INFO: rcu_sched detected stalls on CPUs/tasks: 0-...!: (1 GPs behind) idle=83a/1/4611686018427387904 softirq=9950/9952 fqs=0 (detected by 1, t=125002 jiffies, g=5126, c=5125, q=19) Sending NMI from CPU 1 to CPUs 0: NMI backtrace for cpu 0 CPU: 0 PID: 4593 Comm: syz-executor3 Not tainted 4.15.0-rc4-mm1+ #47 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 RIP: 0010:__sanitizer_cov_trace_pc+0xd/0x50 kernel/kcov.c:94 RSP: 0018:ffff8801d571f328 EFLAGS: 00000046 RAX: ffff8801d7bba080 RBX: ffff8801bc820548 RCX: ffffffff8106382a RDX: 1ffff1003af77411 RSI: ffffc900044be000 RDI: ffff8801d7bba088 RBP: ffff8801d571f328 R08: 0000000000000000 R09: 1ffff1003aae3e40 R10: ffff8801d571f1c8 R11: 0000000000000003 R12: ffff8801d7bba080 R13: ffff8801bc820540 R14: dffffc0000000000 R15: ffff8801d7bba080 FS: 00007f57a0473700(0000) GS:ffff8801db200000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 0000000020fe2000 CR3: 00000001d518c001 CR4: 00000000001626f0 DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000 DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400 Call Trace: kvm_sched_out+0x49/0xa0 arch/x86/kvm/../../../virt/kvm/kvm_main.c:3963 __fire_sched_out_preempt_notifiers kernel/sched/core.c:2550 [inline] fire_sched_out_preempt_notifiers kernel/sched/core.c:2558 [inline] prepare_task_switch kernel/sched/core.c:2594 [inline] context_switch kernel/sched/core.c:2765 [inline] __schedule+0xdc6/0x2060 kernel/sched/core.c:3376 preempt_schedule_common+0x22/0x60 kernel/sched/core.c:3515 _cond_resched+0x1d/0x30 kernel/sched/core.c:4852 slab_pre_alloc_hook mm/slab.h:420 [inline] slab_alloc mm/slab.c:3365 [inline] kmem_cache_alloc+0x2a7/0x760 mm/slab.c:3539 kmem_cache_zalloc include/linux/slab.h:695 [inline] mmu_topup_memory_cache arch/x86/kvm/mmu.c:865 [inline] mmu_topup_memory_caches+0xd2/0x310 arch/x86/kvm/mmu.c:911 kvm_mmu_load+0x21/0xf80 arch/x86/kvm/mmu.c:4635 kvm_mmu_reload arch/x86/kvm/mmu.h:85 [inline] vcpu_enter_guest arch/x86/kvm/x86.c:7016 [inline] vcpu_run arch/x86/kvm/x86.c:7213 [inline] kvm_arch_vcpu_ioctl_run+0x2dc5/0x5cb0 arch/x86/kvm/x86.c:7380 kvm_vcpu_ioctl+0x6f1/0xff0 arch/x86/kvm/../../../virt/kvm/kvm_main.c:2555 vfs_ioctl fs/ioctl.c:46 [inline] do_vfs_ioctl+0x1b1/0x1520 fs/ioctl.c:686 SYSC_ioctl fs/ioctl.c:701 [inline] SyS_ioctl+0x8f/0xc0 fs/ioctl.c:692 entry_SYSCALL_64_fastpath+0x1f/0x96 RIP: 0033:0x452a09 RSP: 002b:00007f57a0472c58 EFLAGS: 00000212 ORIG_RAX: 0000000000000010 RAX: ffffffffffffffda RBX: 000000000071bea0 RCX: 0000000000452a09 RDX: 0000000000000000 RSI: 000000000000ae80 RDI: 0000000000000016 RBP: 0000000000000238 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000212 R12: 00000000006f05e0 R13: 00000000ffffffff R14: 00007f57a04736d4 R15: 0000000000000000 Code: ff 48 8b bd d0 fe ff ff e8 b1 63 37 00 e9 c3 fc ff ff 90 90 90 90 90 90 90 90 90 90 90 90 55 65 48 8b 04 25 c0 bd 01 00 48 89 e5 <65> 8b 15 8c 89 91 7e 81 e2 00 01 1f 00 48 8b 4d 08 75 2b 8b 90 rcu_sched kthread starved for 125002 jiffies! g5126 c5125 f0x0 RCU_GP_WAIT_FQS(3) ->state=0x0 ->cpu=1 rcu_sched R running task 23272 8 2 0x80000000 Call Trace: context_switch kernel/sched/core.c:2800 [inline] __schedule+0x8eb/0x2060 kernel/sched/core.c:3376 schedule+0xf5/0x430 kernel/sched/core.c:3435 schedule_timeout+0x13e/0x6f0 kernel/time/timer.c:1818 rcu_gp_kthread+0x9dd/0x18e0 kernel/rcu/tree.c:2231 kthread+0x33c/0x400 kernel/kthread.c:238 ret_from_fork+0x24/0x30 arch/x86/entry/entry_64.S:524