[PATCH] Bluetooth: L2CAP: fix "bad unlock balance" in l2cap_disconnect_rsp

Min Li
2023-04-17T02:30:11Z

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>
---
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 55a7226233f9..24d075282996 100644
--- a/net/bluetooth/l2cap_core.c
+++ b/net/bluetooth/l2cap_core.c
@@ -4694,7 +4694,6 @@ 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;
}

--
2.25.1