[ OK ] Started Getty on tty2. [ OK ] Started Getty on tty1. [ OK ] Started Serial Getty on ttyS0. [ OK ] Reached target Login Prompts. [ OK ] Started OpenBSD Secure Shell server. Debian GNU/Linux 9 syzkaller ttyS0 Warning: Permanently added '10.128.0.185' (ECDSA) to the list of known hosts. executing program executing program syzkaller login: [ 309.741690][ T6512] 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. [ 309.784135][ C0] hrtimer: interrupt took 55807 ns [ 414.775951][ C1] rcu: INFO: rcu_preempt detected stalls on CPUs/tasks: [ 414.783448][ C1] (detected by 1, t=10502 jiffies, g=6477, q=15) [ 414.789868][ C1] rcu: All QSes seen, last rcu_preempt kthread activity 10502 (4294978624-4294968122), jiffies_till_next_fqs=1, root ->qsmask 0x0 [ 414.803233][ C1] rcu: rcu_preempt kthread starved for 10502 jiffies! g6477 f0x2 RCU_GP_WAIT_FQS(5) ->state=0x0 ->cpu=1 [ 414.814344][ C1] rcu: Unless rcu_preempt kthread gets sufficient CPU time, OOM is now expected behavior. [ 414.824310][ C1] rcu: RCU grace-period kthread stack dump: [ 414.830192][ C1] task:rcu_preempt state:R running task stack:26576 pid: 14 ppid: 2 flags:0x00004000 [ 414.841085][ C1] Call Trace: [ 414.844834][ C1] __schedule+0xb72/0x1460 [ 414.849356][ C1] ? __sched_text_start+0x8/0x8 [ 414.854223][ C1] ? mod_timer_pending+0x20/0x20 [ 414.859227][ C1] ? lockdep_softirqs_off+0x420/0x420 [ 414.864650][ C1] schedule+0x14b/0x210 [ 414.868815][ C1] schedule_timeout+0x1b9/0x300 [ 414.873721][ C1] ? console_conditional_schedule+0x40/0x40 [ 414.879710][ C1] ? update_process_times+0x200/0x200 [ 414.887175][ C1] ? prepare_to_swait_event+0x322/0x340 [ 414.893048][ C1] rcu_gp_fqs_loop+0x1fd/0x770 [ 414.898205][ C1] ? rcu_gp_init+0x1160/0x1160 [ 414.903043][ C1] ? finish_swait+0xc2/0x1d0 [ 414.907662][ C1] rcu_gp_kthread+0xa5/0x350 [ 414.912275][ C1] ? rcu_report_qs_rsp+0x1a0/0x1a0 [ 414.917483][ C1] ? _raw_spin_unlock_irqrestore+0xd9/0x130 [ 414.923395][ C1] ? __kthread_parkme+0x166/0x1c0 [ 414.928498][ C1] kthread+0x453/0x480 [ 414.932568][ C1] ? rcu_report_qs_rsp+0x1a0/0x1a0 [ 414.937676][ C1] ? kthread_blkcg+0xd0/0xd0 [ 414.942286][ C1] ret_from_fork+0x1f/0x30 [ 414.946782][ C1] rcu: Stack dump where RCU GP kthread last ran: [ 414.953109][ C1] NMI backtrace for cpu 1 [ 414.957430][ C1] CPU: 1 PID: 6512 Comm: syz-executor558 Not tainted 5.15.0-rc6-syzkaller #0 [ 414.966185][ C1] Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 [ 414.976236][ C1] Call Trace: [ 