From nobody Mon Feb 9 02:28:18 2026 Delivered-To: importer@patchew.org Received-SPF: pass (zohomail.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 (zohomail.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=virtuozzo.com ARC-Seal: i=1; a=rsa-sha256; t=1579617015; cv=none; d=zohomail.com; s=zohoarc; b=hPNv5OoKGfxRBTEo6Cx8ULKu9x+vhDvBUguDVptkjhTb2MPkR77Jm9NEI6obCnvFyfLUjC1BzBhmqAHi0YA9QfvutQq79FWFJDg5rKqy+CBVeNcKVBs1UTtZnFfcuQX0yggxmJ4895d5fD53MKN4JjifMmUj8pJFRKMh3aAHAUw= ARC-Message-Signature: i=1; a=rsa-sha256; c=relaxed/relaxed; d=zohomail.com; s=zohoarc; t=1579617015; 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=Z3fgKtGtg89p/B0Ny32RKFu0IceQeWR5eA6YG/YB40s=; b=kS6bOktelm5jSrPKPcDP7tKIV2Za3dScPvuQRLDsGbDtG9kSuudg7eJCaDhVkaole26KGtkjJ7De7B383REXgGDF+J2U9Y3Wr8jYflVkyaqxt/wEyBUwoA8fOQSFaDLJOtL0gc7/p7uoFM7s0jM7qr2iQEgUy4Vd72Ii5RGkm9Y= ARC-Authentication-Results: i=1; mx.zohomail.com; spf=pass (zohomail.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 1579617015328435.42479397698924; Tue, 21 Jan 2020 06:30:15 -0800 (PST) Received: from localhost ([::1]:55278 helo=lists1p.gnu.org) by lists.gnu.org with esmtp (Exim 4.90_1) (envelope-from ) id 1ituXl-0003NP-HY for importer@patchew.org; Tue, 21 Jan 2020 09:30:13 -0500 Received: from eggs.gnu.org ([2001:470:142:3::10]:44715) by lists.gnu.org with esmtp (Exim 4.90_1) (envelope-from ) id 1ituVz-0001WH-At for qemu-devel@nongnu.org; Tue, 21 Jan 2020 09:28:24 -0500 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1ituVx-0000hn-FJ for qemu-devel@nongnu.org; Tue, 21 Jan 2020 09:28:23 -0500 Received: from relay.sw.ru ([185.231.240.75]:50840) by eggs.gnu.org with esmtps (TLS1.0:DHE_RSA_AES_256_CBC_SHA1:32) (Exim 4.71) (envelope-from ) id 1ituVt-0000dk-5t; Tue, 21 Jan 2020 09:28:17 -0500 Received: from vovaso.qa.sw.ru ([10.94.3.0] helo=kvm.qa.sw.ru) by relay.sw.ru with esmtp (Exim 4.92.3) (envelope-from ) id 1ituVo-0000mn-Ji; Tue, 21 Jan 2020 17:28:12 +0300 From: Vladimir Sementsov-Ogievskiy To: qemu-block@nongnu.org Subject: [PATCH v2 1/2] block/backup-top: fix failure path Date: Tue, 21 Jan 2020 17:28:01 +0300 Message-Id: <20200121142802.21467-2-vsementsov@virtuozzo.com> X-Mailer: git-send-email 2.21.0 In-Reply-To: <20200121142802.21467-1-vsementsov@virtuozzo.com> References: <20200121142802.21467-1-vsementsov@virtuozzo.com> MIME-Version: 1.0 Content-Transfer-Encoding: quoted-printable X-detected-operating-system: by eggs.gnu.org: GNU/Linux 3.x [fuzzy] X-Received-From: 185.231.240.75 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: kwolf@redhat.com, qemu-stable@nongnu.org, vsementsov@virtuozzo.com, qemu-devel@nongnu.org, mreitz@redhat.com Errors-To: qemu-devel-bounces+importer=patchew.org@nongnu.org Sender: "Qemu-devel" Content-Type: text/plain; charset="utf-8" We can't access top after call bdrv_backup_top_drop, as it is already freed at this time. Also, no needs to unref target child by hand, it will be unrefed on bdrv_close() automatically. So, just do bdrv_backup_top_drop if append succeed and one bdrv_unref otherwise. Note, that in !appended case bdrv_unref(top) moved into drained section on source. It doesn't really matter, but just for code simplicity. Fixes: 7df7868b96404 Cc: qemu-stable@nongnu.org # v4.2.0 Signed-off-by: Vladimir Sementsov-Ogievskiy Reviewed-by: Max Reitz --- block/backup-top.c | 21 ++++++++++++--------- 1 file changed, 12 insertions(+), 9 deletions(-) diff --git a/block/backup-top.c b/block/backup-top.c index b8d863ff08..cdfec782e2 100644 --- a/block/backup-top.c +++ b/block/backup-top.c @@ -190,6 +190,7 @@ BlockDriverState *bdrv_backup_top_append(BlockDriverSta= te *source, BlockDriverState *top =3D bdrv_new_open_driver(&bdrv_backup_top_filter, filter_node_name, BDRV_O_RDWR, errp); + bool appended =3D false; =20 if (!top) { return NULL; @@ -212,8 +213,9 @@ BlockDriverState *bdrv_backup_top_append(BlockDriverSta= te *source, bdrv_append(top, source, &local_err); if (local_err) { error_prepend(&local_err, "Cannot append backup-top filter: "); - goto append_failed; + goto fail; } + appended =3D true; =20 /* * bdrv_append() finished successfully, now we can require permissions @@ -224,14 +226,14 @@ BlockDriverState *bdrv_backup_top_append(BlockDriverS= tate *source, if (local_err) { error_prepend(&local_err, "Cannot set permissions for backup-top filter: "); - goto failed_after_append; + goto fail; } =20 state->bcs =3D block_copy_state_new(top->backing, state->target, cluster_size, write_flags, &local_er= r); if (local_err) { error_prepend(&local_err, "Cannot create block-copy-state: "); - goto failed_after_append; + goto fail; } *bcs =3D state->bcs; =20 @@ -239,14 +241,15 @@ BlockDriverState *bdrv_backup_top_append(BlockDriverS= tate *source, =20 return top; =20 -failed_after_append: - state->active =3D false; - bdrv_backup_top_drop(top); +fail: + if (appended) { + state->active =3D false; + bdrv_backup_top_drop(top); + } else { + bdrv_unref(top); + } =20 -append_failed: bdrv_drained_end(source); - bdrv_unref_child(top, state->target); - bdrv_unref(top); error_propagate(errp, local_err); =20 return NULL; --=20 2.21.0