Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1758093AbaKSWUE (ORCPT ); Wed, 19 Nov 2014 17:20:04 -0500 Received: from mx1.redhat.com ([209.132.183.28]:59901 "EHLO mx1.redhat.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1756991AbaKSWUA (ORCPT ); Wed, 19 Nov 2014 17:20:00 -0500 Date: Wed, 19 Nov 2014 17:18:19 -0500 From: Dave Jones To: Linus Torvalds Cc: Andy Lutomirski , Don Zickus , Thomas Gleixner , Linux Kernel , the arch/x86 maintainers , Peter Zijlstra , =?iso-8859-1?Q?Fr=E9d=E9ric?= Weisbecker , Arnaldo Carvalho de Melo Subject: Re: frequent lockups in 3.18rc4 Message-ID: <20141119221819.GA24195@redhat.com> Mail-Followup-To: Dave Jones , Linus Torvalds , Andy Lutomirski , Don Zickus , Thomas Gleixner , Linux Kernel , the arch/x86 maintainers , Peter Zijlstra , =?iso-8859-1?Q?Fr=E9d=E9ric?= Weisbecker , Arnaldo Carvalho de Melo References: <20141118145234.GA7487@redhat.com> <20141118215540.GD35311@redhat.com> <20141119021902.GA14216@redhat.com> <20141119145902.GA13387@redhat.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: User-Agent: Mutt/1.5.23 (2014-03-12) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Wed, Nov 19, 2014 at 11:38:09AM -0800, Linus Torvalds wrote: > > Is it possible that we've managed to return to userspace with > > interrupts off somehow? A loop in userspace that somehow has > > interrupts off can cause all kinds of fun lockups. > > That sounds unlikely, but if there is some stack corruption going on. > > However, it wouldn't even explain things, because even if interrupts > had been disabled in user space, and even if that popf got executed, > this wouldn't be where they got enabled. That would be the :"sti" in > the system call entry path (hidden behind the ENABLE_INTERRUPTS > macro). > > Of course, maybe Dave has paravirtualization enabled (what a crock > _that_ is), and there is something wrong with that whole code. I've had HYPERVISOR_GUEST disabled for a while, which also disables the paravirt code afaics. Dave -- 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/