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Bluetooth: __l2cap_wait_ack() add defensive timeout 

Add a timeout to prevent the do while loop running in an
infinite loop. This ensures that the channel will be
instructed to close within 10 seconds so prevents
l2cap_sock_shutdown() getting stuck forever.

Returns -ENOLINK when the timeout is reached. The channel
will be subequently closed and not all data will be ACK'ed.

Signed-off-by: Dean Jenkins <Dean_Jenkins@mentor.com>
Signed-off-by: Marcel Holtmann <marcel@holtmann.org>
This commit is contained in:
Dean Jenkins 2015-06-23 17:59:39 +01:00 committed by Marcel Holtmann
parent cb02a25583
commit e432c72c46
2 changed files with 11 additions and 1 deletions
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1
include/net/bluetooth/l2cap.h
View File

@ -56,6 +56,7 @@
#define L2CAP_MOVE_TIMEOUT msecs_to_jiffies(4000)
#define L2CAP_MOVE_ERTX_TIMEOUT msecs_to_jiffies(60000)
#define L2CAP_WAIT_ACK_POLL_PERIOD msecs_to_jiffies(200)
#define L2CAP_WAIT_ACK_TIMEOUT msecs_to_jiffies(10000)
#define L2CAP_A2MP_DEFAULT_MTU 670

11
net/bluetooth/l2cap_sock.c
View File

@ -1059,11 +1059,15 @@ static int __l2cap_wait_ack(struct sock *sk, struct l2cap_chan *chan)
DECLARE_WAITQUEUE(wait, current);
int err = 0;
int timeo = L2CAP_WAIT_ACK_POLL_PERIOD;
/* Timeout to prevent infinite loop */
unsigned long timeout = jiffies + L2CAP_WAIT_ACK_TIMEOUT;
add_wait_queue(sk_sleep(sk), &wait);
set_current_state(TASK_INTERRUPTIBLE);
do {
BT_DBG("Waiting for %d ACKs", chan->unacked_frames);
BT_DBG("Waiting for %d ACKs, timeout %04d ms",
chan->unacked_frames, time_after(jiffies, timeout) ? 0 :
jiffies_to_msecs(timeout - jiffies));
if (!timeo)
timeo = L2CAP_WAIT_ACK_POLL_PERIOD;
@ -1082,6 +1086,11 @@ static int __l2cap_wait_ack(struct sock *sk, struct l2cap_chan *chan)
if (err)
break;
if (time_after(jiffies, timeout)) {
err = -ENOLINK;
break;
}
} while (chan->unacked_frames > 0 &&
chan->state == BT_CONNECTED);