program: r0 = syz_init_net_socket$bt_l2cap(0x1f, 0x3, 0x0) connect$bt_l2cap(r0, &(0x7f0000000080)={0x1f, 0x0, @fixed={'\xaa\xaa\xaa\xaa\xaa', 0x10}, 0x803}, 0xe) syz_emit_vhci(&(0x7f0000000340)=ANY=[@ANYBLOB="02c82028002400010007d3040007c4faff020c04000300d3"], 0x2d) r1 = syz_init_net_socket$bt_hci(0x1f, 0x3, 0x1) ioctl$HCIINQUIRY(r1, 0x400448ca, 0x0) [ 107.552073][ T5300] Bluetooth: hci0: command tx timeout [ 107.575610][ T5320] [ 107.576856][ T5320] ====================================================== [ 107.580847][ T5320] WARNING: possible circular locking dependency detected [ 107.591544][ T5320] syzkaller #0 Not tainted [ 107.594248][ T5320] ------------------------------------------------------ [ 107.598053][ T5320] syz.0.0/5320 is trying to acquire lock: [ 107.600657][ T5320] ffff88803701f040 ((work_completion)(&(&conn->info_timer)->work)){+.+.}-{0:0}, at: __flush_work+0x100/0xc50 [ 107.605748][ T5320] [ 107.605748][ T5320] but task is already holding lock: [ 107.609219][ T5320] ffff88803701f2f8 (&conn->lock#2){+.+.}-{4:4}, at: l2cap_conn_del+0x7b/0x5c0 [ 107.614858][ T5320] [ 107.614858][ T5320] which lock already depends on the new lock. [ 107.614858][ T5320] [ 107.619680][ T5320] [ 107.619680][ T5320] the existing dependency chain (in reverse order) is: [ 107.623741][ T5320] [ 107.623741][ T5320] -> #1 (&conn->lock#2){+.+.}-{4:4}: [ 107.626882][ T5320] __mutex_lock+0x19f/0x1300 [ 107.629280][ T5320] l2cap_info_timeout+0x60/0xa0 [ 107.631746][ T5320] process_scheduled_works+0xb02/0x1830 [ 107.634622][ T5320] worker_thread+0xa50/0xfc0 [ 107.636892][ T5320] kthread+0x388/0x470 [ 107.638980][ T5320] ret_from_fork+0x51e/0xb90 [ 107.641263][ T5320] ret_from_fork_asm+0x1a/0x30 [ 107.643475][ T5320] [ 107.643475][ T5320] -> #0 ((work_completion)(&(&conn->info_timer)->work)){+.+.}-{0:0}: [ 107.648021][ T5320] __lock_acquire+0x15a5/0x2cf0 [ 107.650461][ T5320] lock_acquire+0xf0/0x2e0 [ 107.652639][ T5320] __flush_work+0x700/0xc50 [ 107.654857][ T5320] __cancel_work_sync+0xbe/0x110 [ 107.657379][ T5320] l2cap_conn_del+0x40f/0x5c0 [ 107.660128][ T5320] hci_conn_hash_flush+0x10d/0x260 [ 107.663501][ T5320] hci_dev_close_sync+0x821/0x10e0 [ 107.666931][ T5320] hci_dev_close+0x108/0x260 [ 107.669370][ T5320] sock_do_ioctl+0x101/0x320 [ 107.671758][ T5320] sock_ioctl+0x5c6/0x7f0 [ 107.673900][ T5320] __se_sys_ioctl+0xfc/0x170 [ 107.676166][ T5320] do_syscall_64+0x14d/0xf80 [ 107.678496][ T5320] entry_SYSCALL_64_after_hwframe+0x77/0x7f [ 107.682087][ T5320] [ 107.682087][ T5320] other info that might help us debug this: [ 107.682087][ T5320] [ 107.687567][ T5320] Possible unsafe locking scenario: [ 107.687567][ T5320] [ 107.691061][ T5320] CPU0 CPU1 [ 107.693600][ T5320] ---- ---- [ 107.696127][ T5320] lock(&conn->lock#2); [ 107.698346][ T5320] lock((work_completion)(&(&conn->info_timer)->work)); [ 107.702865][ T5320] lock(&conn->lock#2); [ 107.705744][ T5320] lock((work_completion)(&(&conn->info_timer)->work)); [ 107.708666][ T5320] [ 107.708666][ T5320] *** DEADLOCK *** [ 107.708666][ T5320] [ 107.712405][ T5320] 5 locks held by syz.0.0/5320: [ 107.714620][ T5320] #0: ffff888034ad8ec0 (&hdev->req_lock){+.+.}-{4:4}, at: hci_dev_close+0x100/0x260 [ 107.718856][ T5320] #1: ffff888034ad80c0 (&hdev->lock){+.+.}-{4:4}, at: hci_dev_close_sync+0x640/0x10e0 [ 107.723176][ T5320] #2: ffffffff8fd5d7e8 (hci_cb_list_lock){+.+.