From mboxrd@z Thu Jan  1 00:00:00 1970
Received: from eggs.gnu.org ([2001:4830:134:3::10]:56215)
	by lists.gnu.org with esmtp (Exim 4.71)
	(envelope-from <famz@redhat.com>) id 1YpSpA-00067Z-5c
	for qemu-devel@nongnu.org; Mon, 04 May 2015 22:43:09 -0400
Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71)
	(envelope-from <famz@redhat.com>) id 1YpSp9-0001UC-13
	for qemu-devel@nongnu.org; Mon, 04 May 2015 22:43:08 -0400
Date: Tue, 5 May 2015 10:42:56 +0800
From: Fam Zheng <famz@redhat.com>
Message-ID: <20150505024256.GD31965@ad.nay.redhat.com>
References: <1430140709-13599-1-git-send-email-famz@redhat.com>
	<20150430133452.GB25594@noname.redhat.com>
MIME-Version: 1.0
Content-Type: text/plain; charset=us-ascii
Content-Disposition: inline
In-Reply-To: <20150430133452.GB25594@noname.redhat.com>
Subject: Re: [Qemu-devel] [PATCH v4 0/3] block: Fix unaligned
 bdrv_aio_write_zeroes
List-Id: <qemu-devel.nongnu.org>
List-Unsubscribe: <https://lists.nongnu.org/mailman/options/qemu-devel>,
	<mailto:qemu-devel-request@nongnu.org?subject=unsubscribe>
List-Archive: <http://lists.nongnu.org/archive/html/qemu-devel>
List-Post: <mailto:qemu-devel@nongnu.org>
List-Help: <mailto:qemu-devel-request@nongnu.org?subject=help>
List-Subscribe: <https://lists.nongnu.org/mailman/listinfo/qemu-devel>,
	<mailto:qemu-devel-request@nongnu.org?subject=subscribe>
To: Kevin Wolf <kwolf@redhat.com>
Cc: pbonzini@redhat.com, Stefan Hajnoczi <stefanha@redhat.com>, qemu-devel@nongnu.org, qemu-block@nongnu.org, qemu-stable@nongnu.org

On Thu, 04/30 15:34, Kevin Wolf wrote:
> Am 27.04.2015 um 15:18 hat Fam Zheng geschrieben:
> > An unaligned zero write causes NULL deferencing in bdrv_co_do_pwritev. That
> > path is reachable from bdrv_co_write_zeroes and bdrv_aio_write_zeroes.
> > 
> > You can easily trigger through the former with qemu-io, as the test case added
> > by 61815d6e0aa. For bdrv_aio_write_zeroes, in common cases there's always a
> > format driver (which uses 512 alignment), so it would be much rarer to have
> > unaligned requests (only concerning top level here, when the request goes down
> > to bs->file, where for example the alignment is 4k, it would then be calling
> > bdrv_co_write_zeroes because it's in a coroutine).
> > 
> > fc3959e4669a1c fixed bdrv_co_write_zeroes but not bdrv_aio_write_zeroes.  The
> > lattern is the actually used one by device model. Revert the previous fix, do
> > it in bdrv_co_do_pwritev, to cover both paths.
> 
> Hi Fam,
> 
> Stefan's patch to split out block/io.c conflicts with this. Can you
> please rebase?

I'll do it.

Fam

> 
> Kevin
>