BUG: workqueue lockup - pool cpus=1 node=0 flags=0x0 nice=0 stuck for 91s!
Showing busy workqueues and worker pools:
workqueue events: flags=0x0
  pwq 2: cpus=1 node=0 flags=0x0 nice=0 active=2/256 refcnt=3
    in-flight: 7435:linkwatch_event
    pending: free_work
  pwq 0: cpus=0 node=0 flags=0x0 nice=0 active=12/256 refcnt=13
    pending: kfree_rcu_monitor, nsim_dev_trap_report_work, nsim_dev_trap_report_work, nsim_dev_trap_report_work, psi_avgs_work, ovs_dp_masks_rebalance, ovs_dp_masks_rebalance, ovs_dp_masks_rebalance, ovs_dp_masks_rebalance, ovs_dp_masks_rebalance, vmstat_shepherd, cache_reap
workqueue events_long: flags=0x0
  pwq 0: cpus=0 node=0 flags=0x0 nice=0 active=4/256 refcnt=5
    pending: defense_work_handler, defense_work_handler, defense_work_handler, defense_work_handler
rcu: INFO: rcu_preempt self-detected stall on CPU
rcu: 	0-...!: (1 GPs behind) idle=432/0/0x3 softirq=8755/8773 fqs=0 
	(t=14713 jiffies g=3409 q=647)
rcu: rcu_preempt kthread starved for 14713 jiffies! g3409 f0x0 RCU_GP_WAIT_FQS(5) ->state=0x402 ->cpu=1
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:I stack:14328 pid:   10 ppid:     2 flags:0x00004000
Call Trace:
 context_switch kernel/sched/core.c:3779 [inline]
 __schedule+0x404/0x890 kernel/sched/core.c:4528
 schedule+0x38/0xe0 kernel/sched/core.c:4606
 schedule_timeout+0x1be/0x2e0 kernel/time/timer.c:1871
 rcu_gp_fqs_loop kernel/rcu/tree.c:1925 [inline]
 rcu_gp_kthread+0x707/0xc60 kernel/rcu/tree.c:2099
 kthread+0x145/0x170 kernel/kthread.c:292
 ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:296
NMI backtrace for cpu 0
CPU: 0 PID: 0 Comm: swapper/0 Not tainted 5.10.0-rc7-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
Call Trace:
 <IRQ>
 __dump_stack lib/dump_stack.c:77 [inline]
 dump_stack+0xa3/0xc8 lib/dump_stack.c:118
 nmi_cpu_backtrace.cold.8+0x53/0x6d lib/nmi_backtrace.c:105
 nmi_trigger_cpumask_backtrace+0xd5/0xf0 lib/nmi_backtrace.c:62
 trigger_single_cpu_backtrace include/linux/nmi.h:164 [inline]
 rcu_dump_cpu_stacks+0xa2/0xce kernel/rcu/tree_stall.h:331
 print_cpu_stall kernel/rcu/tree_stall.h:563 [inline]
 check_cpu_stall kernel/rcu/tree_stall.h:637 [inline]
 rcu_pending kernel/rcu/tree.c:3694 [inline]
 rcu_sched_clock_irq.cold.95+0x61/0x5d5 kernel/rcu/tree.c:2567
 update_process_times+0x50/0x80 kernel/time/timer.c:1709
 tick_sched_handle.isra.24+0x1a/0x50 kernel/time/tick-sched.c:176
 tick_sched_timer+0x6c/0x80 kernel/time/tick-sched.c:1328
 __run_hrtimer kernel/time/hrtimer.c:1519 [inline]
 __hrtimer_run_queues+0x1e3/0x4f0 kernel/time/hrtimer.c:1583
 hrtimer_interrupt+0xf9/0x210 kernel/time/hrtimer.c:1645
 local_apic_timer_interrupt arch/x86/kernel/apic/apic.c:1080 [inline]
 __sysvec_apic_timer_interrupt+0x8e/0x290 arch/x86/kernel/apic/apic.c:1097
 run_sysvec_on_irqstack_cond arch/x86/include/asm/irq_stack.h:91 [inline]
 sysvec_apic_timer_interrupt+0x52/0xf0 arch/x86/kernel/apic/apic.c:1091
 asm_sysvec_apic_timer_interrupt+0x12/0x20 arch/x86/include/asm/idtentry.h:631
