From nobody Wed Nov 12 05:23:19 2025 Delivered-To: importer@patchew.org Received-SPF: pass (zoho.com: domain of gnu.org designates 209.51.188.17 as permitted sender) client-ip=209.51.188.17; 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 209.51.188.17 as permitted sender) smtp.mailfrom=qemu-devel-bounces+importer=patchew.org@nongnu.org; dmarc=fail(p=none dis=none) header.from=redhat.com ARC-Seal: i=1; a=rsa-sha256; t=1568297803; cv=none; d=zoho.com; s=zohoarc; b=lct38+RREPQkVkcrZQ13hk7TDTh+3W1ZVc+Bjy4fyfU0MNECeGKBij6ivlhFEDxOvKE/xkOj5h9L64ZBhHzy5BwkYI8M3pF7oV5friVaiJQR4WFZ/dmhhJTvvfvWzmKfnfBXasBTOfaqUuzBVbPP3cD7DNq2ZgNfXV27YZX7+gE= ARC-Message-Signature: i=1; a=rsa-sha256; c=relaxed/relaxed; d=zoho.com; s=zohoarc; t=1568297803; h=Content-Transfer-Encoding:Cc:Date:From:In-Reply-To:List-Subscribe:List-Post:List-Id:List-Archive:List-Help:List-Unsubscribe:MIME-Version:Message-ID:References:Sender:Subject:To:ARC-Authentication-Results; bh=g7Lj8dP6AodYq1TBvCHjDIJ1mHmX0yZ6cbDc/U8LZVw=; b=CbrmKzToEXWEPwSOUgmCjwCWhLdIWNwZs179GxRct3N+Y8zzAllOjQ11Xe63WGqIym0v7o5q59q/rtksoXCA8A1Xg2QsUKfz1S+am6NZeSAHyuXoBDJqi/YP9eqX6v4Dj8DShVkPhb1MonItDU9xgv4mmtppRLBldwgkFLxW9qY= ARC-Authentication-Results: i=1; mx.zoho.com; spf=pass (zoho.com: domain of gnu.org designates 209.51.188.17 as permitted sender) smtp.mailfrom=qemu-devel-bounces+importer=patchew.org@nongnu.org; dmarc=fail header.from= (p=none dis=none) header.from= Return-Path: Received: from lists.gnu.org (lists.gnu.org [209.51.188.17]) by mx.zohomail.com with SMTPS id 15682978031056.572772240601125; Thu, 12 Sep 2019 07:16:43 -0700 (PDT) Received: from localhost ([::1]:34980 helo=lists1p.gnu.org) by lists.gnu.org with esmtp (Exim 4.90_1) (envelope-from ) id 1i8Ptp-00017Y-0i for importer@patchew.org; Thu, 12 Sep 2019 10:16:41 -0400 Received: from eggs.gnu.org ([2001:470:142:3::10]:41682) by lists.gnu.org with esmtp (Exim 4.90_1) (envelope-from ) id 1i8PaX-0006Uu-Ba for qemu-devel@nongnu.org; Thu, 12 Sep 2019 09:56:46 -0400 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1i8PaW-0006NE-9P for qemu-devel@nongnu.org; Thu, 12 Sep 2019 09:56:45 -0400 Received: from mx1.redhat.com ([209.132.183.28]:34690) by eggs.gnu.org with esmtps (TLS1.0:DHE_RSA_AES_256_CBC_SHA1:32) (Exim 4.71) (envelope-from ) id 1i8PaU-0006Lj-2q; Thu, 12 Sep 2019 09:56:42 -0400 Received: from smtp.corp.redhat.com (int-mx01.intmail.prod.int.phx2.redhat.com [10.5.11.11]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by mx1.redhat.com (Postfix) with ESMTPS id 6D60F8E581; Thu, 12 Sep 2019 13:56:41 +0000 (UTC) Received: from localhost (unknown [10.40.205.22]) by smtp.corp.redhat.com (Postfix) with ESMTPS id A29AE600C4; Thu, 12 Sep 2019 13:56:40 +0000 (UTC) From: Max Reitz To: qemu-block@nongnu.org Date: Thu, 12 Sep 2019 15:56:29 +0200 Message-Id: <20190912135632.13925-2-mreitz@redhat.com> In-Reply-To: <20190912135632.13925-1-mreitz@redhat.com> References: <20190912135632.13925-1-mreitz@redhat.com> MIME-Version: 1.0 X-Scanned-By: MIMEDefang 2.79 on 10.5.11.11 X-Greylist: Sender IP whitelisted, not delayed by milter-greylist-4.5.16 (mx1.redhat.com [10.5.110.28]); Thu, 12 Sep 2019 13:56:41 +0000 (UTC) Content-Transfer-Encoding: quoted-printable 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 1/4] mirror: Do not dereference invalid pointers X-BeenThere: qemu-devel@nongnu.org X-Mailman-Version: 2.1.23 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Cc: Kevin Wolf , John Snow , qemu-devel@nongnu.org, Markus Armbruster , Max Reitz Errors-To: qemu-devel-bounces+importer=patchew.org@nongnu.org Sender: "Qemu-devel" Content-Type: text/plain; charset="utf-8" mirror_exit_common() may be called twice (if it is called from mirror_prepare() and fails, it will be called from mirror_abort() again). In such a case, many of the pointers in the MirrorBlockJob object will already be freed. This can be seen most reliably for s->target, which is set to NULL (and then dereferenced by blk_bs()). Cc: qemu-stable@nongnu.org Fixes: 737efc1eda23b904fbe0e66b37715fb0e5c3e58b Signed-off-by: Max Reitz Reviewed-by: John Snow Reviewed-by: Vladimir Sementsov-Ogievskiy --- block/mirror.c | 13 +++++++++---- 1 file changed, 9 insertions(+), 4 deletions(-) diff --git a/block/mirror.c b/block/mirror.c index fe984efb90..706d80fced 100644 --- a/block/mirror.c +++ b/block/mirror.c @@ -620,11 +620,11 @@ static int mirror_exit_common(Job *job) { MirrorBlockJob *s =3D container_of(job, MirrorBlockJob, common.job); BlockJob *bjob =3D &s->common; - MirrorBDSOpaque *bs_opaque =3D s->mirror_top_bs->opaque; + MirrorBDSOpaque *bs_opaque; AioContext *replace_aio_context =3D NULL; - BlockDriverState *src =3D s->mirror_top_bs->backing->bs; - BlockDriverState *target_bs =3D blk_bs(s->target); - BlockDriverState *mirror_top_bs =3D s->mirror_top_bs; + BlockDriverState *src; + BlockDriverState *target_bs; + BlockDriverState *mirror_top_bs; Error *local_err =3D NULL; bool abort =3D job->ret < 0; int ret =3D 0; @@ -634,6 +634,11 @@ static int mirror_exit_common(Job *job) } s->prepared =3D true; =20 + mirror_top_bs =3D s->mirror_top_bs; + bs_opaque =3D mirror_top_bs->opaque; + src =3D mirror_top_bs->backing->bs; + target_bs =3D blk_bs(s->target); + if (bdrv_chain_contains(src, target_bs)) { bdrv_unfreeze_backing_chain(mirror_top_bs, target_bs); } --=20 2.21.0