program: r0 = syz_init_net_socket$bt_l2cap(0x1f, 0x2, 0x0) connect$bt_l2cap(r0, &(0x7f0000000000)={0x1f, 0x8ef, @fixed={'\xaa\xaa\xaa\xaa\xaa', 0x10}}, 0xe) r1 = syz_init_net_socket$bt_bnep(0x1f, 0x3, 0x4) ioctl$sock_bt_bnep_BNEPCONNADD(r1, 0x400442c8, &(0x7f00000001c0)={r0, 0x1, 0x2}) ioctl$sock_bt_bnep_BNEPCONNADD(r1, 0x400442c8, &(0x7f0000000040)={r0, 0x0, 0x4}) socket$nl_generic(0x10, 0x3, 0x10) syz_init_net_socket$bt_hci(0x1f, 0x3, 0x5) close(0x4) r2 = syz_init_net_socket$bt_hci(0x1f, 0x3, 0x1) bind$bt_hci(r2, &(0x7f0000000080)={0x1f, 0xffff, 0x3}, 0x6) r3 = syz_init_net_socket$bt_hci(0x1f, 0x3, 0x1) ioctl$HCIINQUIRY(r3, 0x400448ca, 0x0) [ 101.645993][ T5306] Bluetooth: hci0: command tx timeout [ 101.828512][ T5331] [ 101.829727][ T5331] ====================================================== [ 101.832883][ T5331] WARNING: possible circular locking dependency detected [ 101.835974][ T5331] syzkaller #0 Not tainted [ 101.838025][ T5331] ------------------------------------------------------ [ 101.841221][ T5331] syz.0.0/5331 is trying to acquire lock: [ 101.843903][ T5331] ffff8880374ba040 ((work_completion)(&(&conn->info_timer)->work)){+.+.}-{0:0}, at: __flush_work+0x100/0xc50 [ 101.850854][ T5331] [ 101.850854][ T5331] but task is already holding lock: [ 101.854317][ T5331] ffff8880374ba2f8 (&conn->lock#2){+.+.}-{4:4}, at: l2cap_conn_del+0x7b/0x5c0 [ 101.858429][ T5331] [ 101.858429][ T5331] which lock already depends on the new lock. [ 101.858429][ T5331] [ 101.863098][ T5331] [ 101.863098][ T5331] the existing dependency chain (in reverse order) is: [ 101.867546][ T5331] [ 101.867546][ T5331] -> #1 (&conn->lock#2){+.+.}-{4:4}: [ 101.872017][ T5331] __mutex_lock+0x19f/0x1300 [ 101.874873][ T5331] l2cap_info_timeout+0x60/0xa0 [ 101.877276][ T5331] process_scheduled_works+0xb6e/0x18c0 [ 101.879468][ T5331] worker_thread+0xa53/0xfc0 [ 101.881401][ T5331] kthread+0x388/0x470 [ 101.883181][ T5331] ret_from_fork+0x51e/0xb90 [ 101.885399][ T5331] ret_from_fork_asm+0x1a/0x30 [ 101.887789][ T5331] [ 101.887789][ T5331] -> #0 ((work_completion)(&(&conn->info_timer)->work)){+.+.}-{0:0}: [ 101.892428][ T5331] __lock_acquire+0x15a5/0x2cf0 [ 101.894592][ T5331] lock_acquire+0xf0/0x2e0 [ 101.896562][ T5331] __flush_work+0x700/0xc50 [ 101.899058][ T5331] __cancel_work_sync+0xbe/0x110 [ 101.901505][ T5331] l2cap_conn_del+0x40f/0x5c0 [ 101.903838][ T5331] hci_conn_hash_flush+0x10d/0x260 [ 101.906838][ T5331] hci_dev_close_sync+0x821/0x10e0 [ 101.910099][ T5331] hci_dev_close+0x108/0x260 [ 101.912570][ T5331] sock_do_ioctl+0x101/0x320 [ 101.914794][ T5331] sock_ioctl+0x5c6/0x7f0 [ 101.916641][ T5331] __se_sys_ioctl+0xfc/0x170 [ 101.918837][ T5331] do_syscall_64+0x14d/0xf80 [ 101.920802][ T5331] entry_SYSCALL_64_after_hwframe+0x77/0x7f [ 101.923645][ T5331] [ 101.923645][ T5331] other info that might help us debug this: [ 101.923645][ T5331] [ 101.927829][ T5331] Possible unsafe locking scenario: [ 101.927829][ T5331] [ 101.931197][ T5331] CPU0 CPU1 [ 101.933604][ T5331] ---- ---- [ 101.935935][ T5331] lock(&conn->lock#2); [ 101.937770][ T5331] lock((work_completion)(&(&conn->info_timer)->work)); [ 101.941946][ T5331] lock(&conn->lock#2); [ 101.944997][ T5331] lock((work_completion)(&(&conn->info_timer)->work)); [ 101.948489][ T5331] [ 101.948489][ T5331] *** DEADLOCK *** [ 101.948489][ T5331] [ 101.952404][ T5331] 5 locks held by syz.0.0/5331: [ 101.954428][ T5331] #0: ffff88801edb0ec0 (&hdev->req_lock){+.+.}-{4:4}, at: hci_dev_close+0x100/0x260 [ 101.958449][ T5331] #1: ffff88801edb00c0 (&hdev->lock){+.+.}-{4:4}, at: hci_dev_close_sync+0x640/0x10e0 [ 101.962738][ T5331] #2: ffffffff8fd5ca68 (hci_cb_list_lock){+.