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Bluetooth: ISO: Avoid circular locking dependency
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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: Luiz Augusto von Dentz <luiz.von.dentz@intel.com>
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Vudentz committed Dec 12, 2022
1 parent 0ba1896 commit 241f519
Showing 1 changed file with 38 additions and 23 deletions.
61 changes: 38 additions & 23 deletions net/bluetooth/iso.c
Original file line number Diff line number Diff line change
Expand Up @@ -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,
Expand All @@ -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);
Expand All @@ -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;
Expand All @@ -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 */
Expand All @@ -341,31 +350,36 @@ 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,
le_addr_type(iso_pi(sk)->dst_type),
&iso_pi(sk)->qos);
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);
Expand All @@ -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;
Expand Down Expand Up @@ -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;
}
Expand Down Expand Up @@ -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);
}

Expand Down

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