linux-kernel - [PATCH 4.9 68/77] bcache: Fix leak of bdev reference

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Date:   Sun, 24 Sep 2017 22:32:53 +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, Jan Kara <jack@...e.cz>,
        Coly Li <colyli@...e.de>, Jens Axboe <axboe@...nel.dk>
Subject: [PATCH 4.9 68/77] bcache: Fix leak of bdev reference

4.9-stable review patch.  If anyone has any objections, please let me know.

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

From: Jan Kara <jack@...e.cz>

commit 4b758df21ee7081ab41448d21d60367efaa625b3 upstream.

If blkdev_get_by_path() in register_bcache() fails, we try to lookup the
block device using lookup_bdev() to detect which situation we are in to
properly report error. However we never drop the reference returned to
us from lookup_bdev(). Fix that.

Signed-off-by: Jan Kara <jack@...e.cz>
Acked-by: Coly Li <colyli@...e.de>
Signed-off-by: Jens Axboe <axboe@...nel.dk>
Signed-off-by: Greg Kroah-Hartman <gregkh@...uxfoundation.org>

---
 drivers/md/bcache/super.c |    2 ++
 1 file changed, 2 insertions(+)

--- a/drivers/md/bcache/super.c
+++ b/drivers/md/bcache/super.c
@@ -1968,6 +1968,8 @@ static ssize_t register_bcache(struct ko
 			else
 				err = "device busy";
 			mutex_unlock(&bch_register_lock);
+			if (!IS_ERR(bdev))
+				bdput(bdev);
 			if (attr == &ksysfs_register_quiet)
 				goto out;
 		}