[PATCH 3.8-stable] mnt: release locks on error path in do_loopback

[Jonghwan Choi]

From: Andrey Vagin <avagin@xxxxxxxxxx>

This patch looks like it should be in the 3.8-stable tree, should we apply
it?

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

From: "Andrey Vagin <avagin@xxxxxxxxxx>"

commit e9c5d8a562f01b211926d70443378eb14b29a676 upstream

do_loopback calls lock_mount(path) and forget to unlock_mount
if clone_mnt or copy_mnt fails.

[   77.661566] ================================================
[   77.662939] [ BUG: lock held when returning to user space! ]
[   77.664104] 3.9.0-rc5+ #17 Not tainted
[   77.664982] ------------------------------------------------
[   77.666488] mount/514 is leaving the kernel with locks still held!
[   77.668027] 2 locks held by mount/514:
[   77.668817]  #0:  (&sb->s_type->i_mutex_key#7){+.+.+.}, at: [<ffffffff811cca22>] lock_mount+0x32/0xe0
[   77.671755]  #1:  (&namespace_sem){+++++.}, at: [<ffffffff811cca3a>] lock_mount+0x4a/0xe0

Signed-off-by: Andrey Vagin <avagin@xxxxxxxxxx>
Signed-off-by: Al Viro <viro@xxxxxxxxxxxxxxxxxx>
Signed-off-by: Jonghwan Choi <jhbird.choi@xxxxxxxxxxx>
---
 fs/namespace.c |    2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/fs/namespace.c b/fs/namespace.c
index 5dd7709..4abc8c0 100644
--- a/fs/namespace.c
+++ b/fs/namespace.c
@@ -1713,7 +1713,7 @@ static int do_loopback(struct path *path, const char *old_name,
 
 	if (IS_ERR(mnt)) {
 		err = PTR_ERR(mnt);
-		goto out;
+		goto out2;
 	}
 
 	err = graft_tree(mnt, path);
-- 
1.7.10.4

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