}-{4:4}, at: hci_conn_hash_flush+0xa1/0x260 [ 107.728411][ T5320] #3: ffff88803701f2f8 (&conn->lock#2){+.+.}-{4:4}, at: l2cap_conn_del+0x7b/0x5c0 [ 107.733359][ T5320] #4: ffffffff8e7602e0 (rcu_read_lock){....}-{1:3}, at: __flush_work+0x100/0xc50 [ 107.737868][ T5320] [ 107.737868][ T5320] stack backtrace: [ 107.740689][ T5320] CPU: 0 UID: 0 PID: 5320 Comm: syz.0.0 Not tainted syzkaller #0 PREEMPT(full) [ 107.740711][ T5320] Hardware name: QEMU Standard PC (Q35 + ICH9, 2009), BIOS 1.16.3-debian-1.16.3-2 04/01/2014 [ 107.740721][ T5320] Call Trace: [ 107.740731][ T5320] [ 107.740737][ T5320] dump_stack_lvl+0xe8/0x150 [ 107.740765][ T5320] print_circular_bug+0x2e1/0x300 [ 107.740783][ T5320] check_noncircular+0x12e/0x150 [ 107.740800][ T5320] __lock_acquire+0x15a5/0x2cf0 [ 107.740814][ T5320] ? do_raw_spin_lock+0x12b/0x2f0 [ 107.740826][ T5320] ? do_raw_spin_unlock+0x4d/0x210 [ 107.740838][ T5320] lock_acquire+0xf0/0x2e0 [ 107.740850][ T5320] ? __flush_work+0x100/0xc50 [ 107.740867][ T5320] ? __flush_work+0x100/0xc50 [ 107.740881][ T5320] __flush_work+0x700/0xc50 [ 107.740897][ T5320] ? __flush_work+0x100/0xc50 [ 107.740911][ T5320] ? __flush_work+0x100/0xc50 [ 107.740926][ T5320] ? __pfx___flush_work+0x10/0x10 [ 107.740941][ T5320] ? __pfx_wq_barrier_func+0x10/0x10 [ 107.740959][ T5320] ? __cancel_work_sync+0x5c/0x110 [ 107.740975][ T5320] __cancel_work_sync+0xbe/0x110 [ 107.741000][ T5320] l2cap_conn_del+0x40f/0x5c0 [ 107.741028][ T5320] ? __pfx_l2cap_disconn_cfm+0x10/0x10 [ 107.741043][ T5320] hci_conn_hash_flush+0x10d/0x260 [ 107.741066][ T5320] hci_dev_close_sync+0x821/0x10e0 [ 107.741082][ T5320] ? __pfx_hci_dev_close_sync+0x10/0x10 [ 107.741093][ T5320] ? lockdep_hardirqs_on+0x7a/0x110 [ 107.741108][ T5320] ? enable_work+0x1fd/0x230 [ 107.741124][ T5320] hci_dev_close+0x108/0x260 [ 107.741136][ T5320] sock_do_ioctl+0x101/0x320 [ 107.741149][ T5320] ? __pfx_sock_do_ioctl+0x10/0x10 [ 107.741160][ T5320] ? do_futex+0x395/0x420 [ 107.741184][ T5320] sock_ioctl+0x5c6/0x7f0 [ 107.741196][ T5320] ? __pfx_sock_ioctl+0x10/0x10 [ 107.741205][ T5320] ? __fget_files+0x2a/0x420 [ 107.741222][ T5320] ? __fget_files+0x3a0/0x420 [ 107.741236][ T5320] ? __fget_files+0x2a/0x420 [ 107.741253][ T5320] ? bpf_lsm_file_ioctl+0x9/0x20 [ 107.741270][ T5320] ? __pfx_sock_ioctl+0x10/0x10 [ 107.741278][ T5320] __se_sys_ioctl+0xfc/0x170 [ 107.741287][ T5320] do_syscall_64+0x14d/0xf80 [ 107.741297][ T5320] ? trace_irq_disable+0x3b/0x150 [ 107.741307][ T5320] ? entry_SYSCALL_64_after_hwframe+0x77/0x7f [ 107.741316][ T5320] ? clear_bhb_loop+0x40/0x90 [ 107.741325][ T5320] entry_SYSCALL_64_after_hwframe+0x77/0x7f [ 107.741336][ T5320] RIP: 0033:0x7f87e7d9c799 [ 107.741349][ T5320] 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 [ 107.741358][ T5320] RSP: 002b:00007f87e8cc4fe8 EFLAGS: 00000246 ORIG_RAX: 0000000000000010 [ 107.741371][ T5320] RAX: ffffffffffffffda RBX: 00007f87e8015fa0 RCX: 00007f87e7d9c799 [ 107.741382][ T5320] RDX: 0000000000000000 RSI: 00000000400448ca RDI: 0000000000000005 [ 107.741388][ T5320] RBP: 00007f87e7e32bd9 R08: 0000000000000000 R09: 0000000000000000 [ 107.741395][ T5320] R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000 [ 107.741401][ T5320] R13: 00007f87e8016038 R14: 00007f87e8015fa0 R15: 00007fffcf866248 [ 107.741412][ T5320] [ 109.605122][ T5300] Bluetooth: hci0: command tx timeout [ 111.685625][ T5300] Bluetooth: hci0: command tx timeout