From nobody Mon Feb 9 00:55:26 2026 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=1571067757; cv=none; d=zoho.com; s=zohoarc; b=Vp3wez2rcU0L1UiTapuIjQkBg4TLIwMygPSLR/C1XyuPu88d0qGYQ4lT2jmjMNR5LIGUN/Ts0PZCmXSOea7mCTG16ORbyBGVxhhZseRVqwmtSywSYfNDOz+94qmm5oDRksPFMjNCEZ4UsWLlj9Gu/JP/AIHqLDtNJbIkCqmnMkU= ARC-Message-Signature: i=1; a=rsa-sha256; c=relaxed/relaxed; d=zoho.com; s=zohoarc; t=1571067757; 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; bh=F45PXWKM5Ac1xd2K17PN60D0xKmTHDIWsREJRfGkgBE=; b=PjXawGEwyVEvym5wuAQGmqQMLm5iwgMxusgYOwNGeFAEFYguYtQbxEhaHzmA2jtS6ZYjUx/Iyey3l/4SLJp/UTwkdbbD/fh4i8VSBwKGusYWXsaaRbChxc/3fuM5dl39s87qOZex8Qtzq4GCS9ESpf5mDDQIbRBeIsC46qZTfbQ= 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 1571067757851650.5270787479899; Mon, 14 Oct 2019 08:42:37 -0700 (PDT) Received: from localhost ([::1]:51680 helo=lists1p.gnu.org) by lists.gnu.org with esmtp (Exim 4.90_1) (envelope-from ) id 1iK2UU-0001BF-Ju for importer@patchew.org; Mon, 14 Oct 2019 11:42:34 -0400 Received: from eggs.gnu.org ([2001:470:142:3::10]:60954) by lists.gnu.org with esmtp (Exim 4.90_1) (envelope-from ) id 1iK2Rp-0005vP-OR for qemu-devel@nongnu.org; Mon, 14 Oct 2019 11:39:50 -0400 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1iK2Ro-0004Cn-ME for qemu-devel@nongnu.org; Mon, 14 Oct 2019 11:39:49 -0400 Received: from mx1.redhat.com ([209.132.183.28]:62420) by eggs.gnu.org with esmtps (TLS1.0:DHE_RSA_AES_256_CBC_SHA1:32) (Exim 4.71) (envelope-from ) id 1iK2Rm-0004Ao-D0; Mon, 14 Oct 2019 11:39:46 -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 885ACC049E1A; Mon, 14 Oct 2019 15:39:45 +0000 (UTC) Received: from localhost (ovpn-117-165.ams2.redhat.com [10.36.117.165]) by smtp.corp.redhat.com (Postfix) with ESMTPS id 9A05D60BE2; Mon, 14 Oct 2019 15:39:39 +0000 (UTC) From: Max Reitz To: qemu-block@nongnu.org Subject: [PATCH v3 1/4] mirror: Do not dereference invalid pointers Date: Mon, 14 Oct 2019 17:39:28 +0200 Message-Id: <20191014153931.20699-2-mreitz@redhat.com> In-Reply-To: <20191014153931.20699-1-mreitz@redhat.com> References: <20191014153931.20699-1-mreitz@redhat.com> MIME-Version: 1.0 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 [10.5.110.31]); Mon, 14 Oct 2019 15:39:45 +0000 (UTC) Content-Transfer-Encoding: quoted-printable X-detected-operating-system: by eggs.gnu.org: GNU/Linux 2.2.x-3.x [generic] [fuzzy] X-Received-From: 209.132.183.28 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 , Vladimir Sementsov-Ogievskiy , John Snow , qemu-devel@nongnu.org, 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