[PATCH 5.2 285/413] bcache: destroy dc->writeback_write_wq if failed to create dc->writeback_thread

[Greg Kroah-Hartman]

From: Coly Li <colyli@xxxxxxx>

commit f54d801dda14942dbefa00541d10603015b7859c upstream.

Commit 9baf30972b55 ("bcache: fix for gc and write-back race") added a
new work queue dc->writeback_write_wq, but forgot to destroy it in the
error condition when creating dc->writeback_thread failed.

This patch destroys dc->writeback_write_wq if kthread_create() returns
error pointer to dc->writeback_thread, then a memory leak is avoided.

Fixes: 9baf30972b55 ("bcache: fix for gc and write-back race")
Signed-off-by: Coly Li <colyli@xxxxxxx>
Cc: stable@xxxxxxxxxxxxxxx
Signed-off-by: Jens Axboe <axboe@xxxxxxxxx>
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>

---
 drivers/md/bcache/writeback.c |    1 +
 1 file changed, 1 insertion(+)

--- a/drivers/md/bcache/writeback.c
+++ b/drivers/md/bcache/writeback.c
@@ -834,6 +834,7 @@ int bch_cached_dev_writeback_start(struc
 					      "bcache_writeback");
 	if (IS_ERR(dc->writeback_thread)) {
 		cached_dev_put(dc);
+		destroy_workqueue(dc->writeback_write_wq);
 		return PTR_ERR(dc->writeback_thread);
 	}
 	dc->writeback_running = true;