rcu: INFO: rcu_preempt detected stalls on CPUs/tasks: (detected by 0, t=19456 jiffies, g=89033, q=358) rcu: All QSes seen, last rcu_preempt kthread activity 19456 (4295018091-4294998635), jiffies_till_next_fqs=1, root ->qsmask 0x0 syz-executor.2 R running task 26616 24708 9663 0x0000080a Call Trace: sched_show_task kernel/sched/core.c:5755 [inline] sched_show_task.cold+0x2ed/0x34e kernel/sched/core.c:5730 print_other_cpu_stall kernel/rcu/tree_stall.h:410 [inline] check_cpu_stall kernel/rcu/tree_stall.h:536 [inline] rcu_pending kernel/rcu/tree.c:2736 [inline] rcu_sched_clock_irq.cold+0xac8/0xc13 kernel/rcu/tree.c:2183 update_process_times+0x32/0x80 kernel/time/timer.c:1639 tick_sched_handle+0xa2/0x190 kernel/time/tick-sched.c:167 tick_sched_timer+0x53/0x140 kernel/time/tick-sched.c:1296 __run_hrtimer kernel/time/hrtimer.c:1389 [inline] __hrtimer_run_queues+0x364/0xe40 kernel/time/hrtimer.c:1451 hrtimer_interrupt+0x314/0x770 kernel/time/hrtimer.c:1509 local_apic_timer_interrupt arch/x86/kernel/apic/apic.c:1068 [inline] smp_apic_timer_interrupt+0x160/0x610 arch/x86/kernel/apic/apic.c:1093 apic_timer_interrupt+0xf/0x20 arch/x86/entry/entry_64.S:830 RIP: 0010:ffs arch/x86/include/asm/bitops.h:298 [inline] RIP: 0010:__do_softirq+0x227/0x98c kernel/softirq.c:280 Code: c7 c0 20 f3 d2 88 48 c1 e8 03 42 80 3c 30 00 0f 85 b1 06 00 00 48 83 3d 06 f1 72 01 00 0f 84 d6 05 00 00 fb 66 0f 1f 44 00 00 ff ff ff ff 48 c7 45 c8 00 91 c0 88 0f bc 45 d4 83 c0 01 89 45 RSP: 0018:ffff8880ae809f18 EFLAGS: 00000282 ORIG_RAX: ffffffffffffff13 RAX: 1ffffffff11a5e64 RBX: ffff888052616380 RCX: 1ffffffff134b486 RDX: 0000000000000000 RSI: ffffffff8177ed9e RDI: ffffffff876001fc RBP: ffff8880ae809f98 R08: ffff888052616380 R09: 0000000000000000 R10: ffffffff89e45010 R11: 0000000000000001 R12: ffff88805e5ff948 R13: 0000000000000025 R14: dffffc0000000000 R15: 0000000000000000 invoke_softirq kernel/softirq.c:373 [inline] irq_exit+0x19b/0x1e0 kernel/softirq.c:413 exiting_irq arch/x86/include/asm/apic.h:537 [inline] do_IRQ+0x12c/0x200 arch/x86/kernel/irq.c:259 common_interrupt+0xf/0xf arch/x86/entry/entry_64.S:607 RIP: 0010:get_current arch/x86/include/asm/current.h:15 [inline] RIP: 0010:write_comp_data+0x0/0x70 kernel/kcov.c:122 Code: 83 fa 02 75 20 48 8b 88 f8 12 00 00 8b 80 f4 12 00 00 48 8b 11 48 83 c2 01 48 39 d0 76 07 48 89 34 d1 48 89 11 5d c3 0f 1f 00 <65> 4c 8b 04 25 40 fe 01 00 65 8b 05 68 8c 8f 7e a9 00 01 1f 00 75 RSP: 0018:ffff88805e5ff9f8 EFLAGS: 00000246 ORIG_RAX: ffffffffffffffda RAX: dffffc0000000000 RBX: 0000000000000000 RCX: ffffffff810d0203 RDX: 0000000000000000 RSI: 0000000000000000 RDI: 0000000000000007 RBP: ffff88805e5ffa00 R08: ffff888052616380 R09: 0000000000000000 R10: fffffbfff134ae47 R11: ffff888052616380 R12: 0000000000000001 R13: ffff88805cac0880 R14: ffffc9001bdf0dc0 R15: ffff88805cac08b0 vcpu_enter_guest+0x25f3/0x5e90 arch/x86/kvm/x86.c:8092 vcpu_run arch/x86/kvm/x86.c:8151 [inline] kvm_arch_vcpu_ioctl_run+0x464/0x1750 arch/x86/kvm/x86.c:8359 kvm_vcpu_ioctl+0x4dc/0xfd0 arch/x86/kvm/../../../virt/kvm/kvm_main.c:2765 vfs_ioctl fs/ioctl.c:46 [inline] file_ioctl fs/ioctl.c:509 [inline] do_vfs_ioctl+0xdb6/0x13e0 fs/ioctl.c:696 ksys_ioctl+0xab/0xd0 fs/ioctl.c:713 __do_sys_ioctl fs/ioctl.c:720 [inline] __se_sys_ioctl fs/ioctl.c:718 [inline] __x64_sys_ioctl+0x73/0xb0 fs/ioctl.c:718 do_syscall_64+0xfd/0x6a0 arch/x86/entry/common.c:296 entry_SYSCALL_64_after_hwframe+0x49/0xbe RIP: 0033:0x459829 Code: fd b7 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 cb b7 fb ff c3 66 2e 0f 1f 84 00 00 00 00 RSP: 002b:00007f4d41a52c78 EFLAGS: 00000246 ORIG_RAX: 0000000000000010 RAX: ffffffffffffffda RBX: 0000000000000003 RCX: 0000000000459829 RDX: 0000000000000000 RSI: 000000000000ae80 RDI: 0000000000000005 RBP: 000000000075bf20 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000246 R12: 00007f4d41a536d4 R13: 00000000004c2bcf R14: 00000000004d6210 R15: 00000000ffffffff rcu: rcu_preempt kthread starved for 19456 jiffies! g89033 f0x2 RCU_GP_WAIT_FQS(5) ->state=0x0 ->cpu=0 rcu: RCU grace-period kthread stack dump: rcu_preempt R running task 29320 10 2 0x80004000 Call Trace: context_switch kernel/sched/core.c:3254 [inline] __schedule+0x755/0x1580 kernel/sched/core.c:3880 schedule+0xa8/0x270 kernel/sched/core.c:3944 schedule_timeout+0x486/0xc50 kernel/time/timer.c:1807 rcu_gp_fqs_loop kernel/rcu/tree.c:1611 [inline] rcu_gp_kthread+0x9b2/0x18c0 kernel/rcu/tree.c:1768 kthread+0x361/0x430 kernel/kthread.c:255 ret_from_fork+0x24/0x30 arch/x86/entry/entry_64.S:352