From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-9.8 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, INCLUDES_PATCH,MAILING_LIST_MULTI,SIGNED_OFF_BY,SPF_HELO_NONE,SPF_PASS, USER_AGENT_GIT autolearn=ham autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 0D70BC33CB1 for ; Thu, 16 Jan 2020 15:56:34 +0000 (UTC) Received: from lists.gnu.org (lists.gnu.org [209.51.188.17]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPS id D70C62077C for ; Thu, 16 Jan 2020 15:56:33 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org D70C62077C Authentication-Results: mail.kernel.org; dmarc=fail (p=none dis=none) header.from=virtuozzo.com Authentication-Results: mail.kernel.org; spf=pass smtp.mailfrom=qemu-devel-bounces+qemu-devel=archiver.kernel.org@nongnu.org Received: from localhost ([::1]:44214 helo=lists1p.gnu.org) by lists.gnu.org with esmtp (Exim 4.90_1) (envelope-from ) id 1is7VY-0007C1-TA for qemu-devel@archiver.kernel.org; Thu, 16 Jan 2020 10:56:32 -0500 Received: from eggs.gnu.org ([2001:470:142:3::10]:36846) by lists.gnu.org with esmtp (Exim 4.90_1) (envelope-from ) id 1is7UH-0005no-Ac for qemu-devel@nongnu.org; Thu, 16 Jan 2020 10:55:15 -0500 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1is7UF-0001bF-Rr for qemu-devel@nongnu.org; Thu, 16 Jan 2020 10:55:13 -0500 Received: from relay.sw.ru ([185.231.240.75]:58016) by eggs.gnu.org with esmtps (TLS1.0:DHE_RSA_AES_256_CBC_SHA1:32) (Exim 4.71) (envelope-from ) id 1is7UA-0001VK-Vf; Thu, 16 Jan 2020 10:55:07 -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 1is7Tz-00021t-W2; Thu, 16 Jan 2020 18:54:56 +0300 From: Vladimir Sementsov-Ogievskiy To: qemu-block@nongnu.org Subject: [PATCH 1/2] block/backup-top: fix failure path Date: Thu, 16 Jan 2020 18:54:51 +0300 Message-Id: <20200116155452.30972-2-vsementsov@virtuozzo.com> X-Mailer: git-send-email 2.21.0 In-Reply-To: <20200116155452.30972-1-vsementsov@virtuozzo.com> References: <20200116155452.30972-1-vsementsov@virtuozzo.com> MIME-Version: 1.0 Content-Transfer-Encoding: 8bit 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+qemu-devel=archiver.kernel.org@nongnu.org Sender: "Qemu-devel" 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 --- 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 818d3f26b4..19f18d541b 100644 --- a/block/backup-top.c +++ b/block/backup-top.c @@ -190,6 +190,7 @@ BlockDriverState *bdrv_backup_top_append(BlockDriverState *source, BlockDriverState *top = bdrv_new_open_driver(&bdrv_backup_top_filter, filter_node_name, BDRV_O_RDWR, errp); + bool appended = false; if (!top) { return NULL; @@ -212,8 +213,9 @@ BlockDriverState *bdrv_backup_top_append(BlockDriverState *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 = true; /* * bdrv_append() finished successfully, now we can require permissions @@ -224,14 +226,14 @@ BlockDriverState *bdrv_backup_top_append(BlockDriverState *source, if (local_err) { error_prepend(&local_err, "Cannot set permissions for backup-top filter: "); - goto failed_after_append; + goto fail; } state->bcs = block_copy_state_new(top->backing, state->target, cluster_size, write_flags, &local_err); if (local_err) { error_prepend(&local_err, "Cannot create block-copy-state: "); - goto failed_after_append; + goto fail; } *bcs = state->bcs; @@ -239,14 +241,15 @@ BlockDriverState *bdrv_backup_top_append(BlockDriverState *source, return top; -failed_after_append: - state->active = false; - bdrv_backup_top_drop(top); +fail: + if (appended) { + state->active = false; + bdrv_backup_top_drop(top); + } else { + bdrv_unref(top); + } -append_failed: bdrv_drained_end(source); - bdrv_unref_child(top, state->target); - bdrv_unref(top); error_propagate(errp, local_err); return NULL; -- 2.21.0