Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1751829Ab3FYRVe (ORCPT ); Tue, 25 Jun 2013 13:21:34 -0400 Received: from hrndva-omtalb.mail.rr.com ([71.74.56.122]:27744 "EHLO hrndva-omtalb.mail.rr.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751191Ab3FYRVc (ORCPT ); Tue, 25 Jun 2013 13:21:32 -0400 X-Authority-Analysis: v=2.0 cv=KtrPKBqN c=1 sm=0 a=rXTBtCOcEpjy1lPqhTCpEQ==:17 a=mNMOxpOpBa8A:10 a=XqNnylozy48A:10 a=5SG0PmZfjMsA:10 a=IkcTkHD0fZMA:10 a=meVymXHHAAAA:8 a=KGjhK52YXX0A:10 a=pkicDPhlfI0A:10 a=YXVxBQmCVOTLb6hAWYYA:9 a=QEXdDO2ut3YA:10 a=rXTBtCOcEpjy1lPqhTCpEQ==:117 X-Cloudmark-Score: 0 X-Authenticated-User: X-Originating-IP: 74.67.115.198 Message-ID: <1372180890.18733.217.camel@gandalf.local.home> Subject: Re: frequent softlockups with 3.10rc6. From: Steven Rostedt To: Dave Jones Cc: Oleg Nesterov , "Paul E. McKenney" , Linux Kernel , Linus Torvalds , "Eric W. Biederman" , Andrey Vagin Date: Tue, 25 Jun 2013 13:21:30 -0400 In-Reply-To: <20130625165556.GA16170@redhat.com> References: <20130623143634.GA2000@redhat.com> <20130623150603.GA32313@redhat.com> <20130623160452.GA11740@redhat.com> <20130624020014.GB12811@redhat.com> <20130624143928.GA20659@redhat.com> <1372085549.18733.162.camel@gandalf.local.home> <20130624160012.GB5993@redhat.com> <1372091079.18733.168.camel@gandalf.local.home> <20130624165140.GB8572@redhat.com> <1372093476.18733.170.camel@gandalf.local.home> <20130625165556.GA16170@redhat.com> Content-Type: text/plain; charset="UTF-8" X-Mailer: Evolution 3.4.4-3 Mime-Version: 1.0 Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1023 Lines: 27 On Tue, 2013-06-25 at 12:55 -0400, Dave Jones wrote: > While I've been spinning wheels trying to reproduce that softlockup bug, > On another machine I've been refining my list-walk debug patch. > I added an ugly "ok, the ringbuffer is playing games with lower two bits" special case. > > But what the hell is going on here ? > > next->prev should be prev (ffff88023c6cdd18), but was 00ffff88023c6cdd. (next=ffff880243288001). > > (trace comes from the same ringbuffer code) What's the above saying? ffff880243288000->prev == 00ffff88023c6cdd but it should have been ffff88023c6cdd18? That is: ffff88023c6cdd18->next == ffff880243288001? Not sure how that would mess up. The ring-buffer code has lots of integrity checks to make sure nothing like this breaks. -- Steve -- 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/