program: r0 = syz_open_dev$tty1(0xc, 0x4, 0x1) ioctl$KDSETLED(r0, 0x4b32, 0x6) r1 = syz_init_net_socket$bt_l2cap(0x1f, 0x2, 0x0) connect$bt_l2cap(r1, &(0x7f0000000080)={0x1f, 0x0, @fixed={'\xaa\xaa\xaa\xaa\xaa', 0x10}, 0x7ff}, 0xe) r2 = syz_init_net_socket$bt_hidp(0x1f, 0x3, 0x6) ioctl$sock_bt_hidp_HIDPCONNADD(r2, 0x400448c8, &(0x7f00000000c0)={r1, r1, 0x206, 0x0, 0x0, 0x2, 0x72, 0x1, 0x3, 0x7, 0x0, 0x8, 'syz1\x00'}) r3 = syz_init_net_socket$bt_hci(0x1f, 0x3, 0x1) ioctl$sock_bt_hci(r3, 0x400448ca, 0x0) [ 85.843602][ T5329] input: Bluetooth HID Boot Protocol Device as /devices/virtual/bluetooth/hci0/hci0:200/input5 [ 85.967492][ T5330] [ 85.968651][ T5330] ====================================================== [ 85.971562][ T5330] WARNING: possible circular locking dependency detected [ 85.974473][ T5330] syzkaller #0 Not tainted [ 85.976311][ T5330] ------------------------------------------------------ [ 85.979132][ T5330] syz.0.0/5330 is trying to acquire lock: [ 85.981569][ T5330] ffff888044dd2840 ((work_completion)(&(&conn->info_timer)->work)){+.+.}-{0:0}, at: __flush_work+0xd2/0xbc0 [ 85.986341][ T5330] [ 85.986341][ T5330] but task is already holding lock: [ 85.989443][ T5330] ffff888044dd2b38 (&conn->lock#2){+.+.}-{4:4}, at: l2cap_conn_del+0x70/0x680 [ 85.993915][ T5330] [ 85.993915][ T5330] which lock already depends on the new lock. [ 85.993915][ T5330] [ 85.999147][ T5330] [ 85.999147][ T5330] the existing dependency chain (in reverse order) is: [ 86.003476][ T5330] [ 86.003476][ T5330] -> #1 (&conn->lock#2){+.+.}-{4:4}: [ 86.006558][ T5330] lock_acquire+0x120/0x360 [ 86.008719][ T5330] __mutex_lock+0x187/0x1350 [ 86.011030][ T5330] l2cap_info_timeout+0x60/0xa0 [ 86.013246][ T5330] process_scheduled_works+0xae1/0x17b0 [ 86.015912][ T5330] worker_thread+0x8a0/0xda0 [ 86.018033][ T5330] kthread+0x711/0x8a0 [ 86.019979][ T5330] ret_from_fork+0x4bc/0x870 [ 86.022106][ T5330] ret_from_fork_asm+0x1a/0x30 [ 86.024374][ T5330] [ 86.024374][ T5330] -> #0 ((work_completion)(&(&conn->info_timer)->work)){+.+.}-{0:0}: [ 86.028582][ T5330] validate_chain+0xb9b/0x2140 [ 86.030838][ T5330] __lock_acquire+0xab9/0xd20 [ 86.033039][ T5330] lock_acquire+0x120/0x360 [ 86.035133][ T5330] __flush_work+0x6b8/0xbc0 [ 86.037485][ T5330] __cancel_work_sync+0xbe/0x110 [ 86.039779][ T5330] l2cap_conn_del+0x4f0/0x680 [ 86.042031][ T5330] hci_conn_hash_flush+0x10d/0x230 [ 86.044357][ T5330] hci_dev_close_sync+0xaef/0x1330 [ 86.046641][ T5330] hci_dev_close+0x108/0x200 [ 86.048903][ T5330] sock_do_ioctl+0xdc/0x300 [ 86.051070][ T5330] sock_ioctl+0x576/0x790 [ 86.053073][ T5330] __se_sys_ioctl+0xfc/0x170 [ 86.055298][ T5330] do_syscall_64+0xfa/0xfa0 [ 86.057306][ T5330] entry_SYSCALL_64_after_hwframe+0x77/0x7f [ 86.059879][ T5330] [ 86.059879][ T5330] other info that might help us debug this: [ 86.059879][ T5330] [ 86.064001][ T5330] Possible unsafe locking scenario: [ 86.064001][ T5330] [ 86.067028][ T5330] CPU0 CPU1 [ 86.069226][ T5330] ---- ---- [ 86.071574][ T5330] lock(&conn->lock#2); [ 86.073545][ T5330] lock((work_completion)(&(&conn->info_timer)->work)); [ 86.077254][ T5330] lock(&conn->lock#2); [ 86.079979][ T5330] lock((work_completion)(&(&conn->info_timer)->work)); [ 86.082876][ T5330] [ 86.082876][ T5330] *** DEADLOCK *** [ 86.082876][ T5330] [ 86.086164][ T5330] 5 locks held by syz.0.0/5330: [ 86.088248][ T5330] #0: ffff888033580dc8 (&hdev->req_lock){+.+.}-{4:4}, at: hci_dev_close+0x100/0x200 [ 86.092292][ T5330] #1: ffff8880335800b8 (&hdev->lock){+.+.}-{4:4}, at: hci_dev_close_sync+0x66a/0x1330 [ 86.096425][ T5330] #2: ffffffff8f64bce8 (hci_cb_list_lock){+.+.}-{4:4}, at: hci_conn_hash_flush+0xa1/0x230 [ 86.100873][ T5330] #3: ffff888044dd2b38 (&conn->lock#2){+.+.}-{4:4}, at: l2cap_conn_del+0x70/0x680 [ 86.105016][ T5330] #4: ffffffff8e13d2e0 (rcu_read_lock){....}-{1:3}, at: __flush_work+0xd2/0xbc0 [ 86.108929][ T5330] [ 86.108929][ T5330] stack backtrace: [ 86.111303][ T5330] CPU: 0 UID: 0 PID: 5330 Comm: syz.0.0 Not tainted syzkaller #0 PREEMPT(full) [ 86.111314][ T5330] Hardware name: QEMU Standard PC (Q35 + ICH9, 2009), BIOS 1.16.3-debian-1.16.3-2~bpo12+1 04/01/2014 [ 86.111319][ T5330] Call Trace: [ 86.111325][ T5330] [ 86.111329][ T5330] dump_stack_lvl+0x189/0x250 [ 86.111341][ T5330] ? __pfx_dump_stack_lvl+0x10/0x10 [ 86.111348][ T5330] ? __pfx__printk+0x10/0x10 [ 86.111356][ T5330] ? print_lock_name+0xde/0x100 [ 86.111363][ T5330] print_circular_bug+0x2ee/0x310 [ 86.111376][ T5330] check_noncircular+0x134/0x160 [ 86.111387][ T5330] validate_chain+0xb9b/0x2140 [ 86.111398][ T5330] ? do_raw_spin_lock+0x121/0x290 [ 86.111410][ T5330] ? look_up_lock_class+0x74/0x170 [ 86.111419][ T5330] ? register_lock_class+0x51/0x320 [ 86.111434][ T5330] __lock_acquire+0xab9/0xd20 [ 86.111447][ T5330] ? __flush_work+0xd2/0xbc0 [ 86.111456][ T5330] lock_acquire+0x120/0x360 [ 86.111476][ T5330] ? __flush_work+0xd2/0xbc0 [ 86.111486][ T5330] ? _raw_spin_unlock_irq+0x23/0x50 [ 86.111500][ T5330] ? __flush_work+0xd2/0xbc0 [ 86.111509][ T5330] __flush_work+0x6b8/0xbc0 [ 86.111518][ T5330] ? __flush_work+0xd2/0xbc0 [ 86.111527][ T5330] ? __flush_work+0xd2/0xbc0 [ 86.111536][ T5330] ? __pfx___flush_work+0x10/0x10 [ 86.111544][ T5330] ? __pfx_wq_barrier_func+0x10/0x10 [ 86.111561][ T5330] ? __pfx___cancel_work+0x10/0x10 [ 86.111570][ T5330] ? hci_conn_drop+0x14d/0x280 [ 86.111585][ T5330] __cancel_work_sync+0xbe/0x110 [ 86.111595][ T5330] l2cap_conn_del+0x4f0/0x680 [ 86.111608][ T5330] ? __pfx_l2cap_disconn_cfm+0x10/0x10 [ 86.111620][ T5330] hci_conn_hash_flush+0x10d/0x230 [ 86.111633][ T5330] hci_dev_close_sync+0xaef/0x1330 [ 86.111644][ T5330] ? __pfx_hci_dev_close_sync+0x10/0x10 [ 86.111654][ T5330] ? do_raw_read_unlock+0x3d/0x80 [ 86.111665][ T5330] hci_dev_close+0x108/0x200 [ 86.111676][ T5330] sock_do_ioctl+0xdc/0x300 [ 86.111688][ T5330] ? __pfx_sock_do_ioctl+0x10/0x10 [ 86.111736][ T5330] sock_ioctl+0x576/0x790 [ 86.111747][ T5330] ? __pfx_sock_ioctl+0x10/0x10 [ 86.111757][ T5330] ? __fget_files+0x3a0/0x420 [ 86.111770][ T5330] ? __fget_files+0x2a/0x420 [ 86.111785][ T5330] ? bpf_lsm_file_ioctl+0x9/0x20 [ 86.111799][ T5330] ? __pfx_sock_ioctl+0x10/0x10 [ 86.111809][ T5330] __se_sys_ioctl+0xfc/0x170 [ 86.111825][ T5330] do_syscall_64+0xfa/0xfa0 [ 86.111836][ T5330] ? lockdep_hardirqs_on+0x9c/0x150 [ 86.111851][ T5330] ? entry_SYSCALL_64_after_hwframe+0x77/0x7f [ 86.111862][ T5330] ? clear_bhb_loop+0x60/0xb0 [ 86.111873][ T5330] entry_SYSCALL_64_after_hwframe+0x77/0x7f [ 86.111884][ T5330] RIP: 0033:0x7f9c12b8efc9 [ 86.111895][ T5330] Code: ff ff c3 66 2e 0f 1f 84 00 00 00 00 00 0f 1f 40 00 48 89 f8 48 89 f7 48 89 d6 48 89 ca 4d 89 c2 4d 89 c8 4c 8b 4c 24 08 0f 05 <48> 3d 01 f0 ff ff 73 01 c3 48 c7 c1 a8 ff ff ff f7 d8 64 89 01 48 [ 86.111905][ T5330] RSP: 002b:00007f9c0eff5038 EFLAGS: 00000246 ORIG_RAX: 0000000000000010 [ 86.111918][ T5330] RAX: ffffffffffffffda RBX: 00007f9c12de6090 RCX: 00007f9c12b8efc9 [ 86.111927][ T5330] RDX: 0000000000000000 RSI: 00000000400448ca RDI: 0000000000000007 [ 86.111934][ T5330] RBP: 00007f9c12c11f91 R08: 0000000000000000 R09: 0000000000000000 [ 86.111941][ T5330] R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000 [ 86.111948][ T5330] R13: 00007f9c12de6128 R14: 00007f9c12de6090 R15: 00007ffce6aa1838 [ 86.111960][ T5330] [ 86.262601][ T4670] Bluetooth: hci0: command tx timeout [ 86.553533][ T55] cfg80211: failed to load regulatory.db [ 88.312316][ T4670] Bluetooth: hci0: command tx timeout [ 90.392476][ T4670] Bluetooth: hci0: command tx timeout