+.}-{4:4}, at: hci_conn_hash_flush+0xa1/0x260 [ 101.967778][ T5331] #3: ffff8880374ba2f8 (&conn->lock#2){+.+.}-{4:4}, at: l2cap_conn_del+0x7b/0x5c0 [ 101.971965][ T5331] #4: ffffffff8e75e520 (rcu_read_lock){....}-{1:3}, at: __flush_work+0x100/0xc50 [ 101.975244][ T5331] [ 101.975244][ T5331] stack backtrace: [ 101.977554][ T5331] CPU: 0 UID: 0 PID: 5331 Comm: syz.0.0 Not tainted syzkaller #0 PREEMPT(full) [ 101.977572][ T5331] Hardware name: QEMU Standard PC (Q35 + ICH9, 2009), BIOS 1.16.3-debian-1.16.3-2 04/01/2014 [ 101.977580][ T5331] Call Trace: [ 101.977589][ T5331] [ 101.977596][ T5331] dump_stack_lvl+0xe8/0x150 [ 101.977617][ T5331] print_circular_bug+0x2e1/0x300 [ 101.977631][ T5331] check_noncircular+0x12e/0x150 [ 101.977645][ T5331] __lock_acquire+0x15a5/0x2cf0 [ 101.977657][ T5331] ? do_raw_spin_lock+0x12b/0x2f0 [ 101.977667][ T5331] ? do_raw_spin_unlock+0x4d/0x210 [ 101.977675][ T5331] lock_acquire+0xf0/0x2e0 [ 101.977684][ T5331] ? __flush_work+0x100/0xc50 [ 101.977696][ T5331] ? __flush_work+0x100/0xc50 [ 101.977706][ T5331] __flush_work+0x700/0xc50 [ 101.977717][ T5331] ? __flush_work+0x100/0xc50 [ 101.977732][ T5331] ? __flush_work+0x100/0xc50 [ 101.977747][ T5331] ? __pfx___flush_work+0x10/0x10 [ 101.977761][ T5331] ? __pfx_wq_barrier_func+0x10/0x10 [ 101.977780][ T5331] ? __cancel_work_sync+0x5c/0x110 [ 101.977792][ T5331] __cancel_work_sync+0xbe/0x110 [ 101.977803][ T5331] l2cap_conn_del+0x40f/0x5c0 [ 101.977814][ T5331] ? __pfx_l2cap_disconn_cfm+0x10/0x10 [ 101.977823][ T5331] hci_conn_hash_flush+0x10d/0x260 [ 101.977834][ T5331] hci_dev_close_sync+0x821/0x10e0 [ 101.977845][ T5331] ? __pfx_hci_dev_close_sync+0x10/0x10 [ 101.977854][ T5331] ? lockdep_hardirqs_on+0x7a/0x110 [ 101.977861][ T5331] ? enable_work+0x1fd/0x230 [ 101.977872][ T5331] hci_dev_close+0x108/0x260 [ 101.977882][ T5331] sock_do_ioctl+0x101/0x320 [ 101.977891][ T5331] ? __pfx_sock_do_ioctl+0x10/0x10 [ 101.977899][ T5331] ? do_futex+0x333/0x420 [ 101.977912][ T5331] sock_ioctl+0x5c6/0x7f0 [ 101.977920][ T5331] ? __pfx_sock_ioctl+0x10/0x10 [ 101.977927][ T5331] ? __fget_files+0x2a/0x420 [ 101.977938][ T5331] ? __fget_files+0x3a0/0x420 [ 101.977946][ T5331] ? __fget_files+0x2a/0x420 [ 101.977955][ T5331] ? bpf_lsm_file_ioctl+0x9/0x20 [ 101.977993][ T5331] ? __pfx_sock_ioctl+0x10/0x10 [ 101.978001][ T5331] __se_sys_ioctl+0xfc/0x170 [ 101.978014][ T5331] do_syscall_64+0x14d/0xf80 [ 101.978024][ T5331] ? trace_irq_disable+0x3b/0x150 [ 101.978042][ T5331] ? entry_SYSCALL_64_after_hwframe+0x77/0x7f [ 101.978052][ T5331] ? clear_bhb_loop+0x40/0x90 [ 101.978062][ T5331] entry_SYSCALL_64_after_hwframe+0x77/0x7f [ 101.978070][ T5331] RIP: 0033:0x7f1aa1f9c799 [ 101.978080][ T5331] Code: ff c3 66 2e 0f 1f 84 00 00 00 00 00 0f 1f 44 00 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 e8 ff ff ff f7 d8 64 89 01 48 [ 101.978087][ T5331] RSP: 002b:00007f1aa2e22fe8 EFLAGS: 00000246 ORIG_RAX: 0000000000000010 [ 101.978100][ T5331] RAX: ffffffffffffffda RBX: 00007f1aa2216090 RCX: 00007f1aa1f9c799 [ 101.978108][ T5331] RDX: 0000000000000000 RSI: 00000000400448ca RDI: 0000000000000008 [ 101.978116][ T5331] RBP: 00007f1aa2032c99 R08: 0000000000000000 R09: 0000000000000000 [ 101.978123][ T5331] R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000 [ 101.978128][ T5331] R13: 00007f1aa2216128 R14: 00007f1aa2216090 R15: 00007ffc9e4f2658 [ 101.978139][ T5331] [ 103.665780][ T4671] Bluetooth: hci0: command tx timeout [ 105.745893][ T4671] Bluetooth: hci0: command tx timeout [ 107.825699][ T4671] Bluetooth: hci0: command tx timeout