From mboxrd@z Thu Jan 1 00:00:00 1970 From: Sebastian Andrzej Siewior Subject: Re: [PATCH][RT] x86: Fix an RT MCE crash Date: Wed, 6 Jul 2016 15:43:51 +0200 Message-ID: <4eb7ab5c-447e-addc-be99-ce4b4682e4bb@linutronix.de> References: <20160630170134.GA3932@pd.tnic> <57755449.7070302@acm.org> <20160630172611.GC3932@pd.tnic> <57755CC6.60506@acm.org> <20160630182257.GD3932@pd.tnic> <577576AA.8040004@mvista.com> <20160630203457.GF3932@pd.tnic> <5775A181.2050404@acm.org> <20160701072050.GA4593@pd.tnic> <577C580F.8010004@acm.org> <20160706083704.GA7300@pd.tnic> <577CF39F.5010400@mvista.com> <20160706093256.29406f9b@gandalf.local.home> Mime-Version: 1.0 Content-Type: text/plain; charset=windows-1252 Content-Transfer-Encoding: 7bit Cc: Borislav Petkov , Corey Minyard , "Luck, Tony" , "linux-rt-users@vger.kernel.org" To: Steven Rostedt , Corey Minyard Return-path: Received: from www.linutronix.de ([62.245.132.108]:40012 "EHLO Galois.linutronix.de" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1754246AbcGFNn4 (ORCPT ); Wed, 6 Jul 2016 09:43:56 -0400 In-Reply-To: <20160706093256.29406f9b@gandalf.local.home> Sender: linux-rt-users-owner@vger.kernel.org List-ID: On 07/06/2016 03:32 PM, Steven Rostedt wrote: > On Wed, 6 Jul 2016 07:03:43 -0500 > Corey Minyard wrote: > >>> --- >>> diff --git a/arch/x86/kernel/cpu/mcheck/mce.c b/arch/x86/kernel/cpu/mcheck/mce.c >>> index aaf4b9b94f38..cc70d98a30f6 100644 >>> --- a/arch/x86/kernel/cpu/mcheck/mce.c >>> +++ b/arch/x86/kernel/cpu/mcheck/mce.c >>> @@ -1391,7 +1391,8 @@ static int mce_notify_work_init(void) >>> >>> static void mce_notify_work(void) >>> { >>> - wake_up_process(mce_notify_helper); >>> + if (mce_notify_helper) >>> + wake_up_process(mce_notify_helper); >>> } > > Actually, this appears to be the fix in 4.6-rt. This is in there since it was switched to swork instead of using its own thread and is also in v4.1: https://git.kernel.org/cgit/linux/kernel/git/rt/linux-rt-devel.git/tree/arch/x86/kernel/cpu/mcheck/mce.c?h=linux-4.1.y-rt#n1387 as part of x86-mce-use-swait-queue-for-mce-wakeups.patch. And this patch was first part of v3.18.9-rt4 as a new patch dropping x86-mce- Defer-mce-wakeups-to-threads-for-PREEMPT_RT.patch. > -- Steve Sebastian