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From:   Ben Hutchings <ben@decadent.org.uk>
To:     linux-kernel@vger.kernel.org, stable@vger.kernel.org
CC:     akpm@linux-foundation.org, "Shenghui Wang" <shhuiw@foxmail.com>,
        "Mike Snitzer" <snitzer@redhat.com>
Date:   Sun, 09 Dec 2018 21:50:33 +0000
Message-ID: <lsq.1544392233.199570981@decadent.org.uk>
Subject: [PATCH 3.16 306/328] dm cache: destroy migration_cache if cache
 target registration failed
In-Reply-To: <lsq.1544392232.713909046@decadent.org.uk>
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3.16.62-rc1 review patch.  If anyone has any objections, please let me know.

------------------

From: Shenghui Wang <shhuiw@foxmail.com>

commit c7cd55504a5b0fc826a2cd9540845979d24ae542 upstream.

Commit 7e6358d244e47 ("dm: fix various targets to dm_register_target
after module __init resources created") inadvertently introduced this
bug when it moved dm_register_target() after the call to KMEM_CACHE().

Fixes: 7e6358d244e47 ("dm: fix various targets to dm_register_target after module __init resources created")
Signed-off-by: Shenghui Wang <shhuiw@foxmail.com>
Signed-off-by: Mike Snitzer <snitzer@redhat.com>
Signed-off-by: Ben Hutchings <ben@decadent.org.uk>
---
 drivers/md/dm-cache-target.c | 5 ++---
 1 file changed, 2 insertions(+), 3 deletions(-)

--- a/drivers/md/dm-cache-target.c
+++ b/drivers/md/dm-cache-target.c
@@ -3109,14 +3109,13 @@ static int __init dm_cache_init(void)
 	int r;
 
 	migration_cache = KMEM_CACHE(dm_cache_migration, 0);
-	if (!migration_cache) {
-		dm_unregister_target(&cache_target);
+	if (!migration_cache)
 		return -ENOMEM;
-	}
 
 	r = dm_register_target(&cache_target);
 	if (r) {
 		DMERR("cache target registration failed: %d", r);
+		kmem_cache_destroy(migration_cache);
 		return r;
 	}