can: isotp: handle wait_event_interruptible() return values

When wait_event_interruptible() has been interrupted by a signal the
tx.state value might not be ISOTP_IDLE. Force the state machines
into idle state to inhibit the timer handlers to continue working.

Fixes: 86633786 ("can: isotp: fix tx state handling for echo tx processing")
Cc: stable@vger.kernel.org
Signed-off-by: Oliver Hartkopp <socketcan@hartkopp.net>
Link: https://lore.kernel.org/all/20230112192347.1944-1-socketcan@hartkopp.netSigned-off-by: Marc Kleine-Budde <mkl@pengutronix.de>

net/can/isotp.c

@@ -1162,6 +1162,10 @@ static int isotp_release(struct socket *sock)
 	/* wait for complete transmission of current pdu */
 	wait_event_interruptible(so->wait, so->tx.state == ISOTP_IDLE);
 
+	/* force state machines to be idle also when a signal occurred */
+	so->tx.state = ISOTP_IDLE;
+	so->rx.state = ISOTP_IDLE;
+
 	spin_lock(&isotp_notifier_lock);
 	while (isotp_busy_notifier == so) {
 		spin_unlock(&isotp_notifier_lock);