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From:   Greg Kroah-Hartman <gregkh@linuxfoundation.org>
To:     linux-kernel@vger.kernel.org
Cc:     Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
        stable@vger.kernel.org, Ye Bin <yebin10@huawei.com>,
        Mike Snitzer <snitzer@redhat.com>
Subject: [PATCH 4.9 46/71] dm cache metadata: Avoid returning cmd->bm wild pointer on error
Date:   Fri, 11 Sep 2020 14:46:30 +0200
Message-Id: <20200911122507.216504913@linuxfoundation.org>
In-Reply-To: <20200911122504.928931589@linuxfoundation.org>
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From: Ye Bin <yebin10@huawei.com>

commit d16ff19e69ab57e08bf908faaacbceaf660249de upstream.

Maybe __create_persistent_data_objects() caller will use PTR_ERR as a
pointer, it will lead to some strange things.

Signed-off-by: Ye Bin <yebin10@huawei.com>
Cc: stable@vger.kernel.org
Signed-off-by: Mike Snitzer <snitzer@redhat.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

---
 drivers/md/dm-cache-metadata.c |    8 ++++++--
 1 file changed, 6 insertions(+), 2 deletions(-)

--- a/drivers/md/dm-cache-metadata.c
+++ b/drivers/md/dm-cache-metadata.c
@@ -508,12 +508,16 @@ static int __create_persistent_data_obje
 					  CACHE_MAX_CONCURRENT_LOCKS);
 	if (IS_ERR(cmd->bm)) {
 		DMERR("could not create block manager");
-		return PTR_ERR(cmd->bm);
+		r = PTR_ERR(cmd->bm);
+		cmd->bm = NULL;
+		return r;
 	}
 
 	r = __open_or_format_metadata(cmd, may_format_device);
-	if (r)
+	if (r) {
 		dm_block_manager_destroy(cmd->bm);
+		cmd->bm = NULL;
+	}
 
 	return r;
 }