INIT: Entering runlevel: 2 [info] Using makefile-style concurrent boot in runlevel 2. [....] Starting enhanced syslogd: rsyslogd[?25l[?1c7[ ok 8[?25h[?0c. [....] Starting periodic command scheduler: cron[?25l[?1c7[ ok 8[?25h[?0c. [....] Starting OpenBSD Secure Shell server: sshd[?25l[?1c7[ ok 8[?25h[?0c. Debian GNU/Linux 7 syzkaller ttyS0 Warning: Permanently added '10.128.10.18' (ECDSA) to the list of known hosts. executing program executing program executing program executing program executing program executing program executing program executing program syzkaller login: [ 411.135032] INFO: rcu_sched self-detected stall on CPU [ 411.140466] 1-....: (124999 ticks this GP) idle=792/1/4611686018427387906 softirq=9920/9920 fqs=31243 [ 411.150042] (t=125000 jiffies g=4830 c=4829 q=20) [ 411.155044] NMI backtrace for cpu 1 [ 411.158667] CPU: 1 PID: 4467 Comm: syzkaller756606 Not tainted 4.16.0+ #3 [ 411.165567] Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 [ 411.174941] Call Trace: [ 411.177500] [ 411.179726] dump_stack+0x1b9/0x294 [ 411.183336] ? dump_stack_print_info.cold.2+0x52/0x52 [ 411.188543] ? lock_release+0xa10/0xa10 [ 411.192509] nmi_cpu_backtrace.cold.4+0x19/0xce [ 411.197200] ? lapic_can_unplug_cpu.cold.26+0x3f/0x3f [ 411.202367] nmi_trigger_cpumask_backtrace+0x151/0x192 [ 411.207622] arch_trigger_cpumask_backtrace+0x14/0x20 [ 411.212823] rcu_dump_cpu_stacks+0x175/0x1c2 [ 411.217228] ? __sanitizer_cov_trace_cmp8+0x18/0x20 [ 411.222226] check_cpu_stall.isra.61.cold.80+0x36c/0x59a [ 411.227656] ? print_other_cpu_stall+0x4a0/0x4a0 [ 411.232392] ? debug_check_no_locks_freed+0x310/0x310 [ 411.237580] ? find_held_lock+0x36/0x1c0 [ 411.241626] ? lock_downgrade+0x8e0/0x8e0 [ 411.245750] ? lock_release+0xa10/0xa10 [ 411.249700] ? graph_lock+0x170/0x170 [ 411.253477] ? graph_lock+0x170/0x170 [ 411.257252] ? graph_lock+0x170/0x170 [ 411.261039] ? __sanitizer_cov_trace_const_cmp4+0x16/0x20 [ 411.266589] ? pvclock_gtod_notify+0x2db/0x3c0 [ 411.271147] ? graph_lock+0x170/0x170 [ 411.274925] ? graph_lock+0x170/0x170 [ 411.278709] ? __lock_is_held+0xb5/0x140 [ 411.282754] rcu_check_callbacks+0x21b/0xad0 [ 411.287141] ? rcu_cpu_stall_reset+0x210/0x210 [ 411.291700] ? trace_hardirqs_off+0xd/0x10 [ 411.295952] ? raise_softirq+0x1b2/0x450 [ 411.299993] ? raise_softirq_irqoff+0x310/0x310 [ 411.304673] ? account_guest_time+0x3d0/0x3d0 [ 411.309147] ? __sanitizer_cov_trace_const_cmp1+0x1a/0x20 [ 411.314687] ? hrtimer_run_queues+0x70/0x300 [ 411.319079] ? run_local_timers+0x168/0x1d0 [ 411.323377] ? timer_clear_idle+0x50/0x50 [ 411.327504] ? account_system_time+0x7f/0xb0 [ 411.331889] ? account_process_tick+0x76/0x240 [ 411.336452] update_process_times+0x2d/0x70 [ 411.340776] tick_sched_handle+0x9f/0x180 [ 411.344903] tick_sched_timer+0x45/0x130 [ 411.348941] __hrtimer_run_queues+0x3e3/0x10a0 [ 411.353504] ? tick_sched_do_timer+0x1a0/0x1a0 [ 411.358068] ? hrtimer_start_range_ns+0xd10/0xd10 [ 411.362927] ? pvclock_read_flags+0x160/0x160 [ 411.367402] ? kvm_clock_read+0x25/0x30 [ 411.371356] ? kvm_clock_read+0x25/0x30 [ 411.375311] ? __sanitizer_cov_trace_cmp4+0x16/0x20 [ 411.380318] ? ktime_get_update_offsets_now+0x3a6/0x570 [ 411.385658] ? do_timer+0x50/0x50 [ 411.389091] ? rcu_nmi_exit+0xd7/0x2b0 [ 411.392997] ? do_raw_spin_lock+0xc1/0x200 [ 411.397220] hrtimer_interrupt+0x286/0x650 [ 411.401482] smp_apic_timer_interrupt+0x15d/0x710 [ 411.406306] ? smp_call_function_single_interrupt+0x650/0x650 [ 411.412167] ? _raw_spin_lock+0x32/0x40 [ 411.416120] ? _raw_spin_unlock+0x22/0x30 [ 411.420282] ? handle_edge_irq+0x330/0x870 [ 411.424516] ? task_prio+0x50/0x50 [ 411.428076] ? trace_hardirqs_off_thunk+0x1a/0x1c [ 411.432901] apic_timer_interrupt+0xf/0x20 [ 411.437109] [ 411.439371] RIP: 0010:echo_char+0x96/0x2e0 [ 411.443589] RSP: 0018:ffff8801b079f6f8 EFLAGS: 00000293 ORIG_RAX: ffffffffffffff13 [ 411.451273] RAX: ffff8801b06ee1c0 RBX: ffffc90001e64000 RCX: ffffffff837ab4a7 [ 411.458527] RDX: 0000000000000000 RSI: ffffffff837ab4b6 RDI: 0000000000000001 [ 411.465773] RBP: ffff8801b079f728 R08: ffff8801b06ee1c0 R09: 0000000000000001 [ 411.473026] R10: ffff8801b06eea20 R11: ffff8801b06ee1c0 R12: 000000000000000f [ 411.480278] R13: ffff8801b02b0dc0 R14: 000000012b1bcc47 R15: 0000000000000c47 [ 411.487533] ? echo_char+0x87/0x2e0 [ 411.491146] ? echo_char+0x96/0x2e0 [ 411.494752] ? echo_char+0x96/0x2e0 [ 411.498361] n_tty_receive_char_special+0x13b3/0x31c0 [ 411.503529] ? down_read+0xaf/0x1b0 [ 411.507134] ? n_tty_receive_buf_common+0xe3/0x2c50 [ 411.512128] ? __down_interruptible+0x6e0/0x6e0 [ 411.516777] ? n_tty_open+0x460/0x460 [ 411.520560] n_tty_receive_buf_common+0x20ca/0x2c50 [ 411.525564] ? n_tty_receive_char_lnext+0x710/0x710 [ 411.530560] ? rcu_note_context_switch+0x710/0x710 [ 411.535480] ? __sanitizer_cov_trace_const_cmp4+0x16/0x20 [ 411.541004] n_tty_receive_buf+0x30/0x40 [ 411.545053] tty_ioctl+0x7e7/0x1870 [ 411.548656] ? tty_vhangup+0x30/0x30 [ 411.552401] ? save_stack+0x43/0xd0 [ 411.556013] ? __kasan_slab_free+0x11a/0x170 [ 411.560405] ? kasan_slab_free+0xe/0x10 [ 411.564367] ? kmem_cache_free+0x86/0x2d0 [ 411.568529] ? putname+0xf2/0x130 [ 411.571978] ? do_sys_open+0x554/0x740 [ 411.575841] ? SyS_open+0x2d/0x40 [ 411.579275] ? do_syscall_64+0x220/0x9d0 [ 411.583316] ? entry_SYSCALL_64_after_hwframe+0x42/0xb7 [ 411.588659] ? kasan_check_read+0x11/0x20 [ 411.592785] ? do_raw_spin_unlock+0x9e/0x2e0 [ 411.597171] ? do_raw_spin_trylock+0x1b0/0x1b0 [ 411.601731] ? kasan_check_write+0x14/0x20 [ 411.605943] ? do_raw_spin_lock+0xc1/0x200 [ 411.610156] ? trace_hardirqs_off+0xd/0x10 [ 411.614368] ? _raw_spin_unlock_irqrestore+0x63/0xc0 [ 411.619494] ? debug_check_no_obj_freed+0x2ff/0x584 [ 411.624494] ? tty_vhangup+0x30/0x30 [ 411.628190] do_vfs_ioctl+0x1cf/0x16a0 [ 411.632055] ? rcu_pm_notify+0xc0/0xc0 [ 411.635922] ? ioctl_preallocate+0x2e0/0x2e0 [ 411.640335] ? fget_raw+0x20/0x20 [ 411.643767] ? putname+0xf2/0x130 [ 411.647201] ? rcu_read_lock_sched_held+0x108/0x120 [ 411.652192] ? kmem_cache_free+0x25c/0x2d0 [ 411.656402] ? putname+0xf7/0x130 [ 411.659900] ? security_file_ioctl+0x94/0xc0 [ 411.664290] ksys_ioctl+0xa9/0xd0 [ 411.667721] SyS_ioctl+0x24/0x30 [ 411.671066] ? ksys_ioctl+0xd0/0xd0 [ 411.674673] do_syscall_64+0x29e/0x9d0 [ 411.678546] ? vmalloc_sync_all+0x30/0x30 [ 411.682671] ? trace_hardirqs_on_thunk+0x1a/0x1c [ 411.687404] ? syscall_return_slowpath+0x5c0/0x5c0 [ 411.692315] ? syscall_return_slowpath+0x30f/0x5c0 [ 411.697223] ? entry_SYSCALL_64_after_hwframe+0x52/0xb7 [ 411.702565] ? trace_hardirqs_off_thunk+0x1a/0x1c [ 411.707389] entry_SYSCALL_64_after_hwframe+0x42/0xb7 [ 411.712554] RIP: 0033:0x4404b9 [ 411.715721] RSP: 002b:00007ffee94bd7f8 EFLAGS: 00000213 ORIG_RAX: 0000000000000010 [ 411.723410] RAX: ffffffffffffffda RBX: 00000000200006c0 RCX: 00000000004404b9 [ 411.730664] RDX: 00000000200000c0 RSI: 0000000000005412 RDI: 0000000000000012 [ 411.737909] RBP: 6d74702f7665642f R08: 000000000000000a R09: 0000000000000000 [ 411.745163] R10: 0000000000000000 R11: 0000000000000213 R12: 0000000000401c30 [ 411.752412] R13: 0000000000401cc0 R14: 0000000000000000 R15: 0000000000000000