RIP: 0010:arch_local_irq_restore arch/x86/include/asm/paravirt.h:653 [inline]
RIP: 0010:__raw_spin_unlock_irqrestore include/linux/spinlock_api_smp.h:160 [inline]
RIP: 0010:_raw_spin_unlock_irqrestore+0x32/0x70 kernel/locking/spinlock.c:191
Code: 53 48 89 f3 48 8b 74 24 10 e8 0a 74 15 fe 48 89 ef e8 62 b8 15 fe f6 c7 02 75 2c 48 83 3d 0d ed 1e 01 00 74 31 48 89 df 57 9d <0f> 1f 44 00 00 bf 01 00 00 00 e8 0f 17 12 fe 65 8b 05 28 a8 f3 7c
RSP: 0018:ffffc90000003e08 EFLAGS: 00000282
RAX: 0000000000046b1a RBX: 0000000000000282 RCX: 0000000000000002
RDX: 0000000000000000 RSI: ffffffff83f3143b RDI: 0000000000000282
RBP: ffff888237c2d380 R08: 0000000000000001 R09: 0000000000000001
R10: ffffc90000003c10 R11: ffffc90000003c08 R12: 0000000000000282
R13: ffffffff83eac151 R14: 00000000ffffd5da R15: ffff888237c31e00
 show_workqueue_state.cold.58+0xa4/0x2da kernel/workqueue.c:4788
 wq_watchdog_timer_fn+0x224/0x230 kernel/workqueue.c:5801
 call_timer_fn+0xa5/0x300 kernel/time/timer.c:1410
 expire_timers kernel/time/timer.c:1455 [inline]
 __run_timers kernel/time/timer.c:1747 [inline]
 run_timer_softirq+0x4d2/0x570 kernel/time/timer.c:1762
 __do_softirq+0xe9/0x52f kernel/softirq.c:298
 asm_call_irq_on_stack+0xf/0x20
 </IRQ>
 __run_on_irqstack arch/x86/include/asm/irq_stack.h:26 [inline]
 run_on_irqstack_cond arch/x86/include/asm/irq_stack.h:77 [inline]
 do_softirq_own_stack+0x7c/0xa0 arch/x86/kernel/irq_64.c:77
 invoke_softirq kernel/softirq.c:393 [inline]
 __irq_exit_rcu kernel/softirq.c:423 [inline]
 irq_exit_rcu+0xea/0x110 kernel/softirq.c:435
 sysvec_apic_timer_interrupt+0x57/0xf0 arch/x86/kernel/apic/apic.c:1091
 asm_sysvec_apic_timer_interrupt+0x12/0x20 arch/x86/include/asm/idtentry.h:631
RIP: 0010:native_safe_halt+0xe/0x10 arch/x86/include/asm/irqflags.h:61
Code: 5b c3 65 48 8b 04 25 c0 7e 01 00 f0 80 48 02 20 48 8b 00 a8 08 75 c3 e9 7c ff ff ff e9 07 00 00 00 0f 00 2d 0c 45 54 00 fb f4 <c3> 90 e9 07 00 00 00 0f 00 2d fc 44 54 00 f4 c3 cc cc e8 cb 07 ff
RSP: 0018:ffffffff84203e38 EFLAGS: 00000286
RAX: 0000000000045261 RBX: ffff888103fd5c00 RCX: 00000000ffffffff
RDX: 0000000000000000 RSI: ffffffff83f3143b RDI: ffffffff83f6e406
RBP: ffffffff84529b80 R08: 0000000000000001 R09: 0000000000000001
R10: ffff888237c2c404 R11: ffff888237c2c3e4 R12: 0000000000000001
R13: ffff888100ca5864 R14: 0000000000000001 R15: 0000000000000000
 arch_safe_halt arch/x86/include/asm/paravirt.h:150 [inline]
 acpi_safe_halt drivers/acpi/processor_idle.c:111 [inline]
 acpi_idle_do_entry+0x50/0x90 drivers/acpi/processor_idle.c:517
 acpi_idle_enter+0xa0/0xf0 drivers/acpi/processor_idle.c:648
 cpuidle_enter_state+0x94/0x520 drivers/cpuidle/cpuidle.c:237
 cpuidle_enter+0x24/0x40 drivers/cpuidle/cpuidle.c:351
 call_cpuidle kernel/sched/idle.c:158 [inline]
 cpuidle_idle_call kernel/sched/idle.c:239 [inline]
 do_idle+0x2dc/0x350 kernel/sched/idle.c:299
 cpu_startup_entry+0x14/0x20 kernel/sched/idle.c:395
 start_kernel+0x4eb/0x50a init/main.c:1061
 secondary_startup_64_no_verify+0xb0/0xbb