From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from eggs.gnu.org ([2001:4830:134:3::10]:49771) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1ZZ1pS-00022W-Kx for qemu-devel@nongnu.org; Mon, 07 Sep 2015 15:11:47 -0400 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1ZZ1pN-0005ft-Lb for qemu-devel@nongnu.org; Mon, 07 Sep 2015 15:11:46 -0400 Received: from mx-v6.kamp.de ([2a02:248:0:51::16]:42499 helo=mx01.kamp.de) by eggs.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1ZZ1pN-0005dZ-BA for qemu-devel@nongnu.org; Mon, 07 Sep 2015 15:11:41 -0400 Message-ID: <55EDE167.6050400@kamp.de> Date: Mon, 07 Sep 2015 21:11:35 +0200 From: Peter Lieven MIME-Version: 1.0 References: <55BB2DF7.8010808@kamp.de> <55BB302D.50108@redhat.com> <55BB335A.1010009@kamp.de> <55BB3FE7.3000106@redhat.com> <55E846F4.7000506@kamp.de> <55EDBB21.1090400@redhat.com> In-Reply-To: <55EDBB21.1090400@redhat.com> 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: Paolo Bonzini , Stefan Hajnoczi Cc: "qemu-devel@nongnu.org" , qemu-stable@nongnu.org Am 07.09.2015 um 18:28 schrieb Paolo Bonzini: > > 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. It helps, but I have a small issue when my backport of the patch is applied. I launch qemu witch a cmdline like this to probe for enforcable CPU types. echo quit | qemu -enable-kvm -monitor stdio -nodefaults -nographic -cpu Haswell,enforce -S Qemu hangs when entering the quit command. If I omit the -S it works. And without the fix it also works with -S. My backport (Linux only and without tests etc.) of the original fix is here: https://github.com/plieven/qemu/commit/0ddcdc62a85f705017df16421d769e82b70f9b37 Maybe I made a mistake. Peter