From nobody Wed Nov 5 20:00:14 2025 Delivered-To: importer@patchew.org Received-SPF: pass (zoho.com: domain of gnu.org designates 208.118.235.17 as permitted sender) client-ip=208.118.235.17; envelope-from=qemu-devel-bounces+importer=patchew.org@nongnu.org; helo=lists.gnu.org; Authentication-Results: mx.zohomail.com; spf=pass (zoho.com: domain of gnu.org designates 208.118.235.17 as permitted sender) smtp.mailfrom=qemu-devel-bounces+importer=patchew.org@nongnu.org; dmarc=fail(p=none dis=none) header.from=redhat.com Return-Path: Received: from lists.gnu.org (lists.gnu.org [208.118.235.17]) by mx.zohomail.com with SMTPS id 1536844292386603.0916922440285; Thu, 13 Sep 2018 06:11:32 -0700 (PDT) Received: from localhost ([::1]:42376 helo=lists.gnu.org) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1g0RP9-0007xL-1a for importer@patchew.org; Thu, 13 Sep 2018 09:11:31 -0400 Received: from eggs.gnu.org ([2001:4830:134:3::10]:47065) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1g0R7a-0002cR-2L for qemu-devel@nongnu.org; Thu, 13 Sep 2018 08:53:22 -0400 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1g0R7U-00029A-VH for qemu-devel@nongnu.org; Thu, 13 Sep 2018 08:53:21 -0400 Received: from mx1.redhat.com ([209.132.183.28]:43774) by eggs.gnu.org with esmtps (TLS1.0:DHE_RSA_AES_256_CBC_SHA1:32) (Exim 4.71) (envelope-from ) id 1g0R7S-00026m-DI; Thu, 13 Sep 2018 08:53:14 -0400 Received: from smtp.corp.redhat.com (int-mx02.intmail.prod.int.phx2.redhat.com [10.5.11.12]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by mx1.redhat.com (Postfix) with ESMTPS id B0FEB30E5F83; Thu, 13 Sep 2018 12:53:13 +0000 (UTC) Received: from localhost.localdomain.com (ovpn-117-67.ams2.redhat.com [10.36.117.67]) by smtp.corp.redhat.com (Postfix) with ESMTP id 5CB1760BE5; Thu, 13 Sep 2018 12:53:11 +0000 (UTC) From: Kevin Wolf To: qemu-block@nongnu.org Date: Thu, 13 Sep 2018 14:52:12 +0200 Message-Id: <20180913125217.23173-13-kwolf@redhat.com> In-Reply-To: <20180913125217.23173-1-kwolf@redhat.com> References: <20180913125217.23173-1-kwolf@redhat.com> X-Scanned-By: MIMEDefang 2.79 on 10.5.11.12 X-Greylist: Sender IP whitelisted, not delayed by milter-greylist-4.5.16 (mx1.redhat.com [10.5.110.45]); Thu, 13 Sep 2018 12:53:13 +0000 (UTC) X-detected-operating-system: by eggs.gnu.org: GNU/Linux 2.2.x-3.x [generic] X-Received-From: 209.132.183.28 Subject: [Qemu-devel] [PATCH v2 12/17] mirror: Fix potential use-after-free in active commit X-BeenThere: qemu-devel@nongnu.org X-Mailman-Version: 2.1.21 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Cc: kwolf@redhat.com, famz@redhat.com, slp@redhat.com, qemu-devel@nongnu.org, mreitz@redhat.com, pbonzini@redhat.com, jsnow@redhat.com Errors-To: qemu-devel-bounces+importer=patchew.org@nongnu.org Sender: "Qemu-devel" X-ZohoMail: RDMRC_1 RSF_0 Z_629925259 SPT_0 Content-Transfer-Encoding: quoted-printable MIME-Version: 1.0 Content-Type: text/plain; charset="utf-8" When starting an active commit job, other callbacks can run before mirror_start_job() calls bdrv_ref() where needed and cause the nodes to go away. Add another pair of bdrv_ref/unref() around it to protect against this case. Signed-off-by: Kevin Wolf --- block/mirror.c | 11 +++++++++++ 1 file changed, 11 insertions(+) diff --git a/block/mirror.c b/block/mirror.c index 56d9ef7474..c8657991cf 100644 --- a/block/mirror.c +++ b/block/mirror.c @@ -1697,7 +1697,14 @@ void commit_active_start(const char *job_id, BlockDr= iverState *bs, =20 orig_base_flags =3D bdrv_get_flags(base); =20 + /* bdrv_reopen() drains, which might make the BDSes go away before a + * reference is taken in mirror_start_job(). */ + bdrv_ref(bs); + bdrv_ref(base); + if (bdrv_reopen(base, bs->open_flags, errp)) { + bdrv_unref(bs); + bdrv_unref(base); return; } =20 @@ -1707,6 +1714,10 @@ void commit_active_start(const char *job_id, BlockDr= iverState *bs, &commit_active_job_driver, false, base, auto_complete, filter_node_name, false, MIRROR_COPY_MODE_BACKGROUND, &local_err); + + bdrv_unref(bs); + bdrv_unref(base); + if (local_err) { error_propagate(errp, local_err); goto error_restore_flags; --=20 2.13.6