2017/08/23 11:26:29 parsed 1 programs 2017/08/23 11:26:29 executed programs: 0 syzkaller login: [ 45.729313] [ 45.729484] ====================================================== [ 45.729956] WARNING: possible circular locking dependency detected [ 45.731068] 4.13.0-rc6-next-20170823+ #7 Not tainted [ 45.731982] ------------------------------------------------------ [ 45.734258] kworker/0:2/1274 is trying to acquire lock: [ 45.735618] ((shepherd).work){+.+.}, at: [] process_one_work+0xb2c/0x1be0 [ 45.737213] [ 45.737213] but now in release context of a crosslock acquired at the following: [ 45.738562] ((complete)&rcu.completion){+.+.}, at: [] __synchronize_srcu+0x1b5/0x250 [ 45.739989] [ 45.739989] which lock already depends on the new lock. [ 45.739989] [ 45.741255] [ 45.741255] the existing dependency chain (in reverse order) is: [ 45.742450] [ 45.742450] -> #2 ((complete)&rcu.completion){+.+.}: [ 45.743431] __lock_acquire+0x3286/0x4620 [ 45.744173] lock_acquire+0x1d5/0x580 [ 45.744855] wait_for_completion+0xc8/0x770 [ 45.745545] __synchronize_srcu+0x1b5/0x250 [ 45.746302] synchronize_srcu+0x1a3/0x560 [ 45.747060] quarantine_remove_cache+0xd7/0xf0 [ 45.750154] kasan_cache_shrink+0x9/0x10 [ 45.751331] kmem_cache_shrink+0x15/0x30 [ 45.752200] acpi_os_purge_cache+0x15/0x20 [ 45.752866] acpi_purge_cached_objects+0x38/0xc9 [ 45.753842] acpi_initialize_objects+0xc5/0x112 [ 45.754770] acpi_init+0x23c/0x8e6 [ 45.755524] do_one_initcall+0x9e/0x330 [ 45.756698] kernel_init_freeable+0x46e/0x526 [ 45.757928] kernel_init+0x13/0x172 [ 45.758663] ret_from_fork+0x2a/0x40 [ 45.759404] [ 45.759404] -> #1 (cpu_hotplug_lock.rw_sem){++++}: [ 45.760450] __lock_acquire+0x3286/0x4620 [ 45.761199] lock_acquire+0x1d5/0x580 [ 45.761857] cpus_read_lock+0x42/0x90 [ 45.762487] vmstat_shepherd+0x3d/0x1b0 [ 45.763195] process_one_work+0xbfd/0x1be0 [ 45.763914] worker_thread+0x223/0x1860 [ 45.764560] kthread+0x39c/0x470 [ 45.765178] ret_from_fork+0x2a/0x40 [ 45.765765] [ 45.765765] -> #0 ((shepherd).work){+.+.}: [ 45.766645] process_one_work+0xba5/0x1be0 [ 45.767370] worker_thread+0x223/0x1860 [ 45.767999] kthread+0x39c/0x470 [ 45.770707] ret_from_fork+0x2a/0x40 [ 45.771394] 0xffffffffffffffff [ 45.771926] [ 45.771926] other info that might help us debug this: [ 45.771926] [ 45.773166] Chain exists of: [ 45.773166] (shepherd).work --> cpu_hotplug_lock.rw_sem --> (complete)&rcu.completion [ 45.773166] [ 45.775077] Possible unsafe locking scenario by crosslock: [ 45.775077] [ 45.776156] CPU0 CPU1 [ 45.776862] ---- ---- [ 45.777528] lock(cpu_hotplug_lock.rw_sem); [ 45.778219] lock((complete)&rcu.completion); [ 45.779189] lock((shepherd).work); [ 45.780138] unlock((complete)&rcu.completion); [ 45.781225] [ 45.781225] *** DEADLOCK *** [ 45.781225] [ 45.782146] 3 locks held by kworker/0:2/1274: [ 45.782768] #0: ("events_power_efficient"){.+.+}, at: [] process_one_work+0xad4/0x1be0 [ 45.784291] #1: ((&(&sdp->work)->work)){+.+.