rcu: INFO: rcu_preempt self-detected stall on CPU rcu: 0-...!: (10499 ticks this GP) idle=a6a/1/0x4000000000000002 softirq=11881/11881 fqs=14 (t=10501 jiffies g=6181 q=635) rcu: rcu_preempt kthread starved for 10474 jiffies! g6181 f0x0 RCU_GP_WAIT_FQS(5) ->state=0x402 ->cpu=1 rcu: RCU grace-period kthread stack dump: rcu_preempt I29032 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: 8176 Comm: syz-executor.0 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:check_kcov_mode kernel/kcov.c:79 [inline] RIP: 0010:__sanitizer_cov_trace_pc+0x22/0x50 kernel/kcov.c:102 Code: d4 01 3b 00 5b 5d c3 cc 48 8b 04 24 65 48 8b 0c 25 c0 1d 02 00 65 8b 15 38 84 8b 7e f7 c2 00 01 1f 00 75 2c 8b 91 80 13 00 00 <83> fa 02 75 21 48 8b 91 88 13 00 00 48 8b 32 48 8d 7e 01 8b 89 84 RSP: 0018:ffffc90002287890 EFLAGS: 00000246 ORIG_RAX: ffffffffffffff13 RAX: ffffffff81487326 RBX: ffffea00028857c0 RCX: ffff8880929f6540 RDX: 0000000000000000 RSI: 00000000fffffffc RDI: ffffea00028857c0 RBP: ffffc900022878b8 R08: 000000000003a728 R09: fffffbfff120248a R10: fffffbfff120248a R11: 0000000000000000 R12: ffff8880a25f7f20 R13: dffffc0000000000 R14: 00000000fffffffc R15: ffff88809a17b528 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:debug_lockdep_rcu_enabled+0x6/0xe0 kernel/rcu/update.c:250 Code: 7c e3 48 c7 c7 f4 b8 81 89 e8 66 ec 4e 00 eb d5 0f 1f 40 00 55 48 89 e5 e8 a7 b7 00 00 e8 a2 b8 00 00 5d c3 55 48 89 e5 41 57 <41> 56 53 48 c7 c0 5c d5 43 89 48 c1 e8 03 49 bf 00 00 00 00 00 fc RSP: 0000:ffffc90002287b10 EFLAGS: 00000286 ORIG_RAX: ffffffffffffff02 RAX: ffffffff81a3a5d5 RBX: 000000000000002a RCX: ffff8880929f6540 RDX: 0000000000000000 RSI: 00000000000011e6 RDI: ffffffff88bf6ab1 RBP: ffffc90002287b18 R08: ffffffff81a3a66f R09: ffff888097de4390 R10: ffffed1012fbc874 R11: 0000000000000000 R12: 0000000000000000 R13: 0000000000000000 R14: ffff8880929f7918 R15: ffff88806bc2b000 ___might_sleep+0x20/0x5e0 kernel/sched/core.c:6765 process_huge_page mm/memory.c:4582 [inline] clear_huge_page+0x220/0x8a0 mm/memory.c:4643 __do_huge_pmd_anonymous_page+0x21a/0x1010 mm/huge_memory.c:596 do_huge_pmd_anonymous_page+0x91a/0xe50 mm/huge_memory.c:764 create_huge_pmd mm/memory.c:3836 [inline] __handle_mm_fault mm/memory.c:4046 [inline] handle_mm_fault+0x2017/0x2890 mm/memory.c:4112 do_user_addr_fault+0x589/0xaf0 arch/x86/mm/fault.c:1441 __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: 0033:0x4418d1 Code: 2e 0f 1f 84 00 00 00 00 00 48 83 fa 20 48 89 f8 73 77 f6 c2 01 74 0b 0f b6 0e 88 0f 48 ff c6 48 ff c7 f6 c2 02 74 12 0f b7 0e <66> 89 0f 48 83 c6 02 48 83 c7 02 0f 1f 40 00 f6 c2 04 74 0c 8b 0e RSP: 002b:00007ffc82047f68 EFLAGS: 00010202 RAX: 00000000200000c0 RBX: 0000000000000000 RCX: 0000000000002f2e RDX: 0000000000000006 RSI: 0000000000760020 RDI: 00000000200000c0 RBP: 0000000000760000 R08: 0000000000000000 R09: 0000000000000004 R10: 0000000000000075 R11: 0000000000000246 R12: 0000000000000001 R13: 00007ffc82048150 R14: 0000000000760008 R15: 00007ffc82048160