rcu: INFO: rcu_preempt self-detected stall on CPU rcu: 0-...!: (1 GPs behind) idle=842/1/0x4000000000000002 softirq=12468/12473 fqs=4 (t=10500 jiffies g=7165 q=492) rcu: rcu_preempt kthread starved for 10489 jiffies! g7165 f0x0 RCU_GP_WAIT_FQS(5) ->state=0x0 ->cpu=1 rcu: RCU grace-period kthread stack dump: rcu_preempt R running task 29032 10 2 0x80004000 Call Trace: context_switch kernel/sched/core.c:3385 [inline] __schedule+0x9a0/0xcc0 kernel/sched/core.c:4081 schedule+0x181/0x210 kernel/sched/core.c:4155 schedule_timeout+0x14f/0x240 kernel/time/timer.c:1895 rcu_gp_fqs_loop kernel/rcu/tree.c:1661 [inline] rcu_gp_kthread+0xed8/0x1770 kernel/rcu/tree.c:1821 kthread+0x332/0x350 kernel/kthread.c:255 ret_from_fork+0x24/0x30 arch/x86/entry/entry_64.S:352 NMI backtrace for cpu 0 CPU: 0 PID: 5 Comm: kworker/0:0 Not tainted 5.4.0-syzkaller #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 Workqueue: rcu_gp process_srcu Call Trace: __dump_stack lib/dump_stack.c:77 [inline] dump_stack+0x1fb/0x318 lib/dump_stack.c:118 nmi_cpu_backtrace+0xaf/0x1a0 lib/nmi_backtrace.c:101 nmi_trigger_cpumask_backtrace+0x174/0x290 lib/nmi_backtrace.c:62 arch_trigger_cpumask_backtrace+0x10/0x20 arch/x86/kernel/apic/hw_nmi.c:38 trigger_single_cpu_backtrace include/linux/nmi.h:164 [inline] rcu_dump_cpu_stacks+0x15a/0x220 kernel/rcu/tree_stall.h:254 print_cpu_stall kernel/rcu/tree_stall.h:455 [inline] check_cpu_stall kernel/rcu/tree_stall.h:529 [inline] rcu_pending kernel/rcu/tree.c:2827 [inline] rcu_sched_clock_irq+0xe25/0x1ad0 kernel/rcu/tree.c:2271 update_process_times+0x12d/0x180 kernel/time/timer.c:1726 tick_sched_handle kernel/time/tick-sched.c:167 [inline] tick_sched_timer+0x263/0x420 kernel/time/tick-sched.c:1310 __run_hrtimer kernel/time/hrtimer.c:1514 [inline] __hrtimer_run_queues+0x403/0x840 kernel/time/hrtimer.c:1576 hrtimer_interrupt+0x38c/0xda0 kernel/time/hrtimer.c:1638 local_apic_timer_interrupt arch/x86/kernel/apic/apic.c:1110 [inline] smp_apic_timer_interrupt+0x109/0x280 arch/x86/kernel/apic/apic.c:1135 apic_timer_interrupt+0xf/0x20 arch/x86/entry/entry_64.S:829 RIP: 0010:mod_memcg_page_state+0x16/0x190 include/linux/memcontrol.h:653 Code: 48 83 c4 10 5b 41 5c 41 5d 41 5e 41 5f 5d c3 0f 1f 44 00 00 55 48 89 e5 41 57 41 56 41 54 53 41 89 f6 48 89 fb e8 da 28 2e 00 <48> 83 c3 38 48 89 d8 48 c1 e8 03 49 bc 00 00 00 00 00 fc ff df 42 RSP: 0018:ffffc90000cbf8c8 EFLAGS: 00000293 ORIG_RAX: ffffffffffffff13 RAX: ffffffff81487326 RBX: ffffea00025cef80 RCX: ffff8880a9d9c140 RDX: 0000000000000000 RSI: 00000000fffffffc RDI: ffffea00025cef80 RBP: ffffc90000cbf8e8 R08: 000000000003a768 R09: fffffbfff120248a R10: fffffbfff120248a R11: 0000000000000000 R12: ffff8880a7151520 R13: dffffc0000000000 R14: 00000000fffffffc R15: ffff8880a74ed468 free_thread_stack+0x168/0x590 kernel/fork.c:280 release_task_stack kernel/fork.c:440 [inline] put_task_stack+0xa3/0x130 kernel/fork.c:451 finish_task_switch+0x3f1/0x550 kernel/sched/core.c:3256 context_switch kernel/sched/core.c:3388 [inline] __schedule+0x9a8/0xcc0 kernel/sched/core.c:4081 preempt_schedule_irq+0xc1/0x140 kernel/sched/core.c:4338 retint_kernel+0x1b/0x2b RIP: 0010:delay_tsc+0x96/0xf0 arch/x86/lib/delay.c:68 Code: fb 41 89 c7 0f 01 f9 66 90 49 89 d4 49 c1 e4 20 49 09 c4 eb 29 0f 1f 44 00 00 66 2e 0f 1f 84 00 00 00 00 00 a8 01 75 ca f3 90 01 00 00 00 e8 10 cb 67 f9 e8 1b a3 a8 fb 41 39 c7 75 bb 0f 01 RSP: 0018:ffffc90000cbfb48 EFLAGS: 00000246 ORIG_RAX: ffffffffffffff02 RAX: 0000000080000000 RBX: 0000000000000fc9 RCX: 0000000000000001 RDX: 0000000000000028 RSI: 0000000000000001 RDI: 0000000000000001 RBP: ffffc90000cbfb68 R08: ffffffff8393da27 R09: fffffbfff1455efd R10: fffffbfff1455efd R11: 0000000000000000 R12: 00000028da2c4dff R13: 0000000000000000 R14: 0000000000002ced R15: 0000000000000000 __delay arch/x86/lib/delay.c:161 [inline] __const_udelay+0x5e/0x70 arch/x86/lib/delay.c:175 try_check_zero+0x6e/0x380 kernel/rcu/srcutree.c:705 srcu_advance_state kernel/rcu/srcutree.c:1142 [inline] process_srcu+0x1b7/0xd20 kernel/rcu/srcutree.c:1237 process_one_work+0x7ef/0x10d0 kernel/workqueue.c:2264 worker_thread+0xc01/0x1630 kernel/workqueue.c:2410 kthread+0x332/0x350 kernel/kthread.c:255 ret_from_fork+0x24/0x30 arch/x86/entry/entry_64.S:352