netdev - [PATCH AUTOSEL 4.19 13/13] Bluetooth: L2CAP: fix "bad unlock balance" in l2cap_disconnect

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Date: Thu,  4 May 2023 15:51:30 -0400
From: Sasha Levin <sashal@...nel.org>
To: linux-kernel@...r.kernel.org,
	stable@...r.kernel.org
Cc: Min Li <lm0963hack@...il.com>,
	syzbot+9519d6b5b79cf7787cf3@...kaller.appspotmail.com,
	Luiz Augusto von Dentz <luiz.von.dentz@...el.com>,
	Sasha Levin <sashal@...nel.org>,
	marcel@...tmann.org,
	johan.hedberg@...il.com,
	luiz.dentz@...il.com,
	davem@...emloft.net,
	edumazet@...gle.com,
	kuba@...nel.org,
	pabeni@...hat.com,
	linux-bluetooth@...r.kernel.org,
	netdev@...r.kernel.org
Subject: [PATCH AUTOSEL 4.19 13/13] Bluetooth: L2CAP: fix "bad unlock balance" in l2cap_disconnect_rsp

From: Min Li <lm0963hack@...il.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@...kaller.appspotmail.com
Link: https://lore.kernel.org/all/000000000000894f5f05f95e9f4d@google.com/
Signed-off-by: Min Li <lm0963hack@...il.com>
Signed-off-by: Luiz Augusto von Dentz <luiz.von.dentz@...el.com>
Signed-off-by: Sasha Levin <sashal@...nel.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 1a68aad5737e1..94d40a20ab958 100644
--- a/net/bluetooth/l2cap_core.c
+++ b/net/bluetooth/l2cap_core.c
@@ -4392,7 +4392,6 @@ 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