[PATCH 4.19 78/88] dm thin metadata: Avoid returning cmd->bm wild pointer on error

[Greg Kroah-Hartman]

From: Ye Bin <yebin10@xxxxxxxxxx>

commit 219403d7e56f9b716ad80ab87db85d29547ee73e 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@xxxxxxxxxx>
Cc: stable@xxxxxxxxxxxxxxx
Signed-off-by: Mike Snitzer <snitzer@xxxxxxxxxx>
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>

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

--- a/drivers/md/dm-thin-metadata.c
+++ b/drivers/md/dm-thin-metadata.c
@@ -698,12 +698,16 @@ static int __create_persistent_data_obje
 					  THIN_MAX_CONCURRENT_LOCKS);
 	if (IS_ERR(pmd->bm)) {
 		DMERR("could not create block manager");
-		return PTR_ERR(pmd->bm);
+		r = PTR_ERR(pmd->bm);
+		pmd->bm = NULL;
+		return r;
 	}
 
 	r = __open_or_format_metadata(pmd, format_device);
-	if (r)
+	if (r) {
 		dm_block_manager_destroy(pmd->bm);
+		pmd->bm = NULL;
+	}
 
 	return r;
 }