20, 2010 at 11:24:02AM -0400, Don Zickus wrote: > > 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. > > > > Signed-off-by: Don Zickus > > --- > > 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..19d3435 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 DEFINE_SPINLOCK(lock); /* Serialise the printks */ > > + > > + spin_lock(&lock); > > > > This should be an arch_spin_lock(), so that it won't sleep with rt mutex. ok, I just copied and pasted what was there currently. > > > In fact this whole function can be moved to generic code, right? generic for x86, yes. Ingo stuck in the nmi.c code awhile ago. This code just needs a home somewhere. I really don't care where. Cheers, Don