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Commit f9adf422 authored by Jeffy Chen's avatar Jeffy Chen Committed by Greg Kroah-Hartman
Browse files

Bluetooth: cmtp: fix possible might sleep error in cmtp_session 

commit f06d977309d09253c744e54e75c5295ecc52b7b4 upstream.

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:
	dfb2fae7 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: default avatarJeffy Chen <jeffy.chen@rock-chips.com>
Reviewed-by: default avatarBrian Norris <briannorris@chromium.org>
Reviewed-by: default avatarAL Yu-Chen Cho <acho@suse.com>
Signed-off-by: default avatarMarcel Holtmann <marcel@holtmann.org>
Cc: Jiri Slaby <jslaby@suse.cz>
Signed-off-by: default avatarGreg Kroah-Hartman <gregkh@linuxfoundation.org>
parent 172bbb8e

net/bluetooth/cmtp/core.c

+10 −7
Original line number Diff line number Diff line
@@ -281,16 +281,16 @@ 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;
@@ -307,9 +307,8 @@ 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);
@@ -394,7 +393,7 @@ 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;

		}
@@ -432,7 +431,11 @@ 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;