Warning: Permanently added '10.128.10.15' (ECDSA) to the list of known hosts. executing program [ 37.111446] [ 37.113223] ====================================================== [ 37.119533] WARNING: possible circular locking dependency detected [ 37.125831] 4.20.0-rc1-next-20181109+ #110 Not tainted [ 37.131083] ------------------------------------------------------ [ 37.137378] kworker/1:2/2789 is trying to acquire lock: [ 37.142728] 00000000ec52d6d2 (&mdev->req_queue_mutex){+.+.}, at: v4l2_release+0x1d7/0x3a0 [ 37.151045] [ 37.151045] but task is already holding lock: [ 37.157005] 0000000027ffdd5c ((delayed_fput_work).work){+.+.}, at: process_one_work+0xb9a/0x1c40 [ 37.165954] [ 37.165954] which lock already depends on the new lock. [ 37.165954] [ 37.174251] [ 37.174251] the existing dependency chain (in reverse order) is: [ 37.181852] [ 37.181852] -> #3 ((delayed_fput_work).work){+.+.}: [ 37.188343] process_one_work+0xc0a/0x1c40 [ 37.193092] worker_thread+0x17f/0x1390 [ 37.197571] kthread+0x35a/0x440 [ 37.201454] ret_from_fork+0x3a/0x50 [ 37.205677] [ 37.205677] -> #2 ((wq_completion)"events"){+.+.}: [ 37.212079] flush_workqueue+0x30a/0x1e10 [ 37.216735] vim2m_stop_streaming+0x7c/0x2c0 [ 37.221678] __vb2_queue_cancel+0x171/0xd20 [ 37.226507] vb2_core_queue_release+0x26/0x80 [ 37.231506] vb2_queue_release+0x15/0x20 [ 37.236089] v4l2_m2m_ctx_release+0x1e/0x35 [ 37.240923] vim2m_release+0xe6/0x150 [ 37.245232] v4l2_release+0x224/0x3a0 [ 37.249547] __fput+0x3bc/0xa70 [ 37.253347] ____fput+0x15/0x20 [ 37.257161] task_work_run+0x1e8/0x2a0 [ 37.261557] exit_to_usermode_loop+0x318/0x380 [ 37.266653] do_syscall_64+0x6be/0x820 [ 37.271079] entry_SYSCALL_64_after_hwframe+0x49/0xbe [ 37.276765] [ 37.276765] -> #1 (&dev->dev_mutex){+.+.}: [ 37.282466] __mutex_lock+0x166/0x16f0 [ 37.286859] mutex_lock_nested+0x16/0x20 [ 37.291432] vim2m_release+0xbc/0x150 [ 37.295739] v4l2_release+0x224/0x3a0 [ 37.300043] __fput+0x3bc/0xa70 [ 37.303826] ____fput+0x15/0x20 [ 37.307607] task_work_run+0x1e8/0x2a0 [ 37.311998] exit_to_usermode_loop+0x318/0x380 [ 37.317084] do_syscall_64+0x6be/0x820 [ 37.321486] entry_SYSCALL_64_after_hwframe+0x49/0xbe [ 37.327183] [ 37.327183] -> #0 (&mdev->req_queue_mutex){+.+.}: [ 37.333497] lock_acquire+0x1ed/0x520 [ 37.337804] __mutex_lock+0x166/0x16f0 [ 37.342194] mutex_lock_nested+0x16/0x20 [ 37.346759] v4l2_release+0x1d7/0x3a0 [ 37.351063] __fput+0x3bc/0xa70 [ 37.354856] delayed_fput+0x55/0x80 [ 37.358994] process_one_work+0xc8b/0x1c40 [ 37.363734] worker_thread+0x17f/0x1390 [ 37.368209] kthread+0x35a/0x440 [ 37.372085] ret_from_fork+0x3a/0x50 [ 37.376297] [ 37.376297] other info that might help us debug this: [ 37.376297] [ 37.384421] Chain exists of: [ 37.384421] &mdev->req_queue_mutex --> (wq_completion)"events" --> (delayed_fput_work).work [ 37.384421] [ 37.397425] Possible unsafe locking scenario: [ 37.397425] [ 37.403463] CPU0 CPU1 [ 37.408116] ---- ---- [ 37.412759] lock((delayed_fput_work).work); [ 37.417246] lock((wq_completion)"events"); [ 37.424151] lock((delayed_fput_work).work); [ 37.431153] lock(&mdev->req_queue_mutex); [ 37.435482] [ 37.435482] *** DEADLOCK *** [ 37.435482] [ 37.441529] 2 locks held by kworker/1:2/2789: [ 37.446004] #0: 000000008de45d29 ((wq_completion)"events"){+.