program: socketpair$unix(0x1, 0x2, 0x0, &(0x7f0000000200)) r0 = openat$tun(0xffffffffffffff9c, &(0x7f00000001c0), 0x48e02, 0x0) close(r0) openat$cuse(0xffffffffffffff9c, &(0x7f0000000340), 0x2, 0x0) io_setup(0x1, &(0x7f0000000040)) sendmsg$IPCTNL_MSG_TIMEOUT_NEW(0xffffffffffffffff, &(0x7f0000000180)={0x0, 0x0, &(0x7f0000000140)={&(0x7f0000000200)=ANY=[@ANYBLOB="14"], 0x14}, 0x1, 0x0, 0x0, 0x4810}, 0x8000) r1 = syz_init_net_socket$bt_l2cap(0x1f, 0x2, 0x0) connect$bt_l2cap(r1, &(0x7f0000000000)={0x1f, 0x8ef, @fixed={'\xaa\xaa\xaa\xaa\xaa', 0x10}}, 0xe) r2 = syz_init_net_socket$bt_bnep(0x1f, 0x3, 0x4) ioctl$sock_bt_bnep_BNEPCONNADD(r2, 0x400442c8, &(0x7f00000001c0)={r1, 0x1, 0x2}) r3 = syz_init_net_socket$bt_bnep(0x1f, 0x3, 0x4) ioctl$sock_bt_bnep_BNEPGETCONNLIST(r3, 0x800442d2, &(0x7f0000000040)={0xfffffffffffffdff, 0x0}) r4 = syz_init_net_socket$bt_hci(0x1f, 0x3, 0x1) ioctl$HCIINQUIRY(r4, 0x400448ca, 0x0) ioctl$HCIINQUIRY(0xffffffffffffffff, 0x400448ca, 0x0) [ 87.314039][ T9] cfg80211: failed to load regulatory.db [ 87.451916][ T5330] [ 87.452864][ T5330] ====================================================== [ 87.455508][ T5330] WARNING: possible circular locking dependency detected [ 87.458240][ T5330] syzkaller #0 Not tainted [ 87.459995][ T5330] ------------------------------------------------------ [ 87.463025][ T5330] syz.0.0/5330 is trying to acquire lock: [ 87.465418][ T5330] ffff88803583a840 ((work_completion)(&(&conn->info_timer)->work)){+.+.}-{0:0}, at: __flush_work+0xd2/0xbc0 [ 87.470089][ T5330] [ 87.470089][ T5330] but task is already holding lock: [ 87.473228][ T5330] ffff88803583ab38 (&conn->lock#2){+.+.}-{4:4}, at: l2cap_conn_del+0x70/0x680 [ 87.477107][ T5330] [ 87.477107][ T5330] which lock already depends on the new lock. [ 87.477107][ T5330] [ 87.482593][ T5330] [ 87.482593][ T5330] the existing dependency chain (in reverse order) is: [ 87.486934][ T5330] [ 87.486934][ T5330] -> #1 (&conn->lock#2){+.+.}-{4:4}: [ 87.490403][ T5330] lock_acquire+0x120/0x360 [ 87.492776][ T5330] __mutex_lock+0x187/0x1350 [ 87.495120][ T5330] l2cap_info_timeout+0x60/0xa0 [ 87.497460][ T5330] process_scheduled_works+0xae1/0x17b0 [ 87.500381][ T5330] worker_thread+0x8a0/0xda0 [ 87.502608][ T5330] kthread+0x711/0x8a0 [ 87.504569][ T5330] ret_from_fork+0x4bc/0x870 [ 87.506869][ T5330] ret_from_fork_asm+0x1a/0x30 [ 87.508992][ T5330] [ 87.508992][ T5330] -> #0 ((work_completion)(&(&conn->info_timer)->work)){+.+.