Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752217AbaKZFY4 (ORCPT ); Wed, 26 Nov 2014 00:24:56 -0500 Received: from cantor2.suse.de ([195.135.220.15]:59272 "EHLO mx2.suse.de" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752041AbaKZFYy (ORCPT ); Wed, 26 Nov 2014 00:24:54 -0500 Message-ID: <54756424.6020409@suse.com> Date: Wed, 26 Nov 2014 06:24:52 +0100 From: Juergen Gross User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:31.0) Gecko/20100101 Thunderbird/31.2.0 MIME-Version: 1.0 To: Linus Torvalds CC: the arch/x86 maintainers , Kernel Mailing List , Dave Jones Subject: Re: frequent lockups in 3.18rc4 References: <20141114213124.GB3344@redhat.com> <20141115213405.GA31971@redhat.com> <20141116014006.GA5016@redhat.com> <20141126002501.GA11752@redhat.com> <5475596A.9010301@suse.com> In-Reply-To: Content-Type: text/plain; charset=utf-8; format=flowed Content-Transfer-Encoding: 8bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On 11/26/2014 06:09 AM, Linus Torvalds wrote: > > On Nov 25, 2014 8:39 PM, "Jürgen Groß" > wrote: > > > > I COULD trigger it with 3.17. Took much longer, but I've seen it once. > > And from Xen hypervisor data it was clear it was the same bug (cpu > > spinning in pmd_lock()). > > I'm still hoping you can give a back trace. I'd like to know what access > it is that can trigger this, and preferably what the call chain to it was... Working on it. Triggering it via sysrq(l) isn't working: machine hung up. I'll try a dump, but this might take some time due to the machine size... If this isn't working I can always modify the hypervisor to show me more of the kernel stack in that situation. This will be a pure dump, but it should be possible to extract the back trace from that. > > I do believe it happened in 3.17, I just want to understand the but more > - not just apply the fix.. Sure. > > Most of Dave's lockup back traces did not have the whole page fault in > them, so while Dave has seen this too, there might be different symptoms... Stay tuned... :-) Juergen -- 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/