+.}, at: process_one_work+0xb43/0x1c40 [ 37.455303] #1: 0000000027ffdd5c ((delayed_fput_work).work){+.+.}, at: process_one_work+0xb9a/0x1c40 [ 37.464654] [ 37.464654] stack backtrace: [ 37.469134] CPU: 1 PID: 2789 Comm: kworker/1:2 Not tainted 4.20.0-rc1-next-20181109+ #110 [ 37.477427] Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 [ 37.486793] Workqueue: events delayed_fput [ 37.491007] Call Trace: [ 37.493593] dump_stack+0x244/0x39d [ 37.497216] ? dump_stack_print_info.cold.1+0x20/0x20 [ 37.502411] ? vprintk_func+0x85/0x181 [ 37.506323] print_circular_bug.isra.35.cold.56+0x1bd/0x27d [ 37.512020] ? save_trace+0xe0/0x290 [ 37.515717] __lock_acquire+0x3399/0x4c20 [ 37.519862] ? graph_lock+0x270/0x270 [ 37.523652] ? mark_held_locks+0x130/0x130 [ 37.527878] ? __update_load_avg_se+0xae0/0xae0 [ 37.532538] ? lock_unpin_lock+0x4a0/0x4a0 [ 37.536757] ? update_load_avg+0x387/0x2470 [ 37.541063] ? debug_object_activate+0x402/0x600 [ 37.545805] ? attach_entity_load_avg+0x860/0x860 [ 37.550632] ? graph_lock+0x270/0x270 [ 37.554422] ? find_held_lock+0x36/0x1c0 [ 37.558475] ? graph_lock+0x270/0x270 [ 37.562263] ? add_timer+0x624/0x15a0 [ 37.566079] lock_acquire+0x1ed/0x520 [ 37.569866] ? v4l2_release+0x1d7/0x3a0 [ 37.573836] ? lock_release+0xa10/0xa10 [ 37.577806] ? perf_trace_sched_process_exec+0x860/0x860 [ 37.583240] ? print_usage_bug+0xc0/0xc0 [ 37.587290] ? v4l2_release+0x1d7/0x3a0 [ 37.591248] __mutex_lock+0x166/0x16f0 [ 37.595120] ? v4l2_release+0x1d7/0x3a0 [ 37.599078] ? v4l2_release+0x1d7/0x3a0 [ 37.603039] ? mutex_trylock+0x2b0/0x2b0 [ 37.607083] ? __lock_acquire+0x62f/0x4c20 [ 37.611304] ? rcu_read_unlock_special+0x370/0x370 [ 37.616248] ? mark_held_locks+0x130/0x130 [ 37.620466] ? __lock_is_held+0xb5/0x140 [ 37.624511] ? __lock_is_held+0xb5/0x140 [ 37.628557] ? mark_held_locks+0x130/0x130 [ 37.632775] ? set_next_entity+0x485/0xc60 [ 37.636993] ? graph_lock+0x270/0x270 [ 37.640778] ? update_load_avg+0x2470/0x2470 [ 37.645168] ? graph_lock+0x270/0x270 [ 37.648968] ? __sanitizer_cov_trace_const_cmp4+0x16/0x20 [ 37.654502] ? fsnotify+0x50e/0xef0 [ 37.658112] ? __lock_is_held+0xb5/0x140 [ 37.662164] ? __sanitizer_cov_trace_const_cmp8+0x18/0x20 [ 37.667690] ? locks_remove_file+0x3c6/0x5c0 [ 37.672086] ? __sanitizer_cov_trace_const_cmp2+0x18/0x20 [ 37.677617] ? ima_file_free+0x132/0x650 [ 37.681662] ? fsnotify_first_mark+0x350/0x350 [ 37.686228] ? ima_file_check+0x130/0x130 [ 37.690362] ? vivid_remove+0x460/0x460 [ 37.694320] mutex_lock_nested+0x16/0x20 [ 37.698370] ? mutex_lock_nested+0x16/0x20 [ 37.702611] v4l2_release+0x1d7/0x3a0 [ 37.706399] __fput+0x3bc/0xa70 [ 37.709676] ? dev_debug_store+0x140/0x140 [ 37.713893] ? get_max_files+0x20/0x20 [ 37.717777] delayed_fput+0x55/0x80 [ 37.721410] process_one_work+0xc8b/0x1c40 [ 37.725645] ? mark_held_locks+0x130/0x130 [ 37.729882] ? pwq_dec_nr_in_flight+0x4a0/0x4a0 [ 37.734537] ? preempt_notifier_register+0x200/0x200 [ 37.739622] ? __switch_to_asm+0x34/0x70 [ 37.743666] ? __switch_to_asm+0x34/0x70 [ 37.747716] ? __switch_to_asm+0x40/0x70 [ 37.751758] ? __switch_to_asm+0x34/0x70 [ 37.755807] ? __switch_to_asm+0x40/0x70 [ 37.759852] ? __switch_to_asm+0x34/0x70 [ 37.763897] ? __switch_to_asm+0x34/0x70 [ 37.767948] ? __switch_to_asm+0x34/0x70 [ 37.771993] ? __switch_to_asm+0x40/0x70 [ 37.776036] ? __switch_to_asm+0x34/0x70 [ 37.780079] ? __switch_to_asm+0x40/0x70 [ 37.784124] ? __switch_to_asm+0x34/0x70 [ 37.788173] ? set_pf_worker+0x74/0xd0 [ 37.792055] ? __sched_text_start+0x8/0x8 [ 37.796188] ? graph_lock+0x270/0x270 [ 37.799977] ? graph_lock+0x270/0x270 [ 37.803767] ? find_held_lock+0x36/0x1c0 [ 37.807815] ? lock_acquire+0x1ed/0x520 [ 37.811782] ? worker_thread+0x3e0/0x1390 [ 37.815947] ? kasan_check_write+0x14/0x20 [ 37.820164] ? do_raw_spin_lock+0x14f/0x350 [ 37.824467] ? __schedule+0x21d0/0x21d0 [ 37.828435] ? rwlock_bug.part.2+0x90/0x90 [ 37.832662] ? trace_hardirqs_on+0x310/0x310 [ 37.837061] worker_thread+0x17f/0x1390 [ 37.841032] ? preempt_notifier_register+0x200/0x200 [ 37.846119] ? process_one_work+0x1c40/0x1c40 [ 37.850597] ? __schedule+0x8d7/0x21d0 [ 37.854484] ? __sched_text_start+0x8/0x8 [ 37.858616] ? __sched_text_start+0x8/0x8 [ 37.862752] ? __kthread_parkme+0xce/0x1a0 [ 37.866988] ? _raw_spin_unlock_irqrestore+0x82/0xd0 [ 37.872080] ? _raw_spin_unlock_irqrestore+0x82/0xd0 [ 37.877170] ? lockdep_hardirqs_on+0x3bb/0x5b0 [ 37.881738] ? trace_hardirqs_on+0xbd/0x310 [ 37.886046] ? kasan_check_read+0x11/0x20 [ 37.890178] ? __kthread_parkme+0xce/0x1a0 [ 37.894409] ? trace_hardirqs_off_caller+0x300/0x300 [ 37.899503] ? __schedule+0x21d0/0x21d0 [ 37.903465] ? _raw_spin_unlock_irqrestore+0x6d/0xd0 [ 37.908551] ? __sanitizer_cov_trace_const_cmp8+0x18/0x20 executing program [ 37.914128] ? __kthread_parkme+0xfb/0x1a0 [ 37.918350] ? process_one_work+0x1c40/0x1c40 [ 37.922831] kthread+0x35a/0x440 [ 37.926180] ? kthread_stop+0x8f0/0x8f0 [ 37.930138] ret_from_fork+0x3a/0x50 [ 37.934241] kobject: 'regulatory.0' (00000000281e97e8): kobject_uevent_env [ 37.941274] kobject: 'regulatory.0' (00000000281e97e8): fill_kobj_path: path = '/devices/platform/regulatory.0' executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program [ 41.131434] kobject: 'regulatory.0' (00000000281e97e8): kobject_uevent_env [ 41.138484] kobject: 'regulatory.0' (00000000281e97e8): fill_kobj_path: path = '/devices/platform/regulatory.0' executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program