[PATCH AUTOSEL 5.10 24/24] Bluetooth: L2CAP: fix "bad unlock balance" in l2cap_disconnect_rsp

Sasha Levin
2023-05-04T20:14:29Z

From: Min Li <lm0963hack@gmail.com>

[ Upstream commit 25e97f7b1866e6b8503be349eeea44bb52d661ce ]

conn->chan_lock isn't acquired before l2cap_get_chan_by_scid,
if l2cap_get_chan_by_scid returns NULL, then 'bad unlock balance'
is triggered.

Reported-by: syzbot+9519d6b5b79cf7787cf3@syzkaller.appspotmail.com
Link: https://lore.kernel.org/all/000000000000894f5f05f95e9f4d@google.com/
Signed-off-by: Min Li <lm0963hack@gmail.com>
Signed-off-by: Luiz Augusto von Dentz <luiz.von.dentz@intel.com>
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
net/bluetooth/l2cap_core.c | 1 -
1 file changed, 1 deletion(-)

diff --git a/net/bluetooth/l2cap_core.c b/net/bluetooth/l2cap_core.c
index f9d2ce9cee369..b85ce276e2a3c 100644
--- a/net/bluetooth/l2cap_core.c
+++ b/net/bluetooth/l2cap_core.c
@@ -4689,7 +4689,6 @@ static inline int l2cap_disconnect_rsp(struct l2cap_conn *conn,

chan = l2cap_get_chan_by_scid(conn, scid);
if (!chan) {
- mutex_unlock(&conn->chan_lock);
return 0;
}

--
2.39.2