}-{0:0}: [ 87.513338][ T5330] validate_chain+0xb9b/0x2140 [ 87.515659][ T5330] __lock_acquire+0xab9/0xd20 [ 87.517891][ T5330] lock_acquire+0x120/0x360 [ 87.520053][ T5330] __flush_work+0x6b8/0xbc0 [ 87.522217][ T5330] __cancel_work_sync+0xbe/0x110 [ 87.524556][ T5330] l2cap_conn_del+0x4f0/0x680 [ 87.526771][ T5330] hci_conn_hash_flush+0x10d/0x230 [ 87.529164][ T5330] hci_dev_close_sync+0xaef/0x1330 [ 87.531530][ T5330] hci_dev_close+0x108/0x200 [ 87.533696][ T5330] sock_do_ioctl+0xdc/0x300 [ 87.535476][ T5330] sock_ioctl+0x576/0x790 [ 87.537455][ T5330] __se_sys_ioctl+0xfc/0x170 [ 87.539767][ T5330] do_syscall_64+0xfa/0xfa0 [ 87.542028][ T5330] entry_SYSCALL_64_after_hwframe+0x77/0x7f [ 87.544660][ T5330] [ 87.544660][ T5330] other info that might help us debug this: [ 87.544660][ T5330] [ 87.548914][ T5330] Possible unsafe locking scenario: [ 87.548914][ T5330] [ 87.551974][ T5330] CPU0 CPU1 [ 87.554135][ T5330] ---- ---- [ 87.556193][ T5330] lock(&conn->lock#2); [ 87.557872][ T5330] lock((work_completion)(&(&conn->info_timer)->work)); [ 87.561558][ T5330] lock(&conn->lock#2); [ 87.564249][ T5330] lock((work_completion)(&(&conn->info_timer)->work)); [ 87.567123][ T5330] [ 87.567123][ T5330] *** DEADLOCK *** [ 87.567123][ T5330] [ 87.570415][ T5330] 5 locks held by syz.0.0/5330: [ 87.572510][ T5330] #0: ffff888000b04dc8 (&hdev->req_lock){+.+.}-{4:4}, at: hci_dev_close+0x100/0x200 [ 87.576382][ T5330] #1: ffff888000b040b8 (&hdev->lock){+.+.}-{4:4}, at: hci_dev_close_sync+0x66a/0x1330 [ 87.580159][ T5330] #2: ffffffff8f438268 (hci_cb_list_lock){+.+.}-{4:4}, at: hci_conn_hash_flush+0xa1/0x230 [ 87.584352][ T5330] #3: ffff88803583ab38 (&conn->lock#2){+.+.}-{4:4}, at: l2cap_conn_del+0x70/0x680 [ 87.588300][ T5330] #4: ffffffff8df3d0a0 (rcu_read_lock){....}-{1:3}, at: __flush_work+0xd2/0xbc0 [ 87.593211][ T5330] [ 87.593211][ T5330] stack backtrace: [ 87.596608][ T5330] CPU: 0 UID: 0 PID: 5330 Comm: syz.0.0 Not tainted syzkaller #0 PREEMPT(full) [ 87.596627][ T5330] Hardware name: QEMU Standard PC (Q35 + ICH9, 2009), BIOS 1.16.3-debian-1.16.3-2~bpo12+1 04/01/2014 [ 87.596636][ T5330] Call Trace: [ 87.596643][ T5330] [ 87.596650][ T5330] dump_stack_lvl+0x189/0x250 [ 87.596673][ T5330] ? __pfx_dump_stack_lvl+0x10/0x10 [ 87.596691][ T5330] ? __pfx__printk+0x10/0x10 [ 87.596704][ T5330] ? print_lock_name+0xde/0x100 [ 87.596717][ T5330] print_circular_bug+0x2ee/0x310 [ 87.596734][ T5330] check_noncircular+0x134/0x160 [ 87.596751][ T5330] validate_chain+0xb9b/0x2140 [ 87.596766][ T5330] ? do_raw_spin_lock+0x121/0x290 [ 87.596787][ T5330] ? look_up_lock_class+0x74/0x170 [ 87.596802][ T5330] ? register_lock_class+0x51/0x320 [ 87.596817][ T5330] __lock_acquire+0xab9/0xd20 [ 87.596832][ T5330] ? __flush_work+0xd2/0xbc0 [ 87.596849][ T5330] lock_acquire+0x120/0x360 [ 87.596862][ T5330] ? __flush_work+0xd2/0xbc0 [ 87.596878][ T5330] ? _raw_spin_unlock_irq+0x23/0x50 [ 87.596892][ T5330] ? __flush_work+0xd2/0xbc0 [ 87.596907][ T5330] __flush_work+0x6b8/0xbc0 [ 87.596919][ T5330] ? __flush_work+0xd2/0xbc0 [ 87.596932][ T5330] ? __flush_work+0xd2/0xbc0 [ 87.596945][ T5330] ? __pfx___flush_work+0x10/0x10 [ 87.596958][ T5330] ? __pfx_wq_barrier_func+0x10/0x10 [ 87.596973][ T5330] ? __pfx___cancel_work+0x10/0x10 [ 87.596987][ T5330] ? hci_conn_drop+0x14d/0x280 [ 87.597004][ T5330] __cancel_work_sync+0xbe/0x110 [ 87.597017][ T5330] l2cap_conn_del+0x4f0/0x680 [ 87.597032][ T5330] ? __pfx_l2cap_disconn_cfm+0x10/0x10 [ 87.597046][ T5330] hci_conn_hash_flush+0x10d/0x230 [ 87.597062][ T5330] hci_dev_close_sync+0xaef/0x1330 [ 87.597076][ T5330] ? __pfx_hci_dev_close_sync+0x10/0x10 [ 87.597088][ T5330] ? do_raw_read_unlock+0x3d/0x80 [ 87.597105][ T5330] hci_dev_close+0x108/0x200 [ 87.597118][ T5330] sock_do_ioctl+0xdc/0x300 [ 87.597135][ T5330] ? __pfx_sock_do_ioctl+0x10/0x10 [ 87.597156][ T5330] sock_ioctl+0x576/0x790 [ 87.597171][ T5330] ? __pfx_sock_ioctl+0x10/0x10 [ 87.597186][ T5330] ? __fget_files+0x3a0/0x420 [ 87.597195][ T5330] ? __fget_files+0x2a/0x420 [ 87.597205][ T5330] ? bpf_lsm_file_ioctl+0x9/0x20 [ 87.597217][ T5330] ? __pfx_sock_ioctl+0x10/0x10 [ 87.597231][ T5330] __se_sys_ioctl+0xfc/0x170 [ 87.597245][ T5330] do_syscall_64+0xfa/0xfa0 [ 87.597257][ T5330] ? lockdep_hardirqs_on+0x9c/0x150 [ 87.597269][ T5330] ? entry_SYSCALL_64_after_hwframe+0x77/0x7f [ 87.597280][ T5330] ? clear_bhb_loop+0x60/0xb0 [ 87.597291][ T5330] entry_SYSCALL_64_after_hwframe+0x77/0x7f [ 87.597302][ T5330] RIP: 0033:0x7f08b918f7c9 [ 87.597314][ 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 [ 87.597323][ T5330] RSP: 002b:00007f08b9fab038 EFLAGS: 00000246 ORIG_RAX: 0000000000000010 [ 87.597336][ T5330] RAX: ffffffffffffffda RBX: 00007f08b93e5fa0 RCX: 00007f08b918f7c9 [ 87.597344][ T5330] RDX: 0000000000000000 RSI: 00000000400448ca RDI: 000000000000000a [ 87.597352][ T5330] RBP: 00007f08b9213f91 R08: 0000000000000000 R09: 0000000000000000 [ 87.597359][ T5330] R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000 [ 87.597365][ T5330] R13: 00007f08b93e6038 R14: 00007f08b93e5fa0 R15: 00007ffdec9f7048 [ 87.597378][ T5330] [ 87.793157][ T5309] Bluetooth: hci0: command tx timeout [ 89.841263][ T5309] Bluetooth: hci0: command tx timeout [ 91.921488][ T5309] Bluetooth: hci0: command tx timeout