linux-kernel - [PATCH 4.19 77/88] dm cache metadata: Avoid returning cmd->bm wild pointer on error

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Message-Id: <20200908152225.034843176@linuxfoundation.org>
Date:   Tue,  8 Sep 2020 17:26:18 +0200
From:   Greg Kroah-Hartman <gregkh@...uxfoundation.org>
To:     linux-kernel@...r.kernel.org
Cc:     Greg Kroah-Hartman <gregkh@...uxfoundation.org>,
        stable@...r.kernel.org, Ye Bin <yebin10@...wei.com>,
        Mike Snitzer <snitzer@...hat.com>
Subject: [PATCH 4.19 77/88] dm cache metadata: Avoid returning cmd->bm wild pointer on error

From: Ye Bin <yebin10@...wei.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@...wei.com>
Cc: stable@...r.kernel.org
Signed-off-by: Mike Snitzer <snitzer@...hat.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@...uxfoundation.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
@@ -537,12 +537,16 @@ 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;
 }