linux-kernel - [PATCH AUTOSEL 5.4 18/18] Bluetooth: L2CAP: fix "bad unlock balance" in l2cap_disconnect

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Message-Id: <20230504195042.3808716-18-sashal@kernel.org>
Date:   Thu,  4 May 2023 15:50:40 -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 5.4 18/18] 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 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;
 	}
 
-- 
2.39.2