Testing all events: OK Running tests again, along with the function tracer Running tests on all trace events: Testing all events: hrtimer: interrupt took 11213232 ns BUG: workqueue lockup - pool cpus=0 node=0 flags=0x0 nice=0 stuck for 11s! Showing busy workqueues and worker pools: workqueue events: flags=0x0 pwq 0: cpus=0 node=0 flags=0x0 nice=0 active=1/256 refcnt=2 pending: vmstat_shepherd BUG: workqueue lockup - pool cpus=0 node=0 flags=0x0 nice=0 stuck for 13s! Showing busy workqueues and worker pools: workqueue events: flags=0x0 pwq 0: cpus=0 node=0 flags=0x0 nice=0 active=1/256 refcnt=2 pending: vmstat_shepherd BUG: workqueue lockup - pool cpus=0 node=0 flags=0x0 nice=0 stuck for 10s! Showing busy workqueues and worker pools: workqueue events: flags=0x0 pwq 0: cpus=0 node=0 flags=0x0 nice=0 active=1/256 refcnt=2 pending: vmstat_shepherd workqueue events_power_efficient: flags=0x82 pwq 2: cpus=0 flags=0x4 nice=0 active=1/256 refcnt=3 pending: neigh_periodic_work BUG: workqueue lockup - pool cpus=0 flags=0x4 nice=0 stuck for 11s! Showing busy workqueues and worker pools: workqueue events: flags=0x0 pwq 0: cpus=0 node=0 flags=0x0 nice=0 active=1/256 refcnt=2 pending: vmstat_shepherd workqueue events_power_efficient: flags=0x82 pwq 2: cpus=0 flags=0x4 nice=0 active=1/256 refcnt=3 pending: neigh_periodic_work BUG: workqueue lockup - pool cpus=0 flags=0x4 nice=0 stuck for 21s! Showing busy workqueues and worker pools: workqueue events: flags=0x0 pwq 0: cpus=0 node=0 flags=0x0 nice=0 active=1/256 refcnt=2 in-flight: 15:vmstat_shepherd workqueue events_power_efficient: flags=0x82 pwq 2: cpus=0 flags=0x4 nice=0 active=1/256 refcnt=3 pending: neigh_periodic_work pool 0: cpus=0 node=0 flags=0x0 nice=0 hung=8s workers=2 idle: 5 BUG: workqueue lockup - pool cpus=0 flags=0x4 nice=0 stuck for 34s! Showing busy workqueues and worker pools: workqueue events: flags=0x0 pwq 0: cpus=0 node=0 flags=0x0 nice=0 active=1/256 refcnt=2 pending: vmstat_shepherd workqueue events_power_efficient: flags=0x82 pwq 2: cpus=0 flags=0x4 nice=0 active=2/256 refcnt=4 pending: neigh_periodic_work, do_cache_clean rcu: INFO: rcu_preempt detected stalls on CPUs/tasks: (detected by 0, t=3752 jiffies, g=2365, q=2) rcu: All QSes seen, last rcu_preempt kthread activity 2599 (4295010564-4295007965), jiffies_till_next_fqs=1, root ->qsmask 0x0 rcu: rcu_preempt kthread starved for 2599 jiffies! g2365 f0x2 RCU_GP_WAIT_FQS(5) ->state=0x0 ->cpu=0 rcu: Unless rcu_preempt kthread gets sufficient CPU time, OOM is now expected behavior. rcu: RCU grace-period kthread stack dump: task:rcu_preempt state:R running task stack: 0 pid: 10 ppid: 2 flags:0x00000428 Call trace: __switch_to+0x148/0x1f0 arch/arm64/kernel/process.c:577 context_switch kernel/sched/core.c:4268 [inline] __schedule+0x2dc/0x9a8 kernel/sched/core.c:5018 preempt_schedule_notrace+0x70/0x1c0 kernel/sched/core.c:5251 __ftrace_ops_list_func kernel/trace/ftrace.c:6955 [inline] ftrace_ops_list_func+0x10c/0x218 kernel/trace/ftrace.c:6976 ftrace_graph_call+0x0/0x4 preempt_count_add+0x8/0x1a0 arch/arm64/include/asm/atomic.h:65 schedule+0x44/0x100 kernel/sched/core.c:5096 schedule_timeout+0x240/0x538 kernel/time/timer.c:1871 rcu_gp_fqs_loop kernel/rcu/tree.c:1946 [inline] rcu_gp_kthread+0x618/0x1bd8 kernel/rcu/tree.c:2119 kthread+0x13c/0x188 kernel/kthread.c:292 ret_from_fork+0x10/0x34 arch/arm64/kernel/entry.S:963 rcu: Stack dump where RCU GP kthread last ran: Task dump for CPU 0: task:khungtaskd state:R running task stack: 0 pid: 23 ppid: 2 flags:0x0000042a Call trace: dump_backtrace+0x0/0x240 arch/arm64/kernel/stacktrace.c:100 show_stack+0x34/0x88 arch/arm64/kernel/stacktrace.c:196 sched_show_task kernel/sched/core.c:6947 [inline] sched_show_task+0x208/0x230 kernel/sched/core.c:6921 dump_cpu_task+0x4c/0x5c kernel/sched/core.c:8985 rcu_check_gp_kthread_starvation+0x240/0x388 kernel/rcu/tree_stall.h:482 print_other_cpu_stall kernel/rcu/tree_stall.h:556 [inline] check_cpu_stall kernel/rcu/tree_stall.h:679 [inline] rcu_pending kernel/rcu/tree.c:3764 [inline] rcu_sched_clock_irq+0x131c/0x1408 kernel/rcu/tree.c:2588 update_process_times+0x6c/0xb8 kernel/time/timer.c:1709 tick_sched_handle.isra.0+0x58/0x88 kernel/time/tick-sched.c:176 tick_sched_timer+0x68/0xe0 kernel/time/tick-sched.c:1328 __run_hrtimer kernel/time/hrtimer.c:1519 [inline] __hrtimer_run_queues+0x288/0x730 kernel/time/hrtimer.c:1583 hrtimer_interrupt+0x114/0x288 kernel/time/hrtimer.c:1645 timer_handler drivers/clocksource/arm_arch_timer.c:647 [inline] arch_timer_handler_virt+0x50/0x70 drivers/clocksource/arm_arch_timer.c:658 handle_percpu_devid_irq+0x104/0x4c0 kernel/irq/chip.c:930 generic_handle_irq_desc include/linux/irqdesc.h:152 [inline] generic_handle_irq+0x54/0x78 kernel/irq/irqdesc.c:650 __handle_domain_irq+0xac/0x130 kernel/irq/irqdesc.c:687 handle_domain_irq include/linux/irqdesc.h:170 [inline] gic_handle_irq+0x70/0x108 drivers/irqchip/irq-gic.c:370 el1_irq+0xc0/0x180 arch/arm64/kernel/entry.S:651 arch_local_irq_enable arch/arm64/include/asm/irqflags.h:37 [inline] __raw_spin_unlock_irq include/linux/spinlock_api_smp.h:168 [inline] _raw_spin_unlock_irq+0x50/0x98 kernel/locking/spinlock.c:199 finish_lock_switch kernel/sched/core.c:4046 [inline] finish_task_switch+0xb4/0x398 kernel/sched/core.c:4146 context_switch kernel/sched/core.c:4271 [inline] __schedule+0x2e0/0x9a8 kernel/sched/core.c:5018 preempt_schedule_irq+0x4c/0xa0 kernel/sched/core.c:5280 arm64_preempt_schedule_irq+0xd0/0x118 arch/arm64/kernel/process.c:725 el1_irq+0xd8/0x180 arch/arm64/kernel/entry.S:664 check_hung_uninterruptible_tasks kernel/hung_task.c:231 [inline] watchdog+0x5d8/0xbe8 kernel/hung_task.c:338 kthread+0x13c/0x188 kernel/kthread.c:292 ret_from_fork+0x10/0x34 arch/arm64/kernel/entry.S:963 ================================ WARNING: inconsistent lock state 5.10.0-rc4-next-20201119-00003-gb88cbc8d31ee #4 Not tainted -------------------------------- inconsistent {IN-HARDIRQ-W} -> {HARDIRQ-ON-W} usage. khungtaskd/23 [HC0[0]:SC0[0]:HE0:SE1] takes: ffffd1f0529f47d8 (rcu_node_0){?.-.}-{2:2}, at: print_other_cpu_stall kernel/rcu/tree_stall.h:516 [inline] ffffd1f0529f47d8 (rcu_node_0){?.-.}-{2:2}, at: check_cpu_stall kernel/rcu/tree_stall.h:679 [inline] ffffd1f0529f47d8 (rcu_node_0){?.-.}-{2:2}, at: rcu_pending kernel/rcu/tree.c:3764 [inline] ffffd1f0529f47d8 (rcu_node_0){?.-.