L1TF CPU bug present and SMT on, data leak possible. See CVE-2018-3646 and https://www.kernel.org/doc/html/latest/admin-guide/hw-vuln/l1tf.html for details. hrtimer: interrupt took 48040 ns debugfs: Directory 'vcpu0' with parent '7238-5' already present! rcu: INFO: rcu_preempt detected stalls on CPUs/tasks: (detected by 1, t=10502 jiffies, g=5365, q=255) rcu: All QSes seen, last rcu_preempt kthread activity 10503 (4294956137-4294945634), jiffies_till_next_fqs=1, root ->qsmask 0x0 syz-executor4 R running task 28016 7337 5746 0x00000800 Call Trace: sched_show_task.cold.102+0x2ee/0x35d kernel/sched/core.c:5954 print_other_cpu_stall kernel/rcu/tree_stall.h:410 [inline] check_cpu_stall kernel/rcu/tree_stall.h:538 [inline] rcu_pending kernel/rcu/tree.c:2827 [inline] rcu_sched_clock_irq.cold.89+0xb2e/0xc5e kernel/rcu/tree.c:2271 update_process_times+0x23/0x50 kernel/time/timer.c:1726 tick_sched_handle+0x77/0x140 kernel/time/tick-sched.c:167 tick_sched_timer+0x43/0x100 kernel/time/tick-sched.c:1310 __run_hrtimer kernel/time/hrtimer.c:1517 [inline] __hrtimer_run_queues+0x332/0xb50 kernel/time/hrtimer.c:1579 hrtimer_interrupt+0x2df/0x760 kernel/time/hrtimer.c:1641 local_apic_timer_interrupt arch/x86/kernel/apic/apic.c:1110 [inline] smp_apic_timer_interrupt+0x16f/0x600 arch/x86/kernel/apic/apic.c:1135 apic_timer_interrupt+0xf/0x20 arch/x86/entry/entry_64.S:829 RIP: 0010:vcpu_enter_guest arch/x86/kvm/x86.c:8257 [inline] RIP: 0010:vcpu_run arch/x86/kvm/x86.c:8354 [inline] RIP: 0010:kvm_arch_vcpu_ioctl_run+0x2bdb/0x5ee0 arch/x86/kvm/x86.c:8561 Code: 0f 61 00 4c 89 e8 48 c1 e8 03 42 80 3c 20 00 0f 85 5f 2b 00 00 48 83 3d 6a 30 46 07 00 0f 84 22 1d 00 00 fb 66 0f 1f 44 00 00 <49> 8d bf 68 01 00 00 48 89 f8 48 c1 e8 03 42 80 3c 20 00 0f 85 4f RSP: 0018:ffff8881d1faf9b0 EFLAGS: 00000282 ORIG_RAX: ffffffffffffff13 RAX: 1ffffffff10a66dd RBX: ffffffff88270220 RCX: 0000000000000006 RDX: 0000000000000000 RSI: 0000000000000008 RDI: ffff8881c077a8d4 RBP: ffff8881d1fafb00 R08: 0000000000000006 R09: fffffbfff13b23ca R10: fffffbfff13b23c9 R11: ffffffff89d91e4f R12: dffffc0000000000 R13: ffffffff885336e8 R14: ffff8881d7ed0138 R15: ffff8881d7ed0100 kvm_vcpu_ioctl+0x507/0xb30 arch/x86/kvm/../../../virt/kvm/kvm_main.c:2847 vfs_ioctl fs/ioctl.c:47 [inline] file_ioctl fs/ioctl.c:545 [inline] do_vfs_ioctl+0x199/0x11b0 fs/ioctl.c:732 ksys_ioctl+0x62/0x90 fs/ioctl.c:749 __do_sys_ioctl fs/ioctl.c:756 [inline] __se_sys_ioctl fs/ioctl.c:754 [inline] __x64_sys_ioctl+0x6e/0xb0 fs/ioctl.c:754 do_syscall_64+0xd0/0x600 arch/x86/entry/common.c:294 entry_SYSCALL_64_after_hwframe+0x49/0xbe RIP: 0033:0x4571e9 Code: fd b4 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 b4 fb ff c3 66 2e 0f 1f 84 00 00 00 00 RSP: 002b:00007f1f60725c78 EFLAGS: 00000246 ORIG_RAX: 0000000000000010 RAX: ffffffffffffffda RBX: 00007f1f607266d4 RCX: 00000000004571e9 RDX: 0000000000000000 RSI: 000000000000ae80 RDI: 0000000000000006 RBP: 00000000009300a0 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000246 R12: 00000000ffffffff R13: 00000000004cf7d0 R14: 00000000004c5a59 R15: 0000000000000000 rcu: rcu_preempt kthread starved for 10537 jiffies! g5365 f0x2 RCU_GP_WAIT_FQS(5) ->state=0x0 ->cpu=1 rcu: RCU grace-period kthread stack dump: rcu_preempt R running task 29368 10 2 0x80004000 Call Trace: context_switch kernel/sched/core.c:3385 [inline] __schedule+0x895/0x1960 kernel/sched/core.c:4081 schedule+0xc3/0x2b0 kernel/sched/core.c:4155 schedule_timeout+0x38b/0xad0 kernel/time/timer.c:1895 rcu_gp_fqs_loop kernel/rcu/tree.c:1661 [inline] rcu_gp_kthread+0x997/0x1820 kernel/rcu/tree.c:1821 kthread+0x334/0x3f0 kernel/kthread.c:255 ret_from_fork+0x3a/0x50 arch/x86/entry/entry_64.S:352