From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1755175AbcEBUyl (ORCPT ); Mon, 2 May 2016 16:54:41 -0400 Received: from mail.linuxfoundation.org ([140.211.169.12]:54839 "EHLO mail.linuxfoundation.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753488AbcEBUyd (ORCPT ); Mon, 2 May 2016 16:54:33 -0400 Date: Mon, 2 May 2016 13:54:31 -0700 From: "gregkh@linuxfoundation.org" To: Steven Haigh Cc: Boris Ostrovsky , xen-devel , linux-kernel@vger.kernel.org Subject: Re: 4.4: INFO: rcu_sched self-detected stall on CPU Message-ID: <20160502205431.GA14983@kroah.com> References: <56F52DBF.5080006@oracle.com> <56F545B1.8080609@crc.id.au> <56F54EE0.6030004@oracle.com> <56F56172.9020805@crc.id.au> <56F5653B.1090700@oracle.com> <56F5A87A.8000903@crc.id.au> <56FA4336.2030301@crc.id.au> <56FA8DDD.7070406@oracle.com> <56FABF17.7090608@crc.id.au> <56FAC3AC.9050802@crc.id.au> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <56FAC3AC.9050802@crc.id.au> User-Agent: Mutt/1.6.0 (2016-04-01) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Wed, Mar 30, 2016 at 05:04:28AM +1100, Steven Haigh wrote: > Greg, please see below - this is probably more for you... > > On 03/29/2016 04:56 AM, Steven Haigh wrote: > > > > Interestingly enough, this just happened again - but on a different > > virtual machine. I'm starting to wonder if this may have something to do > > with the uptime of the machine - as the system that this seems to happen > > to is always different. > > > > Destroying it and monitoring it again has so far come up blank. > > > > I've thrown the latest lot of kernel messages here: > > http://paste.fedoraproject.org/346802/59241532 > > So I just did a bit of digging via the almighty Google. > > I started hunting for these lines, as they happen just before the stall: > BUG: Bad rss-counter state mm:ffff88007b7db480 idx:2 val:-1 > BUG: Bad rss-counter state mm:ffff880079c638c0 idx:0 val:-1 > BUG: Bad rss-counter state mm:ffff880079c638c0 idx:2 val:-1 > > I stumbled across this post on the lkml: > http://marc.info/?l=linux-kernel&m=145141546409607 > > The patch attached seems to reference the following change in > unmap_mapping_range in mm/memory.c: > > - struct zap_details details; > > + struct zap_details details = { }; > > When I browse the GIT tree for 4.4.6: > https://git.kernel.org/cgit/linux/kernel/git/stable/linux-stable.git/tree/mm/memory.c?id=refs/tags/v4.4.6 > > I see at line 2411: > struct zap_details details; > > Is this something that has been missed being merged into the 4.4 tree? > I'll admit my kernel knowledge is not enough to understand what the code > actually does - but the similarities here seem uncanny. I'm sorry, I have no idea what you are asking me about here. Did I miss a patch that should be backported? Did I backport something incorrectly? confused, greg k-h