rcu: INFO: rcu_preempt self-detected stall on CPU rcu: 1-...!: (1 GPs behind) idle=83e/1/0x4000000000000004 softirq=95948/95950 fqs=65 rcu: (t=10500 jiffies g=125337 q=1466) rcu: rcu_preempt kthread starved for 10362 jiffies! g125337 f0x0 RCU_GP_WAIT_FQS(5) ->state=0x0 ->cpu=0 rcu: RCU grace-period kthread stack dump: rcu_preempt R running task 29104 10 2 0x80000000 Call Trace: context_switch kernel/sched/core.c:2826 [inline] __schedule+0x866/0x1dc0 kernel/sched/core.c:3515 schedule+0x92/0x1c0 kernel/sched/core.c:3559 schedule_timeout+0x4db/0xfc0 kernel/time/timer.c:1806 rcu_gp_kthread+0xd5c/0x2190 kernel/rcu/tree.c:2202 kthread+0x354/0x420 kernel/kthread.c:246 ret_from_fork+0x24/0x30 arch/x86/entry/entry_64.S:415 NMI backtrace for cpu 1 CPU: 1 PID: 10715 Comm: syz-executor.3 Not tainted 4.19.101-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+0x197/0x210 lib/dump_stack.c:118 nmi_cpu_backtrace.cold+0x63/0xa4 lib/nmi_backtrace.c:101 nmi_trigger_cpumask_backtrace+0x1b0/0x1f8 lib/nmi_backtrace.c:62 arch_trigger_cpumask_backtrace+0x14/0x20 arch/x86/kernel/apic/hw_nmi.c:38 trigger_single_cpu_backtrace include/linux/nmi.h:164 [inline] rcu_dump_cpu_stacks+0x189/0x1d5 kernel/rcu/tree.c:1340 print_cpu_stall kernel/rcu/tree.c:1478 [inline] check_cpu_stall kernel/rcu/tree.c:1550 [inline] __rcu_pending kernel/rcu/tree.c:3293 [inline] rcu_pending kernel/rcu/tree.c:3336 [inline] rcu_check_callbacks.cold+0x5e3/0xd90 kernel/rcu/tree.c:2682 update_process_times+0x32/0x80 kernel/time/timer.c:1638 tick_sched_handle+0xa2/0x190 kernel/time/tick-sched.c:168 tick_sched_timer+0x47/0x130 kernel/time/tick-sched.c:1278 __run_hrtimer kernel/time/hrtimer.c:1401 [inline] __hrtimer_run_queues+0x33b/0xdc0 kernel/time/hrtimer.c:1463 hrtimer_interrupt+0x314/0x770 kernel/time/hrtimer.c:1521 local_apic_timer_interrupt arch/x86/kernel/apic/apic.c:1067 [inline] smp_apic_timer_interrupt+0x111/0x550 arch/x86/kernel/apic/apic.c:1092 apic_timer_interrupt+0xf/0x20 arch/x86/entry/entry_64.S:893 RIP: 0010:debug_lockdep_rcu_enabled kernel/rcu/update.c:253 [inline] RIP: 0010:rcu_read_lock_sched_held+0x3d/0x130 kernel/rcu/update.c:111 Code: 89 c1 48 89 e5 53 83 e0 07 48 c1 e9 03 83 c0 03 0f b6 14 11 38 d0 7c 08 84 d2 0f 85 ae 00 00 00 8b 0d b7 1c 75 08 85 c9 74 3b <48> c7 c3 c0 57 3c 89 48 b8 00 00 00 00 00 fc ff df 48 89 da 48 c1 RSP: 0018:ffff8880ae907d00 EFLAGS: 00000202 ORIG_RAX: ffffffffffffff13 RAX: 0000000000000003 RBX: 0000000000000000 RCX: 0000000000000002 RDX: 0000000000000000 RSI: ffffffff815b53fd RDI: 0000000000000001 RBP: ffff8880ae907d08 R08: ffff88801e0e2080 R09: ffff88801e0e2920 R10: 0000000000000000 R11: 0000000000000000 R12: 0000000000000100 R13: ffff8880ae907db0 R14: 1ffff11015d20fa6 R15: 0000000000000000 trace_timer_expire_exit include/trace/events/timer.h:121 [inline] call_timer_fn+0x632/0x720 kernel/time/timer.c:1327 expire_timers kernel/time/timer.c:1363 [inline] __run_timers kernel/time/timer.c:1684 [inline] __run_timers kernel/time/timer.c:1652 [inline] run_timer_softirq+0x64f/0x16a0 kernel/time/timer.c:1697 __do_softirq+0x25c/0x921 kernel/softirq.c:292 invoke_softirq kernel/softirq.c:372 [inline] irq_exit+0x180/0x1d0 kernel/softirq.c:412 exiting_irq arch/x86/include/asm/apic.h:536 [inline] smp_apic_timer_interrupt+0x13b/0x550 arch/x86/kernel/apic/apic.c:1094 apic_timer_interrupt+0xf/0x20 arch/x86/entry/entry_64.S:893 RIP: 0010:copy_process.part.0+0x182e/0x7a60 kernel/fork.c:1863 Code: df 49 c7 86 20 08 00 00 00 00 00 00 48 89 fa 48 c1 ea 03 0f b6 04 02 84 c0 74 08 3c 03 0f 8e ae 3b 00 00 49 8d be 1c 13 00 00 <48> b8 00 00 00 00 00 fc ff df 41 c7 86 18 13 00 00 00 00 00 00 48 RSP: 0018:ffff888023bcfb90 EFLAGS: 00000246 ORIG_RAX: ffffffffffffff13 RAX: 0000000000000000 RBX: ffff888032a786c0 RCX: ffffc9000c4c1000 RDX: 1ffff1100654f26b RSI: ffffffff813dfa52 RDI: ffff888032a7935c RBP: ffff888023bcfda8 R08: 1ffff1100654f210 R09: 0000000000000000 R10: ffffed100654f216 R11: ffff888032a790b7 R12: ffff888032a790d8 R13: ffff888032a78540 R14: ffff888032a78040 R15: ffff888032a78740 copy_process kernel/fork.c:1694 [inline] _do_fork+0x257/0xfd0 kernel/fork.c:2207 __do_sys_clone kernel/fork.c:2314 [inline] __se_sys_clone kernel/fork.c:2308 [inline] __x64_sys_clone+0xbf/0x150 kernel/fork.c:2308 do_syscall_64+0xfd/0x620 arch/x86/entry/common.c:293 entry_SYSCALL_64_after_hwframe+0x49/0xbe RIP: 0033:0x45b399 Code: ad b6 fb ff c3 66 2e 0f 1f 84 00 00 00 00 00 66 90 48 89 f8 48 89 f7 48 89 d6 48 89 ca 4d 89 c2 4d 89 c8 4c 8b 4c 24 08 0f 05 <48> 3d 01 f0 ff ff 0f 83 7b b6 fb ff c3 66 2e 0f 1f 84 00 00 00 00 RSP: 002b:00007f05f11aec78 EFLAGS: 00000246 ORIG_RAX: 0000000000000038 RAX: ffffffffffffffda RBX: 00007f05f11af6d4 RCX: 000000000045b399 RDX: 9999999999999999 RSI: 0000000000000000 RDI: 0000002102001ffc RBP: 000000000075bf20 R08: ffffffffffffffff R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000246 R12: 00000000ffffffff R13: 0000000000000070 R14: 00000000004c1c24 R15: 000000000075bf2c