}-{2:2}, at: rcu_sched_clock_irq+0x7c8/0x1408 kernel/rcu/tree.c:2588 {IN-HARDIRQ-W} state was registered at: mark_lock kernel/locking/lockdep.c:4373 [inline] mark_usage kernel/locking/lockdep.c:4301 [inline] __lock_acquire+0xae8/0x1ac8 kernel/locking/lockdep.c:4784 lock_acquire kernel/locking/lockdep.c:5435 [inline] lock_acquire+0x268/0x508 kernel/locking/lockdep.c:5400 __raw_spin_lock_irqsave include/linux/spinlock_api_smp.h:110 [inline] _raw_spin_lock_irqsave+0x78/0x14c kernel/locking/spinlock.c:159 print_other_cpu_stall kernel/rcu/tree_stall.h:516 [inline] check_cpu_stall kernel/rcu/tree_stall.h:679 [inline] rcu_pending kernel/rcu/tree.c:3764 [inline] rcu_sched_clock_irq+0x7c8/0x1408 kernel/rcu/tree.c:2588 update_process_times+0x6c/0xb8 kernel/time/timer.c:1709 tick_sched_handle.isra.0+0x58/0x88 kernel/time/tick-sched.c:176 tick_sched_timer+0x68/0xe0 kernel/time/tick-sched.c:1328 __run_hrtimer kernel/time/hrtimer.c:1519 [inline] __hrtimer_run_queues+0x288/0x730 kernel/time/hrtimer.c:1583 hrtimer_interrupt+0x114/0x288 kernel/time/hrtimer.c:1645 timer_handler drivers/clocksource/arm_arch_timer.c:647 [inline] arch_timer_handler_virt+0x50/0x70 drivers/clocksource/arm_arch_timer.c:658 handle_percpu_devid_irq+0x104/0x4c0 kernel/irq/chip.c:930 generic_handle_irq_desc include/linux/irqdesc.h:152 [inline] generic_handle_irq+0x54/0x78 kernel/irq/irqdesc.c:650 __handle_domain_irq+0xac/0x130 kernel/irq/irqdesc.c:687 handle_domain_irq include/linux/irqdesc.h:170 [inline] gic_handle_irq+0x70/0x108 drivers/irqchip/irq-gic.c:370 el1_irq+0xc0/0x180 arch/arm64/kernel/entry.S:651 arch_local_irq_enable arch/arm64/include/asm/irqflags.h:37 [inline] __raw_spin_unlock_irq include/linux/spinlock_api_smp.h:168 [inline] _raw_spin_unlock_irq+0x50/0x98 kernel/locking/spinlock.c:199 finish_lock_switch kernel/sched/core.c:4046 [inline] finish_task_switch+0xb4/0x398 kernel/sched/core.c:4146 context_switch kernel/sched/core.c:4271 [inline] __schedule+0x2e0/0x9a8 kernel/sched/core.c:5018 preempt_schedule_irq+0x4c/0xa0 kernel/sched/core.c:5280 arm64_preempt_schedule_irq+0xd0/0x118 arch/arm64/kernel/process.c:725 el1_irq+0xd8/0x180 arch/arm64/kernel/entry.S:664 check_hung_uninterruptible_tasks kernel/hung_task.c:231 [inline] watchdog+0x5d8/0xbe8 kernel/hung_task.c:338 kthread+0x13c/0x188 kernel/kthread.c:292 ret_from_fork+0x10/0x34 arch/arm64/kernel/entry.S:963 irq event stamp: 15198 hardirqs last enabled at (15197): [] el1_irq+0xdc/0x180 arch/arm64/kernel/entry.S:685 hardirqs last disabled at (15198): [] el1_irq+0x80/0x180 arch/arm64/kernel/entry.S:648 softirqs last enabled at (14846): [] __do_softirq+0x630/0x6b4 kernel/softirq.c:325 softirqs last disabled at (14843): [] do_softirq_own_stack include/linux/interrupt.h:568 [inline] softirqs last disabled at (14843): [] invoke_softirq kernel/softirq.c:393 [inline] softirqs last disabled at (14843): [] __irq_exit_rcu kernel/softirq.c:423 [inline] softirqs last disabled at (14843): [] irq_exit+0x1cc/0x1e0 kernel/softirq.c:447 other info that might help us debug this: Possible unsafe locking scenario: CPU0 ---- lock(rcu_node_0); lock(rcu_node_0); *** DEADLOCK *** 2 locks held by khungtaskd/23: #0: ffffd1f0529f1420 (rcu_read_lock){....}-{1:2}, at: check_hung_uninterruptible_tasks kernel/hung_task.c:226 [inline] #0: ffffd1f0529f1420 (rcu_read_lock){....}-{1:2}, at: watchdog+0x15c/0xbe8 kernel/hung_task.c:338 #1: ffffd1f0529f47d8 (rcu_node_0){?.