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Wed, 1 Apr 2020 18:44:39 +0000 (UTC) Received: from linux.fritz.box (ovpn-114-172.ams2.redhat.com [10.36.114.172]) by smtp.corp.redhat.com (Postfix) with ESMTPS id A74F95D9CD; Wed, 1 Apr 2020 18:44:32 +0000 (UTC) Date: Wed, 1 Apr 2020 20:44:31 +0200 From: Kevin Wolf To: Dietmar Maurer Subject: Re: bdrv_drained_begin deadlock with io-threads Message-ID: <20200401184431.GD27663@linux.fritz.box> References: <20200331125804.GE7030@linux.fritz.box> <303038276.59.1585665152860@webmail.proxmox.com> <787d7517-bf56-72c7-d197-2313a864e05f@virtuozzo.com> <713436887.61.1585668262838@webmail.proxmox.com> <20200331153719.GI7030@linux.fritz.box> <518198448.62.1585671498399@webmail.proxmox.com> <20200401103748.GA4680@linux.fritz.box> <997901084.0.1585755465486@webmail.proxmox.com> <20200401181256.GB27663@linux.fritz.box> <1403939459.52.1585765681569@webmail.proxmox.com> MIME-Version: 1.0 In-Reply-To: <1403939459.52.1585765681569@webmail.proxmox.com> User-Agent: Mutt/1.12.1 (2019-06-15) X-Scanned-By: MIMEDefang 2.79 on 10.5.11.14 X-Mimecast-Spam-Score: 0 X-Mimecast-Originator: redhat.com Content-Type: text/plain; charset=us-ascii Content-Transfer-Encoding: quoted-printable Content-Disposition: inline X-detected-operating-system: by eggs.gnu.org: GNU/Linux 2.2.x-3.x [generic] X-Received-From: 205.139.110.61 X-BeenThere: qemu-devel@nongnu.org X-Mailman-Version: 2.1.23 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Cc: Vladimir Sementsov-Ogievskiy , qemu-block@nongnu.org, Sergio Lopez , "qemu-devel@nongnu.org" , Max Reitz , Stefan Hajnoczi , "jsnow@redhat.com" Errors-To: qemu-devel-bounces+qemu-devel=archiver.kernel.org@nongnu.org Sender: "Qemu-devel" Am 01.04.2020 um 20:28 hat Dietmar Maurer geschrieben: > > That's a pretty big change, and I'm not sure how it's related to > > completed requests hanging in the thread pool instead of reentering the > > file-posix coroutine. But I also tested it enough that I'm confident > > it's really the first bad commit. > >=20 > > Maybe you want to try if your problem starts at the same commit? >=20 > Stefan already found that by bisecting last week: >=20 > See: https://lists.gnu.org/archive/html/qemu-devel/2020-03/msg07629.html >=20 > But, IMHO the commit is not the reason for (my) bug - It just makes > it easier to trigger... I can see (my) bug sometimes with 4.1.1, although > I have no easy way to reproduce it reliable. >=20 > Also, Stefan sent some patches to the list to fix some of the problems. >=20 > https://lists.gnu.org/archive/html/qemu-devel/2020-04/msg00022.html >=20 > Does that fix your problem? It seems to fix it, yes. Now I don't get any hangs any more. (Also, I guess this means that this day was essentially wasted because I worked on a problem that already has a fix... *sigh*) Kevin