Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1757122Ab3J1Oue (ORCPT ); Mon, 28 Oct 2013 10:50:34 -0400 Received: from mailout01.t-online.de ([194.25.134.80]:33046 "EHLO mailout01.t-online.de" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1757109Ab3J1Ou3 (ORCPT ); Mon, 28 Oct 2013 10:50:29 -0400 Message-ID: <526E79A2.9080303@t-online.de> Date: Mon, 28 Oct 2013 15:50:10 +0100 From: Knut Petersen User-Agent: Mozilla/5.0 (X11; Linux i686; rv:24.0) Gecko/20100101 Thunderbird/24.0 MIME-Version: 1.0 To: Ingo Molnar , Linus Torvalds CC: Thomas Gleixner , Paul McKenney , =?ISO-8859-1?Q?Fr=E9d=E9ric_Weisbecker?= , Greg KH , linux-kernel Subject: Re: [BUG 3.12.rc4] Oops: unable to handle kernel paging request during shutdown References: <525BD08C.2080101@t-online.de> <20131026114303.GA24067@gmail.com> In-Reply-To: <20131026114303.GA24067@gmail.com> Content-Type: text/plain; charset=ISO-8859-1; format=flowed Content-Transfer-Encoding: 7bit X-ID: ZASTkyZXrhUr34CKahQmpCe15l1HuRKhWcZ1icE+nStsFxnszfmd-y2ptF-Z9NPgSy X-TOI-MSGID: 307d3a79-6ae3-49a5-b73f-9ae0e1ea9973 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1961 Lines: 50 On 26.10.2013 13:43, Ingo Molnar wrote: > * Linus Torvalds wrote: > >> On Fri, Oct 25, 2013 at 11:23 AM, Thomas Gleixner wrote: >>> Enable DEBUG_OBJECTS, DEBUG_OBJECTS_FREE, DEBUG_OBJECTS_TIMERS >> Yes, but nobody has actually been able to trigger it with those. >> It's pretty rare, and the debug options are so expensive that they >> aren't reasonable to enable generally... >> >> So we need to try to figure out how to trigger it, or narrow >> things down some way.. > If it's timing then maybe the 1 seconds delay isn't enough > (especially if it's boot related, where we have a couple of delays > already) - the patch below triples it. > > (If the bug goes away due to some other side effect then this patch > won't make a difference to reproducability.) I tried that patch, together with all the kobj debug options enabled. With that kernel configuration I was unable to reproduce the problem during 500 typical workload / reboot cycles. Without the debug options I was able to reproduce the last reported panic after 91 cycles. The debug options seem to change timing sufficiently to mask the bug ;-( Knut > Thanks, > > Ingo > > diff --git a/lib/kobject.c b/lib/kobject.c > index 084f7b1..124188f 100644 > --- a/lib/kobject.c > +++ b/lib/kobject.c > @@ -595,7 +595,7 @@ static void kobject_release(struct kref *kref) > pr_info("kobject: '%s' (%p): %s, parent %p (delayed)\n", > kobject_name(kobj), kobj, __func__, kobj->parent); > INIT_DELAYED_WORK(&kobj->release, kobject_delayed_cleanup); > - schedule_delayed_work(&kobj->release, HZ); > + schedule_delayed_work(&kobj->release, 3*HZ); > #else > kobject_cleanup(kobj); > #endif > -- 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/