From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from eggs.gnu.org ([2001:4830:134:3::10]:54492) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1ZYzHO-00042W-Qf for qemu-devel@nongnu.org; Mon, 07 Sep 2015 12:28:27 -0400 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1ZYzHJ-0004I8-IY for qemu-devel@nongnu.org; Mon, 07 Sep 2015 12:28:26 -0400 References: <55BB2DF7.8010808@kamp.de> <55BB302D.50108@redhat.com> <55BB335A.1010009@kamp.de> <55BB3FE7.3000106@redhat.com> <55E846F4.7000506@kamp.de> From: Paolo Bonzini Message-ID: <55EDBB21.1090400@redhat.com> Date: Mon, 7 Sep 2015 18:28:17 +0200 MIME-Version: 1.0 In-Reply-To: <55E846F4.7000506@kamp.de> Content-Type: text/plain; charset=utf-8 Content-Transfer-Encoding: 7bit Subject: Re: [Qemu-devel] [Qemu-stable] Recent patches for 2.4 List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , To: Peter Lieven , Stefan Hajnoczi Cc: "qemu-devel@nongnu.org" , qemu-stable@nongnu.org On 03/09/2015 15:11, Peter Lieven wrote: >> >>>>> edec47c main-loop: fix qemu_notify_event for aio_notify optimization >>>> Part of the above AioContext series. >>> So either the whole series or none of them I guess? >> It's a separate bug, and theoretically it's there in 2.3.1 as well, but >> no one ever reproduced it (it would hang in make check) so not >> worthwhile. > > I maybe found another case where this bugfix seems to help. For various > reasons I'm still on 2.2.1 stable with some CVE fixes manually applied. Don't be ashamed to say that! :) > I currently work on the problem that a haning NFS Server where I mount > my CDROM ISOs from takes down the whole vServer because the main loop > hangs sooner or later. > > I already put some patches on the list which help to improve the situation: > > ide/atapi: make PIO read requests async > block/io: allow AIOCB without callback > ide/atapi: partially avoid deadlock if the storage backend is dead > block/nfs: cache allocated filesize for read-only files > > However, I ended up with one case where Qemu deadlocks in bdrv_drain_one. > > Scenario: > - Windows 2012R2 with a random ISO mounted. > - Block communication to NFS via Firewall > - execute 'eject ide1-cd0' in the HMP > - restore connectivity. > > The HMP hangs forever even if the NFS connectivity itself is restored. If that patch helps, it's not a problem to include it in other stable releases. Paolo