Bluetooth: RFCOMM: FIX possible deadlock in rfcomm_sk_state_change

[ Upstream commit 08d1914 ]

rfcomm_sk_state_change attempts to use sock_lock so it must never be
called with it locked but rfcomm_sock_ioctl always attempt to lock it
causing the following trace:

======================================================
WARNING: possible circular locking dependency detected
6.8.0-syzkaller-08951-gfe46a7dd189e #0 Not tainted
------------------------------------------------------
syz-executor386/5093 is trying to acquire lock:
ffff88807c396258 (sk_lock-AF_BLUETOOTH-BTPROTO_RFCOMM){+.+.}-{0:0}, at: lock_sock include/net/sock.h:1671 [inline]
ffff88807c396258 (sk_lock-AF_BLUETOOTH-BTPROTO_RFCOMM){+.+.}-{0:0}, at: rfcomm_sk_state_change+0x5b/0x310 net/bluetooth/rfcomm/sock.c:73

but task is already holding lock:
ffff88807badfd28 (&d->lock){+.+.}-{3:3}, at: __rfcomm_dlc_close+0x226/0x6a0 net/bluetooth/rfcomm/core.c:491

Reported-by: [email protected]
Tested-by: [email protected]
Closes: https://syzkaller.appspot.com/bug?extid=d7ce59b06b3eb14fd218
Fixes: 3241ad8 ("[Bluetooth] Add timestamp support to L2CAP, RFCOMM and SCO")
Signed-off-by: Luiz Augusto von Dentz <[email protected]>
Signed-off-by: Sasha Levin <[email protected]>

Author: Vudentz

net/bluetooth/rfcomm/sock.c

@@ -865,9 +865,7 @@ static int rfcomm_sock_ioctl(struct socket *sock, unsigned int cmd, unsigned lon
 
 	if (err == -ENOIOCTLCMD) {
 #ifdef CONFIG_BT_RFCOMM_TTY
-		lock_sock(sk);
 		err = rfcomm_dev_ioctl(sk, cmd, (void __user *) arg);
-		release_sock(sk);
 #else
 		err = -EOPNOTSUPP;
 #endif