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

Greg Kroah-Hartman
2020-09-08T18:06:53Z

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
@@ -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;
}