From c4f5627f7eeecde1bb6b646d8c0907b96dc2b2a6 Mon Sep 17 00:00:00 2001 From: Matthias Kaehlcke Date: Wed, 2 Jan 2019 16:11:20 -0800 Subject: Bluetooth: Fix locking in bt_accept_enqueue() for BH context With commit e16337622016 ("Bluetooth: Handle bt_accept_enqueue() socket atomically") lock_sock[_nested]() is used to acquire the socket lock before manipulating the socket. lock_sock[_nested]() may block, which is problematic since bt_accept_enqueue() can be called in bottom half context (e.g. from rfcomm_connect_ind()): [] __might_sleep+0x4c/0x80 [] lock_sock_nested+0x24/0x58 [] bt_accept_enqueue+0x48/0xd4 [bluetooth] [] rfcomm_connect_ind+0x190/0x218 [rfcomm] Add a parameter to bt_accept_enqueue() to indicate whether the function is called from BH context, and acquire the socket lock with bh_lock_sock_nested() if that's the case. Also adapt all callers of bt_accept_enqueue() to pass the new parameter: - l2cap_sock_new_connection_cb() - uses lock_sock() to lock the parent socket => process context - rfcomm_connect_ind() - acquires the parent socket lock with bh_lock_sock() => BH context - __sco_chan_add() - called from sco_chan_add(), which is called from sco_connect(). parent is NULL, hence bt_accept_enqueue() isn't called in this code path and we can ignore it - also called from sco_conn_ready(). uses bh_lock_sock() to acquire the parent lock => BH context Fixes: e16337622016 ("Bluetooth: Handle bt_accept_enqueue() socket atomically") Signed-off-by: Matthias Kaehlcke Reviewed-by: Douglas Anderson Signed-off-by: Marcel Holtmann Cc: stable@vger.kernel.org --- net/bluetooth/rfcomm/sock.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) (limited to 'net/bluetooth/rfcomm') diff --git a/net/bluetooth/rfcomm/sock.c b/net/bluetooth/rfcomm/sock.c index aa0db1d1bd9b..b1f49fcc0478 100644 --- a/net/bluetooth/rfcomm/sock.c +++ b/net/bluetooth/rfcomm/sock.c @@ -988,7 +988,7 @@ int rfcomm_connect_ind(struct rfcomm_session *s, u8 channel, struct rfcomm_dlc * rfcomm_pi(sk)->channel = channel; sk->sk_state = BT_CONFIG; - bt_accept_enqueue(parent, sk); + bt_accept_enqueue(parent, sk, true); /* Accept connection and return socket DLC */ *d = rfcomm_pi(sk)->dlc; -- cgit v1.2.3