}, at: [] process_one_work+0xb2c/0x1be0 [ 45.785700] #2: (&x->wait#5){....}, at: [] complete+0x18/0x80 [ 45.786842] [ 45.786842] stack backtrace: [ 45.787556] CPU: 0 PID: 1274 Comm: kworker/0:2 Not tainted 4.13.0-rc6-next-20170823+ #7 [ 45.788758] Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS Bochs 01/01/2011 [ 45.789972] Workqueue: events_power_efficient srcu_invoke_callbacks [ 45.792027] Call Trace: [ 45.792394] dump_stack+0x194/0x257 [ 45.792962] ? arch_local_irq_restore+0x53/0x53 [ 45.793639] print_circular_bug+0x503/0x710 [ 45.794319] ? print_circular_bug_entry+0xb0/0xb0 [ 45.795087] check_prev_add+0x865/0x1520 [ 45.795659] ? graph_lock+0x170/0x170 [ 45.796255] ? check_usage+0xb70/0xb70 [ 45.796797] ? find_held_lock+0x39/0x1d0 [ 45.797442] ? hlock_class+0x140/0x140 [ 45.797984] lock_commit_crosslock+0xe73/0x1d10 [ 45.798717] ? lock_commit_crosslock+0xe73/0x1d10 [ 45.799497] ? perf_trace_lock+0x860/0x860 [ 45.800111] ? check_prev_add+0x1520/0x1520 [ 45.800795] ? lock_acquire+0x1d5/0x580 [ 45.801428] ? complete+0x18/0x80 [ 45.801916] ? lock_release+0xd70/0xd70 [ 45.802558] ? do_raw_spin_trylock+0x190/0x190 [ 45.803233] complete+0x24/0x80 [ 45.803757] wakeme_after_rcu+0xd/0x10 [ 45.804326] srcu_invoke_callbacks+0x280/0x4d0 [ 45.805052] ? srcu_queue_delayed_work_on+0x240/0x240 [ 45.805841] ? __lock_is_held+0xbc/0x140 [ 45.806433] process_one_work+0xbfd/0x1be0 [ 45.807118] ? check_noncircular+0x20/0x20 [ 45.807710] ? pwq_dec_nr_in_flight+0x450/0x450 [ 45.808449] ? finish_task_switch+0x1d3/0x740 [ 45.809184] ? perf_trace_lock_acquire+0xfe/0x900 [ 45.809885] ? __sched_text_start+0x8/0x8 [ 45.810556] ? perf_trace_lock+0x860/0x860 [ 45.811249] ? find_held_lock+0x39/0x1d0 [ 45.811829] ? lock_acquire+0x1d5/0x580 [ 45.812469] ? worker_thread+0x4a3/0x1860 [ 45.813706] ? lock_release+0xd70/0xd70 [ 45.814359] ? do_raw_spin_trylock+0x190/0x190 [ 45.815035] ? retint_kernel+0x10/0x10 [ 45.815655] worker_thread+0x223/0x1860 [ 45.816236] ? process_one_work+0x1be0/0x1be0 [ 45.816932] ? check_noncircular+0x20/0x20 [ 45.817610] ? _raw_spin_unlock_irq+0x27/0x70 [ 45.818255] ? trace_hardirqs_on_caller+0x421/0x5c0 [ 45.819047] ? trace_hardirqs_on+0xd/0x10 [ 45.819697] ? _raw_spin_unlock_irq+0x27/0x70 [ 45.820343] ? finish_task_switch+0x1d3/0x740 [ 45.821054] ? finish_task_switch+0x1aa/0x740 [ 45.821681] ? preempt_notifier_dec+0x20/0x20 [ 45.822393] ? __schedule+0x8f0/0x2070 [ 45.823027] ? try_to_wake_up+0xf9/0x1600 [ 45.823607] ? find_held_lock+0x39/0x1d0 [ 45.824261] ? lock_downgrade+0x990/0x990 [ 45.824845] ? complete+0x18/0x80 [ 45.825401] ? __schedule+0x2070/0x2070 [ 45.825962] ? _raw_spin_unlock_irqrestore+0x31/0xba [ 45.826766] ? trace_hardirqs_on_caller+0x421/0x5c0 [ 45.827580] ? trace_hardirqs_on+0xd/0x10 [ 45.828263] ? __kthread_parkme+0x173/0x240 [ 45.828881] kthread+0x39c/0x470 [ 45.829458] ? process_one_work+0x1be0/0x1be0 [ 45.830094] ? kthread_create_on_node+0x100/0x100 [ 45.830859] ret_from_fork+0x2a/0x40