rcu: INFO: rcu_preempt self-detected stall on CPU rcu: 1-...!: (10499 ticks this GP) idle=866/1/0x4000000000000002 softirq=13942/13942 fqs=2 (t=10500 jiffies g=6621 q=67) rcu: rcu_preempt kthread starved for 10496 jiffies! g6621 f0x0 RCU_GP_WAIT_FQS(5) ->state=0x402 ->cpu=0 rcu: RCU grace-period kthread stack dump: rcu_preempt I28984 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: 8469 Comm: syz-executor.0 Not tainted 5.5.0-rc5-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:__sanitizer_cov_trace_pc+0x0/0x50 kernel/kcov.c:183 Code: 66 2e 0f 1f 84 00 00 00 00 00 55 48 89 e5 53 48 89 fb e8 13 00 00 00 48 8b 3d f4 f4 ed 07 48 89 de e8 84 f4 3b 00 5b 5d c3 cc <48> 8b 04 24 65 48 8b 0c 25 c0 1d 02 00 65 8b 15 38 5f 8b 7e f7 c2 RSP: 0018:ffffc90001f97bc8 EFLAGS: 00000246 ORIG_RAX: ffffffffffffff13 RAX: 1ffff11013ca7b21 RBX: ffffea00027eb500 RCX: ffff8880a28d4100 RDX: 0000000000000000 RSI: 00000000fffffffc RDI: ffffea00027eb500 RBP: ffffc90001f97c08 R08: dffffc0000000000 R09: fffffbfff124248a R10: fffffbfff124248a R11: 0000000000000000 R12: ffff88809e53d9a0 R13: dffffc0000000000 R14: 1ffff11013ca7b34 R15: ffff8880937c73f8 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 schedule+0x181/0x210 kernel/sched/core.c:4155 freezable_schedule include/linux/freezer.h:172 [inline] do_nanosleep+0x1d0/0x6c0 kernel/time/hrtimer.c:1874 hrtimer_nanosleep+0x3a6/0x5b0 kernel/time/hrtimer.c:1927 __do_sys_nanosleep kernel/time/hrtimer.c:1961 [inline] __se_sys_nanosleep kernel/time/hrtimer.c:1948 [inline] __x64_sys_nanosleep+0x186/0x1d0 kernel/time/hrtimer.c:1948 do_syscall_64+0xf7/0x1c0 arch/x86/entry/common.c:294 entry_SYSCALL_64_after_hwframe+0x49/0xbe RIP: 0033:0x4593f0 Code: c0 5b 5d c3 66 0f 1f 44 00 00 8b 04 24 48 83 c4 18 5b 5d c3 66 0f 1f 44 00 00 83 3d 41 f5 61 00 00 75 14 b8 23 00 00 00 0f 05 <48> 3d 01 f0 ff ff 0f 83 d4 d1 fb ff c3 48 83 ec 08 e8 ea 46 00 00 RSP: 002b:00007fff21b27938 EFLAGS: 00000246 ORIG_RAX: 0000000000000023 RAX: ffffffffffffffda RBX: 0000000000010d62 RCX: 00000000004593f0 RDX: 0000000000000000 RSI: 0000000000000000 RDI: 00007fff21b27940 RBP: 0000000000000002 R08: 0000000000000001 R09: 00000000024ce940 R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000 R13: 00007fff21b27990 R14: 0000000000010d62 R15: 00007fff21b279a0