Bluetooth: bnep: fix possible might sleep error in bnep_session

commit 25717382c1dd0ddced2059053e3ca5088665f7a5 upstream.

It looks like bnep_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>
Cc: Jiri Slaby <jslaby@suse.cz>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

diff --git a/net/bluetooth/bnep/core.c b/net/bluetooth/bnep/core.c
index 1641367..69f5607 100644 (file)
--- a/net/bluetooth/bnep/core.c
+++ b/net/bluetooth/bnep/core.c
@@ -484,16 +484,16 @@ static int bnep_session(void *arg)
        struct net_device *dev = s->dev;
        struct sock *sk = s->sock->sk;
        struct sk_buff *skb;
-       wait_queue_t wait;
+       DEFINE_WAIT_FUNC(wait, woken_wake_function);
 
        BT_DBG("");
 
        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(&s->terminate))
                        break;
@@ -515,9 +515,8 @@ static int bnep_session(void *arg)
                                break;
                netif_wake_queue(dev);
 
-               schedule();
+               wait_woken(&wait, TASK_INTERRUPTIBLE, MAX_SCHEDULE_TIMEOUT);
        }
-       __set_current_state(TASK_RUNNING);
        remove_wait_queue(sk_sleep(sk), &wait);
 
        /* Cleanup session */
@@ -663,7 +662,7 @@ int bnep_del_connection(struct bnep_conndel_req *req)
        s = __bnep_get_session(req->dst);
        if (s) {
                atomic_inc(&s->terminate);
-               wake_up_process(s->task);
+               wake_up_interruptible(sk_sleep(s->sock->sk));
        } else
                err = -ENOENT;