From mboxrd@z Thu Jan 1 00:00:00 1970 From: Steven Rostedt Subject: Re: [PATCH][RT] x86: Fix an RT MCE crash Date: Thu, 30 Jun 2016 09:43:01 -0400 Message-ID: <20160630094301.22d32ec1@gandalf.local.home> References: <1467293089-27656-1-git-send-email-minyard@acm.org> Mime-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 7bit Cc: linux-rt-users@vger.kernel.org, Corey Minyard To: minyard@acm.org Return-path: Received: from smtprelay0086.hostedemail.com ([216.40.44.86]:53676 "EHLO smtprelay.hostedemail.com" rhost-flags-OK-OK-OK-FAIL) by vger.kernel.org with ESMTP id S1751994AbcF3NnF (ORCPT ); Thu, 30 Jun 2016 09:43:05 -0400 In-Reply-To: <1467293089-27656-1-git-send-email-minyard@acm.org> Sender: linux-rt-users-owner@vger.kernel.org List-ID: On Thu, 30 Jun 2016 08:24:49 -0500 minyard@acm.org wrote: > From: Corey Minyard > > On some x86 systems an MCE interrupt would come in before the kernel > was ready for it. Looking at the latest RT code, it has similar > (but not quite the same) code, except it adds a bool that tells if > MCE handling is initialized. Add the same bool for older versions. > > Signed-off-by: Corey Minyard > --- > arch/x86/kernel/cpu/mcheck/mce.c | 5 ++++- > 1 file changed, 4 insertions(+), 1 deletion(-) > > We noticed this issue on a new Broadwell system when we booted RT > on it. This patch is for 3.10, I'm not sure if it applies to > other kernel versions. Do you mean other 'older' versions? and that this works with the versions after 3.10 without this patch? -- Steve > > diff --git a/arch/x86/kernel/cpu/mcheck/mce.c b/arch/x86/kernel/cpu/mcheck/mce.c > index aaf4b9b..7125584 100644 > --- a/arch/x86/kernel/cpu/mcheck/mce.c > +++ b/arch/x86/kernel/cpu/mcheck/mce.c > @@ -1365,6 +1365,7 @@ static void __mce_notify_work(void) > } > > #ifdef CONFIG_PREEMPT_RT_FULL > +static bool notify_work_ready __read_mostly; > struct task_struct *mce_notify_helper; > > static int mce_notify_helper_thread(void *unused) > @@ -1386,12 +1387,14 @@ static int mce_notify_work_init(void) > if (!mce_notify_helper) > return -ENOMEM; > > + notify_work_ready = true; > return 0; > } > > static void mce_notify_work(void) > { > - wake_up_process(mce_notify_helper); > + if (notify_work_ready) > + wake_up_process(mce_notify_helper); > } > #else > static void mce_notify_work(void)