From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from list by lists.gnu.org with archive (Exim 4.71) id 1TOq6a-0004La-JX for mharc-qemu-trivial@gnu.org; Thu, 18 Oct 2012 09:25:44 -0400 Received: from eggs.gnu.org ([208.118.235.92]:47182) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1TOq6U-00044T-IK for qemu-trivial@nongnu.org; Thu, 18 Oct 2012 09:25:42 -0400 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1TOq6Q-0006m7-Hk for qemu-trivial@nongnu.org; Thu, 18 Oct 2012 09:25:38 -0400 Received: from cantor2.suse.de ([195.135.220.15]:36967 helo=mx2.suse.de) by eggs.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1TOq6M-0006lA-IY; Thu, 18 Oct 2012 09:25:30 -0400 Received: from relay1.suse.de (unknown [195.135.220.254]) (using TLSv1 with cipher DHE-RSA-AES256-SHA (256/256 bits)) (No client certificate requested) by mx2.suse.de (Postfix) with ESMTP id B8CB8A37E0; Thu, 18 Oct 2012 15:25:28 +0200 (CEST) Message-ID: <50800309.5040706@suse.de> Date: Thu, 18 Oct 2012 15:24:25 +0200 From: =?ISO-8859-1?Q?Andreas_F=E4rber?= Organization: SUSE LINUX Products GmbH User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:16.0) Gecko/20121010 Thunderbird/16.0.1 MIME-Version: 1.0 To: Kevin Wolf References: <1350220128-10140-1-git-send-email-thardeck@suse.de> <1350220128-10140-3-git-send-email-thardeck@suse.de> <507EC7FF.90603@suse.de> <1359569.y3MYGdvym5@thinktank.site> <507FDD38.2010009@redhat.com> In-Reply-To: <507FDD38.2010009@redhat.com> X-Enigmail-Version: 1.5a1pre Content-Type: text/plain; charset=ISO-8859-1 Content-Transfer-Encoding: quoted-printable X-detected-operating-system: by eggs.gnu.org: GNU/Linux 2.4-2.6 X-Received-From: 195.135.220.15 Cc: qemu-trivial , Tim Hardeck , qemu-devel@nongnu.org Subject: Re: [Qemu-trivial] [Qemu-devel] [PATCH 2/2] qemu queue: fix uninitialized removals X-BeenThere: qemu-trivial@nongnu.org X-Mailman-Version: 2.1.14 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Thu, 18 Oct 2012 13:25:42 -0000 Am 18.10.2012 12:43, schrieb Kevin Wolf: > Am 17.10.2012 23:24, schrieb Tim Hardeck: >> On Wednesday 17 October 2012 17:00:15 Andreas F=E4rber wrote: >>> Am 14.10.2012 15:08, schrieb Tim Hardeck: >>>> When calling QTAILQ_REMOVE or QLIST_REMOVE on an unitialized list >>>> QEMU segfaults. >>> >>> Can this be reproduced by a user today? Or is this just fixing the ca= se >>> that a developer forgot to initialize a list? >> I am not sure but in this case it happened during an early VNC connect= ion=20 >> state failure which most likely wouldn't happen to regular users. >> I triggered it while working on the VNC connection part. >> >> The issue could most likely be also fixed in the VNC connection initia= lization=20 >> process but if this changes doesn't have a relevant performance impact= they=20 >> might prevent some other/future crashes. >=20 > At the same time, it could be hiding real bugs, where ignoring the > QLIST_REMOVE() isn't the right fix. I can see your point, but I would b= e > careful with making interfaces less strict. What I don't get is, why is avoiding a NULL pointer dereference any better from accessing random memory through an uninitialized pointer? Or am I getting "uninitialized" wrong? > In any case, I don't think this qualifies for qemu-trivial, Andreas. Maybe not, but we don't have a clear maintainer that I'm aware of, and no one else reviewed it for several days before I did. ;) Andreas --=20 SUSE LINUX Products GmbH, Maxfeldstr. 5, 90409 N=FCrnberg, Germany GF: Jeff Hawn, Jennifer Guild, Felix Imend=F6rffer; HRB 16746 AG N=FCrnbe= rg From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from eggs.gnu.org ([208.118.235.92]:47151) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1TOq6P-0003wa-BJ for qemu-devel@nongnu.org; Thu, 18 Oct 2012 09:25:34 -0400 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1TOq6M-0006lT-SG for qemu-devel@nongnu.org; Thu, 18 Oct 2012 09:25:33 -0400 Message-ID: <50800309.5040706@suse.de> Date: Thu, 18 Oct 2012 15:24:25 +0200 From: =?ISO-8859-1?Q?Andreas_F=E4rber?= MIME-Version: 1.0 References: <1350220128-10140-1-git-send-email-thardeck@suse.de> <1350220128-10140-3-git-send-email-thardeck@suse.de> <507EC7FF.90603@suse.de> <1359569.y3MYGdvym5@thinktank.site> <507FDD38.2010009@redhat.com> In-Reply-To: <507FDD38.2010009@redhat.com> Content-Type: text/plain; charset=ISO-8859-1 Content-Transfer-Encoding: quoted-printable Subject: Re: [Qemu-devel] [PATCH 2/2] qemu queue: fix uninitialized removals List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , To: Kevin Wolf Cc: qemu-trivial , Tim Hardeck , qemu-devel@nongnu.org Am 18.10.2012 12:43, schrieb Kevin Wolf: > Am 17.10.2012 23:24, schrieb Tim Hardeck: >> On Wednesday 17 October 2012 17:00:15 Andreas F=E4rber wrote: >>> Am 14.10.2012 15:08, schrieb Tim Hardeck: >>>> When calling QTAILQ_REMOVE or QLIST_REMOVE on an unitialized list >>>> QEMU segfaults. >>> >>> Can this be reproduced by a user today? Or is this just fixing the ca= se >>> that a developer forgot to initialize a list? >> I am not sure but in this case it happened during an early VNC connect= ion=20 >> state failure which most likely wouldn't happen to regular users. >> I triggered it while working on the VNC connection part. >> >> The issue could most likely be also fixed in the VNC connection initia= lization=20 >> process but if this changes doesn't have a relevant performance impact= they=20 >> might prevent some other/future crashes. >=20 > At the same time, it could be hiding real bugs, where ignoring the > QLIST_REMOVE() isn't the right fix. I can see your point, but I would b= e > careful with making interfaces less strict. What I don't get is, why is avoiding a NULL pointer dereference any better from accessing random memory through an uninitialized pointer? Or am I getting "uninitialized" wrong? > In any case, I don't think this qualifies for qemu-trivial, Andreas. Maybe not, but we don't have a clear maintainer that I'm aware of, and no one else reviewed it for several days before I did. ;) Andreas --=20 SUSE LINUX Products GmbH, Maxfeldstr. 5, 90409 N=FCrnberg, Germany GF: Jeff Hawn, Jennifer Guild, Felix Imend=F6rffer; HRB 16746 AG N=FCrnbe= rg