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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>
This commit is contained in:
Dean Jenkins 2015-10-14 12:18:47 +02:00 committed by Marcel Holtmann
parent 04ba72e6b2
commit 9f7378a9d6
1 changed files with 10 additions and 1 deletions
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11
net/bluetooth/l2cap_sock.c
View File

@ -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);