-.}-{2:2}, at: print_other_cpu_stall kernel/rcu/tree_stall.h:516 [inline] #1: ffffd1f0529f47d8 (rcu_node_0){?.-.}-{2:2}, at: check_cpu_stall kernel/rcu/tree_stall.h:679 [inline] #1: ffffd1f0529f47d8 (rcu_node_0){?.-.}-{2:2}, at: rcu_pending kernel/rcu/tree.c:3764 [inline] #1: ffffd1f0529f47d8 (rcu_node_0){?.-.}-{2:2}, at: rcu_sched_clock_irq+0x7c8/0x1408 kernel/rcu/tree.c:2588 stack backtrace: CPU: 0 PID: 23 Comm: khungtaskd Not tainted 5.10.0-rc4-next-20201119-00003-gb88cbc8d31ee #4 Hardware name: linux,dummy-virt (DT) Call trace: dump_backtrace+0x0/0x240 arch/arm64/kernel/stacktrace.c:100 show_stack+0x34/0x88 arch/arm64/kernel/stacktrace.c:196 __dump_stack lib/dump_stack.c:79 [inline] dump_stack+0x140/0x1bc lib/dump_stack.c:120 print_usage_bug kernel/locking/lockdep.c:3738 [inline] print_usage_bug+0x2a0/0x2f0 kernel/locking/lockdep.c:3705 valid_state kernel/locking/lockdep.c:3749 [inline] mark_lock_irq kernel/locking/lockdep.c:3952 [inline] mark_lock.part.0+0x438/0x4e8 kernel/locking/lockdep.c:4409 mark_lock kernel/locking/lockdep.c:4007 [inline] mark_held_locks+0x54/0x90 kernel/locking/lockdep.c:4010 __trace_hardirqs_on_caller kernel/locking/lockdep.c:4028 [inline] lockdep_hardirqs_on_prepare+0xe0/0x290 kernel/locking/lockdep.c:4096 trace_hardirqs_on+0x90/0x370 kernel/trace/trace_preemptirq.c:49 el1_irq+0xdc/0x180 arch/arm64/kernel/entry.S:685 arch_local_irq_enable arch/arm64/include/asm/irqflags.h:37 [inline] __raw_spin_unlock_irq include/linux/spinlock_api_smp.h:168 [inline] _raw_spin_unlock_irq+0x50/0x98 kernel/locking/spinlock.c:199 finish_lock_switch kernel/sched/core.c:4046 [inline] finish_task_switch+0xb4/0x398 kernel/sched/core.c:4146 context_switch kernel/sched/core.c:4271 [inline] __schedule+0x2e0/0x9a8 kernel/sched/core.c:5018 preempt_schedule_irq+0x4c/0xa0 kernel/sched/core.c:5280 arm64_preempt_schedule_irq+0xd0/0x118 arch/arm64/kernel/process.c:725 el1_irq+0xd8/0x180 arch/arm64/kernel/entry.S:664 check_hung_uninterruptible_tasks kernel/hung_task.c:231 [inline] watchdog+0x5d8/0xbe8 kernel/hung_task.c:338 kthread+0x13c/0x188 kernel/kthread.c:292 ret_from_fork+0x10/0x34 arch/arm64/kernel/entry.S:963 BUG: scheduling while atomic: khungtaskd/23/0x00000002 INFO: lockdep is turned off. Modules linked in: Preemption disabled at: [] preempt_schedule_irq+0x3c/0xa0 kernel/sched/core.c:5278 CPU: 0 PID: 23 Comm: khungtaskd Not tainted 5.10.0-rc4-next-20201119-00003-gb88cbc8d31ee #4 Hardware name: linux,dummy-virt (DT) Call trace: dump_backtrace+0x0/0x240 arch/arm64/kernel/stacktrace.c:100 show_stack+0x34/0x88 arch/arm64/kernel/stacktrace.c:196 __dump_stack lib/dump_stack.c:79 [inline] dump_stack+0x140/0x1bc lib/dump_stack.c:120 __schedule_bug+0xcc/0xe0 kernel/sched/core.c:4757 schedule_debug kernel/sched/core.c:4784 [inline] __schedule+0x888/0x9a8 kernel/sched/core.c:4912 preempt_schedule_irq+0x4c/0xa0 kernel/sched/core.c:5280 arm64_preempt_schedule_irq+0xd0/0x118 arch/arm64/kernel/process.c:725 el1_irq+0xd8/0x180 arch/arm64/kernel/entry.S:664 check_hung_uninterruptible_tasks kernel/hung_task.c:231 [inline] watchdog+0x5d8/0xbe8 kernel/hung_task.c:338 kthread+0x13c/0x188 kernel/kthread.c:292 ret_from_fork+0x10/0x34 arch/arm64/kernel/entry.S:963