Commit 241f5193 authored by Luiz Augusto von Dentz's avatar Luiz Augusto von Dentz
Browse files

Bluetooth: ISO: Avoid circular locking dependency 



This attempts to avoid circular locking dependency between sock_lock
and hdev_lock:

WARNING: possible circular locking dependency detected
6.0.0-rc7-03728-g18dd8ab0a783 #3 Not tainted
------------------------------------------------------
kworker/u3:2/53 is trying to acquire lock:
ffff888000254130 (sk_lock-AF_BLUETOOTH-BTPROTO_ISO){+.+.}-{0:0}, at:
iso_conn_del+0xbd/0x1d0
but task is already holding lock:
ffffffff9f39a080 (hci_cb_list_lock){+.+.}-{3:3}, at:
hci_le_cis_estabilished_evt+0x1b5/0x500
which lock already depends on the new lock.
the existing dependency chain (in reverse order) is:
-> #2 (hci_cb_list_lock){+.+.}-{3:3}:
       __mutex_lock+0x10e/0xfe0
       hci_le_remote_feat_complete_evt+0x17f/0x320
       hci_event_packet+0x39c/0x7d0
       hci_rx_work+0x2bf/0x950
       process_one_work+0x569/0x980
       worker_thread+0x2a3/0x6f0
       kthread+0x153/0x180
       ret_from_fork+0x22/0x30
-> #1 (&hdev->lock){+.+.}-{3:3}:
       __mutex_lock+0x10e/0xfe0
       iso_connect_cis+0x6f/0x5a0
       iso_sock_connect+0x1af/0x710
       __sys_connect+0x17e/0x1b0
       __x64_sys_connect+0x37/0x50
       do_syscall_64+0x43/0x90
       entry_SYSCALL_64_after_hwframe+0x62/0xcc
-> #0 (sk_lock-AF_BLUETOOTH-BTPROTO_ISO){+.+.}-{0:0}:
       __lock_acquire+0x1b51/0x33d0
       lock_acquire+0x16f/0x3b0
       lock_sock_nested+0x32/0x80
       iso_conn_del+0xbd/0x1d0
       iso_connect_cfm+0x226/0x680
       hci_le_cis_estabilished_evt+0x1ed/0x500
       hci_event_packet+0x39c/0x7d0
       hci_rx_work+0x2bf/0x950
       process_one_work+0x569/0x980
       worker_thread+0x2a3/0x6f0
       kthread+0x153/0x180
       ret_from_fork+0x22/0x30
other info that might help us debug this:
Chain exists of:
  sk_lock-AF_BLUETOOTH-BTPROTO_ISO --> &hdev->lock --> hci_cb_list_lock
 Possible unsafe locking scenario:
       CPU0                    CPU1
       ----                    ----
  lock(hci_cb_list_lock);
                               lock(&hdev->lock);
                               lock(hci_cb_list_lock);
  lock(sk_lock-AF_BLUETOOTH-BTPROTO_ISO);
 *** DEADLOCK ***
4 locks held by kworker/u3:2/53:
 #0: ffff8880021d9130 ((wq_completion)hci0#2){+.+.}-{0:0}, at:
 process_one_work+0x4ad/0x980
 #1: ffff888002387de0 ((work_completion)(&hdev->rx_work)){+.+.}-{0:0},
 at: process_one_work+0x4ad/0x980
 #2: ffff888001ac0070 (&hdev->lock){+.+.}-{3:3}, at:
 hci_le_cis_estabilished_evt+0xc3/0x500
 #3: ffffffff9f39a080 (hci_cb_list_lock){+.+.}-{3:3}, at:
 hci_le_cis_estabilished_evt+0x1b5/0x500

Signed-off-by: default avatarLuiz Augusto von Dentz <luiz.von.dentz@intel.com>
parent 0ba18967

net/bluetooth/iso.c

+38 −23
Original line number Diff line number Diff line
@@ -261,13 +261,13 @@ static int iso_connect_bis(struct sock *sk) 


	if (!bis_capable(hdev)) {

		err = -EOPNOTSUPP;

		goto done;

		goto unlock;

	}



	/* Fail if out PHYs are marked as disabled */

	if (!iso_pi(sk)->qos.out.phy) {

		err = -EINVAL;

		goto done;

		goto unlock;

	}



	hcon = hci_connect_bis(hdev, &iso_pi(sk)->dst,
@@ -276,22 +276,27 @@ static int iso_connect_bis(struct sock *sk) 
			       iso_pi(sk)->base);

	if (IS_ERR(hcon)) {

		err = PTR_ERR(hcon);

		goto done;

		goto unlock;