414.979519][ C1] [ 414.982363][ C1] dump_stack_lvl+0x1dc/0x2d8 [ 414.987115][ C1] ? show_regs_print_info+0x12/0x12 [ 414.992321][ C1] ? log_buf_vmcoreinfo_setup+0x498/0x498 [ 414.998229][ C1] nmi_cpu_backtrace+0x45f/0x490 [ 415.003183][ C1] ? wake_up_klogd+0xbb/0xf0 [ 415.007807][ C1] ? nmi_trigger_cpumask_backtrace+0x280/0x280 [ 415.013963][ C1] ? _printk+0xcf/0x118 [ 415.018129][ C1] ? rcu_check_gp_kthread_starvation+0x1c9/0x270 [ 415.024462][ C1] ? log_buf_vmcoreinfo_setup+0x498/0x498 [ 415.030194][ C1] ? arch_trigger_cpumask_backtrace+0x10/0x10 [ 415.036333][ C1] nmi_trigger_cpumask_backtrace+0x16a/0x280 [ 415.042322][ C1] rcu_check_gp_kthread_starvation+0x1ff/0x270 [ 415.048485][ C1] rcu_sched_clock_irq+0x23d5/0x2bc0 [ 415.053824][ C1] ? timekeeping_advance+0x82f/0xb10 [ 415.059177][ C1] ? rcutree_dead_cpu+0x20/0x20 [ 415.064027][ C1] ? update_wall_time+0xc/0x20 [ 415.068810][ C1] ? hrtimer_run_queues+0x162/0x450 [ 415.074015][ C1] update_process_times+0x197/0x200 [ 415.079221][ C1] tick_sched_timer+0x27d/0x420 [ 415.084681][ C1] __hrtimer_run_queues+0x4cb/0xa60 [ 415.089887][ C1] ? tick_setup_sched_timer+0x2c0/0x2c0 [ 415.095627][ C1] ? hrtimer_interrupt+0x1040/0x1040 [ 415.101001][ C1] ? ktime_get_update_offsets_now+0x449/0x460 [ 415.107090][ C1] hrtimer_interrupt+0x3b3/0x1040 [ 415.112151][ C1] __sysvec_apic_timer_interrupt+0xf9/0x270 [ 415.118059][ C1] sysvec_apic_timer_interrupt+0x8c/0xb0 [ 415.123814][ C1] [ 415.126755][ C1] asm_sysvec_apic_timer_interrupt+0x12/0x20 [ 415.132739][ C1] RIP: 0010:handle_mm_fault+0x1fdf/0x2560 [ 415.138547][ C1] Code: e8 66 b6 13 00 41 89 c6 89 c6 81 e6 00 08 00 00 31 ff e8 f4 47 c6 ff 44 89 f0 25 00 08 00 00 0f 85 0b 02 00 00 e8 d1 43 c6 ff <8b> 84 24 94 00 00 00 85 c0 75 0a e8 c1 43 c6 ff e9 9f 00 00 00 4d [ 415.158191][ C1] RSP: 0018:ffffc900011ee800 EFLAGS: 00000293 [ 415.164265][ C1] RAX: ffffffff81bd6e63 RBX: 1ffff9200023dd34 RCX: ffff88801bd79c80 [ 415.172237][ C1] RDX: 0000000000000000 RSI: 0000000000000002 RDI: 0000000000000000 [ 415.180210][ C1] RBP: ffffc900011eea30 R08: ffffffff81be704f R09: ffffed10173a64a2 [ 415.188529][ C1] R10: ffffed10173a64a2 R11: 0000000000000000 R12: ffff88801bd79c80 [ 415.196618][ C1] R13: dffffc0000000000 R14: 0000000000000002 R15: 0000000000000000 [ 415.204613][ C1] ? do_read_fault+0x3cf/0x650 [ 415.209396][ C1] ? handle_mm_fault+0x1c53/0x2560 [ 415.214635][ C1] ? numa_migrate_prep+0x190/0x190 [ 415.219752][ C1] ? asm_sysvec_apic_timer_interrupt+0x12/0x20 [ 415.225923][ C1] ? __get_user_pages+0x494/0x11f0 [ 415.231044][ C1] ? handle_mm_fault+0x8/0x2560 [ 415.235902][ C1] __get_user_pages+0x4da/0x11f0 [ 415.240855][ C1] ? populate_vma_page_range+0x2a0/0x2a0 [ 415.246482][ C1] ? __down_read_common+0x1b0/0x450 [ 415.251739][ C1] ? up_read_non_owner+0x1c0/0x1c0 [ 415.256878][ C1] get_user_pages_unlocked+0x224/0x8f0 [ 415.262435][ C1] ? get_user_pages_fast_only+0x50/0x50 [ 415.267983][ C1] ? get_user_pages_locked+0x6d0/0x6d0 [ 415.273458][ C1] ? hva_to_pfn_slow+0x91/0x510 [ 415.278411][ C1] hva_to_pfn_slow+0x128/0x510 [ 415.283215][ C1] ? install_new_memslots+0x430/0x430 [ 415.288597][ C1] ? __bpf_trace_rcu_stall_warning+0x10/0x10 [ 415.294666][ C1] ? __print_lock_name+0x1d0/0x1d0 [ 415.299800][ C1] hva_to_pfn+0x233/0xbe0 [ 415.304131][ C1] ? lockdep_hardirqs_on+0x95/0x140 [ 415.309341][ C1] ? __gfn_to_pfn_memslot+0x340/0x340 [ 415.314738][ C1] ? __gfn_to_pfn_memslot+0x22b/0x340 [ 415.320141][ C1] kvm_faultin_pfn+0x366/0x900 [ 415.324997][ C1] ? trace_kvm_mmu_sync_page+0x220/0x220 [ 415.330636][ C1] ? rcu_lock_release+0x9/0x20 [ 415.335401][ C1] ? __lock_acquire+0x2b00/0x2b00 [ 415.340429][ C1] ? trace_fast_page_fault+0xce/0x270 [ 415.345807][ C1] ? kvm_mmu_topup_memory_cache+0x238/0x290 [ 415.351710][ C1] direct_page_fault+0x11f0/0x2b00 [ 415.356909][ C1] ? kvm_tdp_page_fault+0xa0/0xa0 [ 415.361937][ C1] ? lockdep_hardirqs_on_prepare+0x412/0x780 [ 415.367923][ C1] ? mtrr_lookup_next+0xb00/0xb00 [ 415.373062][ C1] ? lockdep_hardirqs_on+0x95/0x140 [ 415.378272][ C1] ? kvm_tdp_page_fault+0x42/0xa0 [ 415.383403][ C1] kvm_mmu_page_fault+0x1a3/0x13d0 [ 415.388533][ C1] ? rcu_read_lock_sched_held+0x89/0x130 [ 415.394343][ C1] ? trace_kvm_page_fault+0x270/0x270 [ 415.399715][ C1] ? asm_sysvec_apic_timer_interrupt+0x12/0x20 [ 415.405871][ C1] ? lockdep_hardirqs_on+0x95/0x140 [ 415.411166][ C1] ? trace_kvm_page_fault+0xe3/0x270 [ 415.416519][ C1] ? handle_ept_violation+0x28c/0x360 [ 415.421900][ C1] vmx_handle_exit+0x26/0x160 [ 415.426598][ C1] vcpu_enter_guest+0x6aa9/0x9650 [ 415.431710][ C1] ? kasan_check_range+0x224/0x2f0 [ 415.436867][ C1] ? validate_chain+0x128/0x8240 [ 415.441818][ C1] ? local_bh_enable+0x20/0x20 [ 415.446582][ C1] ? rcu_lock_release+0x5/0x20 [ 415.451397][ C1] ? __lock_acquire+0x2b00/0x2b00 [ 415.456425][ C1] ? lockdep_hardirqs_on+0x95/0x140 [ 415.461629][ C1] ? reacquire_held_locks+0x620/0x620 [ 415.466998][ C1] ? mark_lock+0x191/0x1e00 [ 415.471523][ C1] ? reacquire_held_locks+0x620/0x620 [ 415.476986][ C1] ? mark_lock+0x191/0x1e00 [ 415.481543][ C1] ? mark_lock+0x191/0x1e00 [ 415.486845][ C1] ? __print_lock_name+0x1d0/0x1d0 [ 415.491962][ C1] ? mark_lock+0x191/0x1e00 [ 415.496483][ C1] ? __print_lock_name+0x1d0/0x1d0 [ 415.501609][ C1] ? mark_lock+0x191/0x1e00 [ 415.506202][ C1] ? __print_lock_name+0x1d0/0x1d0 [ 415.511337][ C1] ? __print_lock_name+0x1d0/0x1d0 [ 415.516459][ C1] ? __print_lock_name+0x1d0/0x1d0 [ 415.521569][ C1] ? __lock_acquire+0x1382/0x2b00 [ 415.526632][ C1] ? lockdep_hardirqs_on_prepare+0x412/0x780 [ 415.532609][ C1] ? print_irqtrace_events+0x220/0x220 [ 415.538077][ C1] ? print_irqtrace_events+0x220/0x220 [ 415.543539][ C1] ? asm_sysvec_apic_timer_interrupt+0x12/0x20 [ 415.549713][ C1] ? lockdep_hardirqs_on+0x95/0x140 [ 415.554921][ C1] ? asm_sysvec_apic_timer_interrupt+0x12/0x20 [ 415.561084][ C1] ? vcpu_run+0x957/0xe50 [ 415.565409][ C1] ? vcpu_run+0x165/0xe50 [ 415.569742][ C1] vcpu_run+0x4d3/0xe50 [ 415.573920][ C1] kvm_arch_vcpu_ioctl_run+0x5c0/0xdb0 [ 415.579387][ C1] kvm_vcpu_ioctl+0x894/0xe20 [ 415.584074][ C1] ? kvm_clear_stat_per_vcpu+0x1d0/0x1d0 [ 415.589708][ C1] ? smack_file_ioctl+0xd1/0x3a0 [ 415.594715][ C1] ? smack_file_ioctl+0x34c/0x3a0 [ 415.599917][ C1] ? smack_file_alloc_security+0xd0/0xd0 [ 415.605558][ C1] ? lockdep_hardirqs_on+0x95/0x140 [ 415.610849][ C1] ? asm_sysvec_apic_timer_interrupt+0x12/0x20 [ 415.617039][ C1] ? bpf_lsm_file_ioctl+0x5/0x10 [ 415.622038][ C1] ? security_file_ioctl+0x9d/0xb0 [ 415.627150][ C1] ? kvm_clear_stat_per_vcpu+0x1d0/0x1d0 [ 415.632784][ C1] __se_sys_ioctl+0xfb/0x170 [ 415.637444][ C1] do_syscall_64+0x44/0xd0 [ 415.641867][ C1] entry_SYSCALL_64_after_hwframe+0x44/0xae [ 415.647845][ C1] RIP: 0033:0x7f5e59994139 [ 415.652267][ C1] Code: 28 00 00 00 75 05 48 83 c4 28 c3 e8 b1 14 00 00 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 73 01 c3 48 c7 c1 c0 ff ff ff f7 d8 64 89 01 48 [ 415.671890][ C1] RSP: 002b:00007ffd4243dee8 EFLAGS: 00000246 ORIG_RAX: 0000000000000010 [ 415.680307][ C1] RAX: ffffffffffffffda RBX: 00000000000f4240 RCX: 00007f5e59994139 [ 415.688455][ C1] RDX: 0000000000000000 RSI: 000000000000ae80 RDI: 0000000000000005 [ 415.696436][ C1] RBP: 0000000000000000 R08: 0000000000000000 R09: 0000000000000000 [ 415.704495][ C1] R10: 0000000000000000 R11: 0000000000000246 R12: 00007f5e59957910 [ 415.712564][ C1] R13: 0000000000000000 R14: 00007ffd4243df20 R15: 00007ffd4243df10