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506d9b4099
This attempts to fix the following trace:
iso-tester/52 is trying to acquire lock:
ffff8880024e0070 (&hdev->lock){+.+.}-{3:3}, at:
iso_sock_listen+0x29e/0x440
but task is already holding lock:
ffff888001978130 (sk_lock-AF_BLUETOOTH-BTPROTO_ISO){+.+.}-{0:0}, at:
iso_sock_listen+0x8b/0x440
which lock already depends on the new lock.
the existing dependency chain (in reverse order) is:
-> #2 (sk_lock-AF_BLUETOOTH-BTPROTO_ISO){+.+.}-{0:0}:
lock_acquire+0x176/0x3d0
lock_sock_nested+0x32/0x80
iso_connect_cfm+0x1a3/0x630
hci_cc_le_setup_iso_path+0x195/0x340
hci_cmd_complete_evt+0x1ae/0x500
hci_event_packet+0x38e/0x7c0
hci_rx_work+0x34c/0x980
process_one_work+0x5a5/0x9a0
worker_thread+0x89/0x6f0
kthread+0x14e/0x180
ret_from_fork+0x22/0x30
-> #1 (hci_cb_list_lock){+.+.}-{3:3}:
lock_acquire+0x176/0x3d0
__mutex_lock+0x13b/0xf50
hci_le_remote_feat_complete_evt+0x17e/0x320
hci_event_packet+0x38e/0x7c0
hci_rx_work+0x34c/0x980
process_one_work+0x5a5/0x9a0
worker_thread+0x89/0x6f0
kthread+0x14e/0x180
ret_from_fork+0x22/0x30
-> #0 (&hdev->lock){+.+.}-{3:3}:
check_prev_add+0xfc/0x1190
__lock_acquire+0x1e27/0x2750
lock_acquire+0x176/0x3d0
__mutex_lock+0x13b/0xf50
iso_sock_listen+0x29e/0x440
__sys_listen+0xe6/0x160
__x64_sys_listen+0x25/0x30
do_syscall_64+0x42/0x90
entry_SYSCALL_64_after_hwframe+0x62/0xcc
other info that might help us debug this:
Chain exists of:
&hdev->lock --> hci_cb_list_lock --> sk_lock-AF_BLUETOOTH-BTPROTO_ISO
Possible unsafe locking scenario:
CPU0 CPU1
---- ----
lock(sk_lock-AF_BLUETOOTH-BTPROTO_ISO);
lock(hci_cb_list_lock);
lock(sk_lock-AF_BLUETOOTH-BTPROTO_ISO);
lock(&hdev->lock);
*** DEADLOCK ***
1 lock held by iso-tester/52:
#0: ffff888001978130 (sk_lock-AF_BLUETOOTH-BTPROTO_ISO){+.+.}-{0:0}, at:
iso_sock_listen+0x8b/0x440
Fixes: f764a6c2c1 ("Bluetooth: ISO: Add broadcast support")
Signed-off-by: Luiz Augusto von Dentz <luiz.von.dentz@intel.com>
Linux kernel
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