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Bluetooth: cmtp: fix possible might sleep error in cmtp_session

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It looks like cmtp_session has same pattern as the issue reported in
old rfcomm:

	while (1) {
		set_current_state(TASK_INTERRUPTIBLE);
		if (condition)
			break;
		// may call might_sleep here
		schedule();
	}
	__set_current_state(TASK_RUNNING);

Which fixed at:
	dfb2fae Bluetooth: Fix nested sleeps

So let's fix it at the same way, also follow the suggestion of:
https://lwn.net/Articles/628628/

Signed-off-by: Jeffy Chen <jeffy.chen@rock-chips.com>
Reviewed-by: Brian Norris <briannorris@chromium.org>
Reviewed-by: AL Yu-Chen Cho <acho@suse.com>
Signed-off-by: Marcel Holtmann <marcel@holtmann.org>
This commit is contained in:
Jeffy Chen 2017-06-27 17:34:43 +08:00 committed by Marcel Holtmann
parent 25717382c1
commit f06d977309
1 changed files with 10 additions and 7 deletions
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17
net/bluetooth/cmtp/core.c
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@ -280,16 +280,16 @@ static int cmtp_session(void *arg)
struct cmtp_session *session = arg;
struct sock *sk = session->sock->sk;
struct sk_buff *skb;
wait_queue_t wait;
DEFINE_WAIT_FUNC(wait, woken_wake_function);
BT_DBG("session %p", session);
set_user_nice(current, -15);
init_waitqueue_entry(&wait, current);
add_wait_queue(sk_sleep(sk), &wait);
while (1) {
set_current_state(TASK_INTERRUPTIBLE);
/* Ensure session->terminate is updated */
smp_mb__before_atomic();
if (atomic_read(&session->terminate))
break;
@ -306,9 +306,8 @@ static int cmtp_session(void *arg)
cmtp_process_transmit(session);
schedule();
wait_woken(&wait, TASK_INTERRUPTIBLE, MAX_SCHEDULE_TIMEOUT);
}
__set_current_state(TASK_RUNNING);
remove_wait_queue(sk_sleep(sk), &wait);
down_write(&cmtp_session_sem);
@ -393,7 +392,7 @@ int cmtp_add_connection(struct cmtp_connadd_req *req, struct socket *sock)
err = cmtp_attach_device(session);
if (err < 0) {
atomic_inc(&session->terminate);
wake_up_process(session->task);
wake_up_interruptible(sk_sleep(session->sock->sk));
up_write(&cmtp_session_sem);
return err;
}
@ -431,7 +430,11 @@ int cmtp_del_connection(struct cmtp_conndel_req *req)
/* Stop session thread */
atomic_inc(&session->terminate);
wake_up_process(session->task);
/* Ensure session->terminate is updated */
smp_mb__after_atomic();
wake_up_interruptible(sk_sleep(session->sock->sk));
} else
err = -ENOENT;