rcu: INFO: rcu_preempt self-detected stall on CPU rcu: 1-...!: (10499 ticks this GP) idle=82a/1/0x4000000000000002 softirq=11023/11023 fqs=1 (t=10500 jiffies g=6013 q=29) rcu: rcu_preempt kthread starved for 10498 jiffies! g6013 f0x0 RCU_GP_WAIT_FQS(5) ->state=0x0 ->cpu=0 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 1 CPU: 1 PID: 8068 Comm: blkid Not tainted 5.4.0-syzkaller #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 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:1517 [inline] __hrtimer_run_queues+0x403/0x840 kernel/time/hrtimer.c:1579 hrtimer_interrupt+0x38c/0xda0 kernel/time/hrtimer.c:1641 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:free_thread_stack+0x195/0x590 kernel/fork.c:284 Code: 2e 00 74 08 4c 89 e7 e8 09 a0 69 00 49 8b 1c 24 48 83 c3 08 48 89 d8 48 c1 e8 03 42 80 3c 28 00 74 08 48 89 df e8 eb 9f 69 00 <48> 8b 1b e9 82 ff ff ff e8 5e 2a 2e 00 43 80 3c 2e 00 75 18 eb 1e RSP: 0000:ffffc900025c7bf8 EFLAGS: 00000246 ORIG_RAX: ffffffffffffff13 RAX: 1ffff11014f02551 RBX: ffff8880a7812a88 RCX: ffff88808f20e4c0 RDX: 0000000000000000 RSI: 00000000fffffffc RDI: ffffea0002896f40 RBP: ffffc900025c7c30 R08: dffffc0000000000 R09: fffffbfff1287a8d R10: fffffbfff1287a8d R11: 0000000000000000 R12: ffff8880a7812b20 R13: dffffc0000000000 R14: 1ffff11014f02564 R15: ffff8880942a7428 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:constant_test_bit arch/x86/include/asm/bitops.h:207 [inline] RIP: 0010:test_bit include/asm-generic/bitops-instrumented.h:238 [inline] RIP: 0010:read_pkru arch/x86/include/asm/pgtable.h:131 [inline] RIP: 0010:__pkru_allows_pkey arch/x86/include/asm/pgtable.h:1412 [inline] RIP: 0010:arch_vma_access_permitted arch/x86/include/asm/mmu_context.h:340 [inline] RIP: 0010:access_error arch/x86/mm/fault.c:1186 [inline] RIP: 0010:do_user_addr_fault+0x714/0xaf0 arch/x86/mm/fault.c:1423 Code: 3c 7c 00 48 c1 eb 03 48 b8 00 00 00 00 00 fc ff df 80 3c 03 00 74 0c 48 c7 c7 78 bc 43 89 e8 e3 6d 7c 00 48 8b 1d 54 1b 0e 08 <48> 89 de 48 83 e6 10 31 ff e8 7e fc 40 00 48 83 e3 10 75 0a e8 43 RSP: 0000:ffffc900025c7e48 EFLAGS: 00000246 ORIG_RAX: ffffffffffffff02 RAX: dffffc0000000000 RBX: 0000000000000000 RCX: ffffffff8135a0fd RDX: 0000000000000000 RSI: 0000000000000008 RDI: ffffffff8943bc78 RBP: ffffc900025c7ee0 R08: dffffc0000000000 R09: fffffbfff1287790 R10: fffffbfff1287790 R11: 0000000000000000 R12: 00007fb382c44730 R13: ffff8880985ea5b0 R14: 0000000000000007 R15: ffff888094aba000 __do_page_fault+0xd3/0x1f0 arch/x86/mm/fault.c:1506 do_page_fault+0x99/0xb0 arch/x86/mm/fault.c:1530 page_fault+0x39/0x40 arch/x86/entry/entry_64.S:1203 RIP: 0033:0x7fb382e80789 Code: 00 4d 39 ee 0f 1f 44 00 00 72 28 66 0f 1f 44 00 00 e9 0b fc ff ff 0f 1f 00 4c 89 e0 49 03 46 10 49 83 c6 18 4c 01 e2 4d 39 f5 <48> 89 02 0f 86 ee fb ff ff 41 83 7e 08 08 49 8b 16 74 dc 48 8d 0d RSP: 002b:00007fff56f5aee0 EFLAGS: 00010212 RAX: 00007fb382c485a0 RBX: 00007fb3830939a8 RCX: 00000000000004a8 RDX: 00007fb382c44730 RSI: aaaaaaaaaaaaaaab RDI: 0000000000000000 RBP: 00007fff56f5afc0 R08: 0000000000000001 R09: 0000000000000010 R10: 00007fb3828dfa30 R11: 0000000000000206 R12: 00007fb3828c1000 R13: 00007fb3828df220 R14: 00007fb3828d8278 R15: 00007fb38308b740