	}



	conn = iso_conn_add(hcon);

	if (!conn) {

		hci_conn_drop(hcon);

		err = -ENOMEM;

		goto done;

		goto unlock;

	}



	hci_dev_unlock(hdev);

	hci_dev_put(hdev);



	lock_sock(sk);



	/* Update source addr of the socket */

	bacpy(&iso_pi(sk)->src, &hcon->src);



	err = iso_chan_add(conn, sk, NULL);

	if (err)

		goto done;

		goto release;



	if (hcon->state == BT_CONNECTED) {

		iso_sock_clear_timer(sk);
@@ -301,7 +306,11 @@ static int iso_connect_bis(struct sock *sk) 
		iso_sock_set_timer(sk, sk->sk_sndtimeo);

	}



done:

release:

	release_sock(sk);

	return err;



unlock:

	hci_dev_unlock(hdev);

	hci_dev_put(hdev);

	return err;
@@ -325,13 +334,13 @@ static int iso_connect_cis(struct sock *sk) 


	if (!cis_central_capable(hdev)) {

		err = -EOPNOTSUPP;

		goto done;

		goto unlock;

	}



	/* Fail if either PHYs are marked as disabled */

	if (!iso_pi(sk)->qos.in.phy && !iso_pi(sk)->qos.out.phy) {

		err = -EINVAL;

		goto done;

		goto unlock;

	}



	/* Just bind if DEFER_SETUP has been set */
@@ -341,7 +350,7 @@ static int iso_connect_cis(struct sock *sk) 
				    &iso_pi(sk)->qos);

		if (IS_ERR(hcon)) {

			err = PTR_ERR(hcon);

			goto done;

			goto unlock;

		}

	} else {

		hcon = hci_connect_cis(hdev, &iso_pi(sk)->dst,
@@ -349,7 +358,7 @@ static int iso_connect_cis(struct sock *sk) 
				       &iso_pi(sk)->qos);

		if (IS_ERR(hcon)) {

			err = PTR_ERR(hcon);

			goto done;

			goto unlock;

		}

	}
@@ -357,15 +366,20 @@ static int iso_connect_cis(struct sock *sk) 
	if (!conn) {

		hci_conn_drop(hcon);

		err = -ENOMEM;

		goto done;

		goto unlock;

	}



	hci_dev_unlock(hdev);

	hci_dev_put(hdev);



	lock_sock(sk);



	/* Update source addr of the socket */

	bacpy(&iso_pi(sk)->src, &hcon->src);



	err = iso_chan_add(conn, sk, NULL);

	if (err)

		goto done;

		goto release;



	if (hcon->state == BT_CONNECTED) {

		iso_sock_clear_timer(sk);
@@ -378,7 +392,11 @@ static int iso_connect_cis(struct sock *sk) 
		iso_sock_set_timer(sk, sk->sk_sndtimeo);

	}



done:

release:

	release_sock(sk);

	return err;



unlock:

	hci_dev_unlock(hdev);

	hci_dev_put(hdev);

	return err;
@@ -832,20 +850,23 @@ static int iso_sock_connect(struct socket *sock, struct sockaddr *addr, 
	bacpy(&iso_pi(sk)->dst, &sa->iso_bdaddr);

	iso_pi(sk)->dst_type = sa->iso_bdaddr_type;



	release_sock(sk);



	if (bacmp(&iso_pi(sk)->dst, BDADDR_ANY))

		err = iso_connect_cis(sk);

	else

		err = iso_connect_bis(sk);



	if (err)

		goto done;

		return err;



	lock_sock(sk);



	if (!test_bit(BT_SK_DEFER_SETUP, &bt_sk(sk)->flags)) {

		err = bt_sock_wait_state(sk, BT_CONNECTED,

					 sock_sndtimeo(sk, flags & O_NONBLOCK));

	}



done:

	release_sock(sk);

	return err;

}
@@ -1101,28 +1122,22 @@ static int iso_sock_recvmsg(struct socket *sock, struct msghdr *msg, 
{

	struct sock *sk = sock->sk;

	struct iso_pinfo *pi = iso_pi(sk);

	int err;



	BT_DBG("sk %p", sk);



	lock_sock(sk);



	if (test_and_clear_bit(BT_SK_DEFER_SETUP, &bt_sk(sk)->flags)) {

		switch (sk->sk_state) {

		case BT_CONNECT2:

			lock_sock(sk);

			iso_conn_defer_accept(pi->conn->hcon);

			sk->sk_state = BT_CONFIG;

			release_sock(sk);

			return 0;

		case BT_CONNECT:

			err = iso_connect_cis(sk);

			release_sock(sk);

			return err;

			return iso_connect_cis(sk);

		}

	}



	release_sock(sk);



	return bt_sock_recvmsg(sock, msg, len, flags);

}