rcu: INFO: rcu_preempt self-detected stall on CPU rcu: 1-...!: (10499 ticks this GP) idle=f26/1/0x4000000000000002 softirq=10910/10910 fqs=0 (t=10501 jiffies g=6633 q=74) rcu: rcu_preempt kthread starved for 10502 jiffies! g6633 f0x0 RCU_GP_WAIT_FQS(5) ->state=0x402 ->cpu=0 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 1 CPU: 1 PID: 8258 Comm: syz-executor.1 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: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:check_kcov_mode kernel/kcov.c:79 [inline] RIP: 0010:__sanitizer_cov_trace_pc+0x22/0x50 kernel/kcov.c:102 Code: 64 02 3b 00 5b 5d c3 cc 48 8b 04 24 65 48 8b 0c 25 c0 1d 02 00 65 8b 15 b8 81 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:ffffc90001ef7ae0 EFLAGS: 00000246 ORIG_RAX: ffffffffffffff13 RAX: ffffffff81487433 RBX: 0000000000000000 RCX: ffff88809a2ae140 RDX: 0000000000000000 RSI: 00000000fffffffc RDI: ffffea00027d2940 RBP: ffffc90001ef7b08 R08: dffffc0000000000 R09: fffffbfff120248a R10: fffffbfff120248a R11: 0000000000000000 R12: dffffc0000000000 R13: dffffc0000000000 R14: 00000000fffffffc R15: ffff8880a86e35e8 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:__fsnotify_parent+0x0/0x270 fs/notify/fsnotify.c:143 Code: f7 e8 34 d2 e4 ff e9 75 fd ff ff 89 f9 80 e1 07 80 c1 03 38 c1 0f 8c a4 fd ff ff e8 3a d2 e4 ff e9 9a fd ff ff 0f 1f 44 00 00 <55> 48 89 e5 41 57 41 56 41 55 41 54 53 48 83 ec 50 41 89 d4 49 89 RSP: 0018:ffffc90001ef7d68 EFLAGS: 00000246 ORIG_RAX: ffffffffffffff13 RAX: 1ffff110146efca3 RBX: ffff8880a377e518 RCX: 0000000000000000 RDX: 0000000000000008 RSI: ffff888092607ce0 RDI: ffff8880a377e510 RBP: ffffc90001ef7de8 R08: ffffffff81bc6194 R09: ffffed1013455d24 R10: ffffed1013455d24 R11: 0000000000000000 R12: dffffc0000000000 R13: 0000000000000008 R14: ffff8880a377e510 R15: ffff88809274c0c0 ____fput+0x15/0x20 fs/file_table.c:313 task_work_run+0x17e/0x1b0 kernel/task_work.c:113 tracehook_notify_resume include/linux/tracehook.h:188 [inline] exit_to_usermode_loop arch/x86/entry/common.c:164 [inline] prepare_exit_to_usermode+0x483/0x5b0 arch/x86/entry/common.c:195 syscall_return_slowpath+0x113/0x4a0 arch/x86/entry/common.c:278 do_syscall_64+0x11f/0x1c0 arch/x86/entry/common.c:304 entry_SYSCALL_64_after_hwframe+0x49/0xbe RIP: 0033:0x45e433 Code: 48 89 ee 48 89 e7 e8 2c 1f fa ff 31 c0 48 89 e2 be 33 89 00 00 89 df e8 bb c0 ff ff 85 c0 78 17 48 63 fb b8 03 00 00 00 0f 05 <8b> 44 24 10 48 83 c4 38 5b 5d c3 66 90 48 c7 c2 d4 ff ff ff 48 63 RSP: 002b:00007ffcf2756240 EFLAGS: 00000246 ORIG_RAX: 0000000000000003 RAX: 0000000000000000 RBX: 0000000000000004 RCX: 000000000045e433 RDX: 00007ffcf2756240 RSI: 0000000000008933 RDI: 0000000000000004 RBP: 00000000004bfc22 R08: 0000000000000009 R09: 00007ffcf2756328 R10: 000000000000000f R11: 0000000000000246 R12: 00000000004bfc22 R13: 0000000000000000 R14: 0000000000000003 R15: 00007ffcf2756328