Commit 9f7378a9 authored Oct 14, 2015 by Dean Jenkins Committed by Marcel Holtmann Oct 21, 2015

Bluetooth: l2cap_disconnection_req priority over shutdown



There is a L2CAP protocol race between the local peer and
the remote peer demanding disconnection of the L2CAP link.

When L2CAP ERTM is used, l2cap_sock_shutdown() can be called
from userland to disconnect L2CAP. However, there can be a
delay introduced by waiting for ACKs. During this waiting
period, the remote peer may have sent a Disconnection Request.
Therefore, recheck the shutdown status of the socket
after waiting for ACKs because there is no need to do
further processing if the connection has gone.

Signed-off-by: Dean Jenkins <Dean_Jenkins@mentor.com>
Signed-off-by: Harish Jenny K N <harish_kandiga@mentor.com>
Signed-off-by: Marcel Holtmann <marcel@holtmann.org>

parent 04ba72e6

net/bluetooth/l2cap_sock.c

+10 −1

Original line number	Diff line number	Diff line
		@@ -1129,9 +1129,17 @@ static int l2cap_sock_shutdown(struct socket *sock, int how)

		if (chan->mode == L2CAP_MODE_ERTM &&
		chan->unacked_frames > 0 &&
		chan->state == BT_CONNECTED)
		chan->state == BT_CONNECTED) {
		err = __l2cap_wait_ack(sk, chan);

		/* After waiting for ACKs, check whether shutdown
		* has already been actioned to close the L2CAP
		* link such as by l2cap_disconnection_req().
		*/
		if (sk->sk_shutdown)
		goto has_shutdown;
		}

		sk->sk_shutdown = SHUTDOWN_MASK;
		release_sock(sk);

		@@ -1162,6 +1170,7 @@ static int l2cap_sock_shutdown(struct socket *sock, int how)
		err = bt_sock_wait_state(sk, BT_CLOSED,
		sk->sk_lingertime);

		has_shutdown:
		l2cap_chan_put(chan);
		sock_put(sk);

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