From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from list by lists.gnu.org with archive (Exim 4.71) id 1XHsPh-0000XD-R0 for mharc-qemu-trivial@gnu.org; Thu, 14 Aug 2014 06:37:45 -0400 Received: from eggs.gnu.org ([2001:4830:134:3::10]:47310) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1XHsPa-0000NK-LG for qemu-trivial@nongnu.org; Thu, 14 Aug 2014 06:37:43 -0400 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1XHsPV-0001pj-Re for qemu-trivial@nongnu.org; Thu, 14 Aug 2014 06:37:38 -0400 Received: from mx1.redhat.com ([209.132.183.28]:53112) by eggs.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1XHsPJ-0001mX-S8; Thu, 14 Aug 2014 06:37:22 -0400 Received: from int-mx10.intmail.prod.int.phx2.redhat.com (int-mx10.intmail.prod.int.phx2.redhat.com [10.5.11.23]) by mx1.redhat.com (8.14.4/8.14.4) with ESMTP id s7EAajw8008049 (version=TLSv1/SSLv3 cipher=DHE-RSA-AES256-GCM-SHA384 bits=256 verify=OK); Thu, 14 Aug 2014 06:36:45 -0400 Received: from redhat.com (ovpn-116-117.ams2.redhat.com [10.36.116.117]) by int-mx10.intmail.prod.int.phx2.redhat.com (8.14.4/8.14.4) with SMTP id s7EAafLk019948; Thu, 14 Aug 2014 06:36:41 -0400 Date: Thu, 14 Aug 2014 12:37:18 +0200 From: "Michael S. Tsirkin" To: zhanghailiang Message-ID: <20140814103718.GJ31346@redhat.com> References: <1408001361-13580-1-git-send-email-zhang.zhanghailiang@huawei.com> <1408001361-13580-4-git-send-email-zhang.zhanghailiang@huawei.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <1408001361-13580-4-git-send-email-zhang.zhanghailiang@huawei.com> X-Scanned-By: MIMEDefang 2.68 on 10.5.11.23 X-detected-operating-system: by eggs.gnu.org: GNU/Linux 3.x X-Received-From: 209.132.183.28 Cc: kwolf@redhat.com, lkurusa@redhat.com, qemu-trivial@nongnu.org, jan.kiszka@siemens.com, riku.voipio@iki.fi, mjt@tls.msk.ru, qemu-devel@nongnu.org, lcapitulino@redhat.com, stefanha@redhat.com, luonengjun@huawei.com, pbonzini@redhat.com, peter.huangpeng@huawei.com, alex.bennee@linaro.org, rth@twiddle.net Subject: Re: [Qemu-trivial] [PATCH v6 03/10] virtio-blk: fix reference a pointer which might be freed 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, 14 Aug 2014 10:37:43 -0000 On Thu, Aug 14, 2014 at 03:29:14PM +0800, zhanghailiang wrote: > In function virtio_blk_handle_request, it may freed memory pointed by req, > So do not access member of req after calling this function. > > Reviewed-by: Stefan Hajnoczi > Signed-off-by: zhanghailiang Reviewed-by: Michael S. Tsirkin Stefan want to pick up this one? > --- > hw/block/virtio-blk.c | 5 +++-- > 1 file changed, 3 insertions(+), 2 deletions(-) > > diff --git a/hw/block/virtio-blk.c b/hw/block/virtio-blk.c > index c241c50..54a853a 100644 > --- a/hw/block/virtio-blk.c > +++ b/hw/block/virtio-blk.c > @@ -458,7 +458,7 @@ static void virtio_blk_handle_output(VirtIODevice *vdev, VirtQueue *vq) > static void virtio_blk_dma_restart_bh(void *opaque) > { > VirtIOBlock *s = opaque; > - VirtIOBlockReq *req = s->rq; > + VirtIOBlockReq *req = s->rq, *next = NULL; > MultiReqBuffer mrb = { > .num_writes = 0, > }; > @@ -469,8 +469,9 @@ static void virtio_blk_dma_restart_bh(void *opaque) > s->rq = NULL; > > while (req) { > + next = req->next; > virtio_blk_handle_request(req, &mrb); > - req = req->next; > + req = next; > } > > virtio_submit_multiwrite(s->bs, &mrb); > -- > 1.7.12.4 >