This fixes the circular locking dependency warning below, by
releasing the socket lock before enterning iso_listen_bis, to
avoid any potential deadlock with hdev lock.
[ 75.307983] ======================================================
[ 75.307984] WARNING: possible circular locking dependency detected
[ 75.307985] 6.12.0-rc6+ #22 Not tainted
[ 75.307987] ------------------------------------------------------
[ 75.307987] kworker/u81:2/2623 is trying to acquire lock:
[ 75.307988] ffff8fde1769da58 (sk_lock-AF_BLUETOOTH-BTPROTO_ISO)
at: iso_connect_cfm+0x253/0x840 [bluetooth]
[ 75.308021]
but task is already holding lock:
[ 75.308022] ffff8fdd61a10078 (&hdev->lock)
at: hci_le_per_adv_report_evt+0x47/0x2f0 [bluetooth]
[ 75.308053]
which lock already depends on the new lock.
[ 75.308054]
the existing dependency chain (in reverse order) is:
[ 75.308055]
-> #1 (&hdev->lock){+.+.}-{3:3}:
[ 75.308057] __mutex_lock+0xad/0xc50
[ 75.308061] mutex_lock_nested+0x1b/0x30
[ 75.308063] iso_sock_listen+0x143/0x5c0 [bluetooth]
[ 75.308085] __sys_listen_socket+0x49/0x60
[ 75.308088] __x64_sys_listen+0x4c/0x90
[ 75.308090] x64_sys_call+0x2517/0x25f0
[ 75.308092] do_syscall_64+0x87/0x150
[ 75.308095] entry_SYSCALL_64_after_hwframe+0x76/0x7e
[ 75.308098]
-> #0 (sk_lock-AF_BLUETOOTH-BTPROTO_ISO){+.+.}-{0:0}:
[ 75.308100] __lock_acquire+0x155e/0x25f0
[ 75.308103] lock_acquire+0xc9/0x300
[ 75.308105] lock_sock_nested+0x32/0x90
[ 75.308107] iso_connect_cfm+0x253/0x840 [bluetooth]
[ 75.308128] hci_connect_cfm+0x6c/0x190 [bluetooth]
[ 75.308155] hci_le_per_adv_report_evt+0x27b/0x2f0 [bluetooth]
[ 75.308180] hci_le_meta_evt+0xe7/0x200 [bluetooth]
[ 75.308206] hci_event_packet+0x21f/0x5c0 [bluetooth]
[ 75.308230] hci_rx_work+0x3ae/0xb10 [bluetooth]
[ 75.308254] process_one_work+0x212/0x740
[ 75.308256] worker_thread+0x1bd/0x3a0
[ 75.308258] kthread+0xe4/0x120
[ 75.308259] ret_from_fork+0x44/0x70
[ 75.308261] ret_from_fork_asm+0x1a/0x30
[ 75.308263]
other info that might help us debug this:
[ 75.308264] Possible unsafe locking scenario:
[ 75.308264] CPU0 CPU1
[ 75.308265] ---- ----
[ 75.308265] lock(&hdev->lock);
[ 75.308267] lock(sk_lock-
AF_BLUETOOTH-BTPROTO_ISO);
[ 75.308268] lock(&hdev->lock);
[ 75.308269] lock(sk_lock-AF_BLUETOOTH-BTPROTO_ISO);
[ 75.308270]
*** DEADLOCK ***
[ 75.308271] 4 locks held by kworker/u81:2/2623:
[ 75.308272] #0: ffff8fdd66e52148 ((wq_completion)hci0#2){+.+.}-{0:0},
at: process_one_work+0x443/0x740
[ 75.308276] #1: ffffafb488b7fe48 ((work_completion)(&hdev->rx_work)),
at: process_one_work+0x1ce/0x740
[ 75.308280] #2: ffff8fdd61a10078 (&hdev->lock){+.+.}-{3:3}
at: hci_le_per_adv_report_evt+0x47/0x2f0 [bluetooth]
[ 75.308304] #3: ffffffffb6ba4900 (rcu_read_lock){....}-{1:2},
at: hci_connect_cfm+0x29/0x190 [bluetooth]
Fixes: 02171da6e86a ("Bluetooth: ISO: Add hcon for listening bis sk")
Signed-off-by: Iulia Tanasescu <iulia.tanasescu@xxxxxxx>
---
net/bluetooth/iso.c | 14 ++++++++++++--
1 file changed, 12 insertions(+), 2 deletions(-)
diff --git a/net/bluetooth/iso.c b/net/bluetooth/iso.c
index 5ca381a3b04b..ed559c82d353 100644
--- a/net/bluetooth/iso.c
+++ b/net/bluetooth/iso.c
@@ -1129,6 +1129,7 @@ static int iso_listen_bis(struct sock *sk)
return -EHOSTUNREACH;
hci_dev_lock(hdev);
+ lock_sock(sk);
/* Fail if user set invalid QoS */
if (iso_pi(sk)->qos_user_set && !check_bcast_qos(&iso_pi(sk)->qos)) {
@@ -1159,6 +1160,7 @@ static int iso_listen_bis(struct sock *sk)
}
unlock:
+ release_sock(sk);
hci_dev_unlock(hdev);
hci_dev_put(hdev);
return err;
@@ -1187,6 +1189,7 @@ static int iso_sock_listen(struct socket *sock, int backlog)
BT_DBG("sk %p backlog %d", sk, backlog);
+ sock_hold(sk);
lock_sock(sk);
if (sk->sk_state != BT_BOUND) {
@@ -1199,10 +1202,16 @@ static int iso_sock_listen(struct socket *sock, int backlog)
goto done;
}
- if (!bacmp(&iso_pi(sk)->dst, BDADDR_ANY))
+ if (!bacmp(&iso_pi(sk)->dst, BDADDR_ANY)) {
err = iso_listen_cis(sk);
- else
+ } else {
+ /* Drop sock lock to avoid potential
+ * deadlock with the hdev lock.
+ */
+ release_sock(sk);
err = iso_listen_bis(sk);
+ lock_sock(sk);
+ }
if (err)
goto done;
@@ -1214,6 +1223,7 @@ static int iso_sock_listen(struct socket *sock, int backlog)
done:
release_sock(sk);
+ sock_put(sk);
return err;
}
--
2.43.0
