linux-kernel - [PATCH 4.9 001/241] blkcg: fix double free of new_blkg in blkcg_init

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Date:   Mon, 19 Mar 2018 19:04:26 +0100
From:   Greg Kroah-Hartman <gregkh@...uxfoundation.org>
To:     linux-kernel@...r.kernel.org
Cc:     Greg Kroah-Hartman <gregkh@...uxfoundation.org>,
        stable@...r.kernel.org, Hou Tao <houtao1@...wei.com>,
        Jens Axboe <axboe@...com>, Guenter Roeck <linux@...ck-us.net>
Subject: [PATCH 4.9 001/241] blkcg: fix double free of new_blkg in blkcg_init_queue

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

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

From: Hou Tao <houtao1@...wei.com>

commit 9b54d816e00425c3a517514e0d677bb3cec49258 upstream.

If blkg_create fails, new_blkg passed as an argument will
be freed by blkg_create, so there is no need to free it again.

Signed-off-by: Hou Tao <houtao1@...wei.com>
Signed-off-by: Jens Axboe <axboe@...com>
Cc: Guenter Roeck <linux@...ck-us.net>
Signed-off-by: Greg Kroah-Hartman <gregkh@...uxfoundation.org>

---
 block/blk-cgroup.c |    4 +---
 1 file changed, 1 insertion(+), 3 deletions(-)

--- a/block/blk-cgroup.c
+++ b/block/blk-cgroup.c
@@ -1078,10 +1078,8 @@ int blkcg_init_queue(struct request_queu
 	if (preloaded)
 		radix_tree_preload_end();
 
-	if (IS_ERR(blkg)) {
-		blkg_free(new_blkg);
+	if (IS_ERR(blkg))
 		return PTR_ERR(blkg);
-	}
 
 	q->root_blkg = blkg;
 	q->root_rl.blkg = blkg;