From: Min Li <lm0963hack@gmail.com>
Date: Mon, 17 Apr 2023 02:27:54 +0000 (+0800)
Subject: Bluetooth: L2CAP: fix "bad unlock balance" in l2cap_disconnect_rsp
X-Git-Tag: baikal/aarch64/sdk5.10~123
X-Git-Url: https://git.baikalelectronics.ru/?a=commitdiff_plain;h=d298919e5d5b86749a4be49aa68f98dfac4006cd;p=kernel.git

Bluetooth: L2CAP: fix "bad unlock balance" in l2cap_disconnect_rsp

[ 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>
---

diff --git a/net/bluetooth/l2cap_core.c b/net/bluetooth/l2cap_core.c
index 3c559a177761b..5f53e75d83024 100644
--- a/net/bluetooth/l2cap_core.c
+++ b/net/bluetooth/l2cap_core.c
@@ -4410,7 +4410,6 @@ 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;
 	}