From mboxrd@z Thu Jan 1 00:00:00 1970 From: David Vrabel Subject: Re: [Xen-devel] [linux-3.14 bisection] complete test-amd64-i386-xl-qcow2 Date: Thu, 3 Sep 2015 12:16:39 +0100 Message-ID: <55E82C17.2070907@citrix.com> References: <1441099198.27618.13.camel@citrix.com> <21989.30329.419566.715627@mariner.uk.xensource.com> <1441101938.27618.17.camel@citrix.com> <1441185512.26292.111.camel@citrix.com> <20150903110554.GB2601@ares> Mime-Version: 1.0 Content-Type: text/plain; charset="utf-8" Content-Transfer-Encoding: 7bit Return-path: In-Reply-To: <20150903110554.GB2601@ares> Sender: stable-owner@vger.kernel.org To: Luis Henriques , Ian Campbell Cc: xen-devel@lists.xensource.com, Greg Kroah-Hartman , Ian Jackson , osstest service owner , stable@vger.kernel.org, =?UTF-8?B?TWFyZWsgTWFyY3p5a293c2tpLUfDs3JlY2tp?= , David Vrabel , Jiri Slaby List-Id: xen-devel@lists.xenproject.org On 03/09/15 12:05, Luis Henriques wrote: > On Wed, Sep 02, 2015 at 10:18:32AM +0100, Ian Campbell wrote: >> [resending to correct stable address, sorry folks] >> >> TL;DR: Any backport of 30b03d05e074 to earlier than commit 1401c00e59e >> ("xen/gntdev: convert priv->lock to a mutex", which was added in v4.0) >> needs $something doing to it, either s/mutex/spinlock/ or (more likely) >> backporting of 1401c00e59e too. >> >> Looking at LTS: >> >> 3.18.y: Backported both. >> 3.16.y: Has backported neither >> 3.14.y: * Only backported 30b03d05e074 >> 3.12.y: Has backported neither >> 3.10.y: * Only backported 30b03d05e074 >> 3.4.y: Has backported neither >> 3.2.y: Has backported neither >> >> So AFAICT 3.14.y and 3.10.y need fixes, probably following 3.18 and >> backporting 1401c00e59e. >> >> 3.16/12/4/2 might need to be careful if they subsequently pick up 30b03d05. >> > > Thank you Ian. In fact, I had explicitly dropped 30b03d05e074 > ("xen/gntdevt: Fix race condition in gntdev_release()") from the 3.16 > kernel and notified stable maintainers about this problem (in a reply to a > 3.12 review email). > > Simply replacing the mutex by the spinlock in this commit seems to cause > problems (sleep in atomic) as pointed out by Jiri in other thread. > > Since 1401c00e59ea ("xen/gntdev: convert priv->lock to a mutex") is a > clean cherry-pick for 3.16 (and probably to older kernels as well), I'm > happy to pick both commits if you can confirm they are both good for older > stable kernels (they seem to be!) You can take both 1401c00e59ea and 30b03d05e074. David