[ OK ] Started Getty on tty3. [ OK ] Started Getty on tty2. [ 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 '10.128.1.10' (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: [ 698.292741] hrtimer: interrupt took 62627 ns [ 803.293733] rcu: INFO: rcu_preempt detected stalls on CPUs/tasks: [ 803.299993] rcu: (detected by 1, t=10502 jiffies, g=4537, q=48) [ 803.306321] rcu: All QSes seen, last rcu_preempt kthread activity 10502 (4295017316-4295006814), jiffies_till_next_fqs=1, root ->qsmask 0x0 [ 803.318969] syz-executor465 R running task 26984 8132 8121 0x00000000 [ 803.326164] Call Trace: [ 803.328745] [ 803.330899] sched_show_task.cold+0x332/0x396 [ 803.335393] ? __se_sys_sched_getattr+0x480/0x480 [ 803.340243] rcu_check_callbacks.cold+0xb37/0xe19 [ 803.345093] update_process_times+0x2a/0x70 [ 803.349407] tick_sched_handle+0x9b/0x180 [ 803.353552] tick_sched_timer+0xfc/0x290 [ 803.357615] __hrtimer_run_queues+0x3f6/0xe60 [ 803.362109] ? tick_nohz_restart_sched_tick+0x310/0x310 [ 803.367478] ? hrtimer_fixup_free+0xa0/0xa0 [ 803.371794] ? kvm_clock_get_cycles+0x14/0x30 [ 803.376280] ? ktime_get_update_offsets_now+0x2ec/0x460 [ 803.381642] hrtimer_interrupt+0x326/0x9e0 [ 803.385890] smp_apic_timer_interrupt+0x10c/0x550 [ 803.390734] apic_timer_interrupt+0xf/0x20 [ 803.394956] [ 803.397361] RIP: 0010:unwind_next_frame+0xf71/0x1400 [ 803.402562] Code: c1 45 84 c0 41 0f 95 c0 45 84 c1 0f 85 b3 02 00 00 83 e0 07 40 38 c6 41 0f 9e c0 40 84 f6 0f 95 c0 41 84 c0 0f 85 9a 02 00 00 <49> 0f bf 77 02 4c 89 f7 48 03 74 24 68 e8 ad ee ff ff 84 c0 0f 85 [ 803.421576] RSP: 0018:ffff888091ea74b8 EFLAGS: 00000246 ORIG_RAX: ffffffffffffff13 [ 803.429372] RAX: 0000000000000000 RBX: 1ffff110123d4ea0 RCX: ffffffff8b99dcf1 [ 803.436637] RDX: ffff888091ea7628 RSI: 0000000000000000 RDI: ffffffff8b99dcee [ 803.443989] RBP: 0000000000000001 R08: 0000000000000001 R09: 0000000000000001 [ 803.451252] R10: ffff888091ea7647 R11: 0000000000074071 R12: ffff888091ea78d0 [ 803.458517] R13: ffff888091ea761d R14: ffff888091ea75e8 R15: ffffffff8b99dcec [ 803.465890] ? unwind_next_frame+0x9fc/0x1400 [ 803.470394] ? kasan_kmalloc+0xeb/0x160 [ 803.474370] ? deref_stack_reg+0x1d0/0x1d0 [ 803.478618] ? __unwind_start+0x5b8/0x960 [ 803.482837] ? unwind_next_frame+0x1400/0x1400 [ 803.487418] ? kasan_kmalloc+0xeb/0x160 [ 803.491388] __save_stack_trace+0xd6/0x190 [ 803.495627] ? kmem_cache_alloc_trace+0x11a/0x380 [ 803.500472] kasan_kmalloc+0xeb/0x160 [ 803.504277] ? update_curr_rt+0x308/0x960 [ 803.508509] ? mark_held_locks+0xf0/0xf0 [ 803.512572] ? __schedule+0x15a9/0x2040 [ 803.516548] ? lock_downgrade+0x720/0x720 [ 803.520773] ? plist_del+0x248/0x450 [ 803.524483] ? _raw_spin_unlock_irq+0x24/0x80 [ 803.528977] ? fs_reclaim_release+0xd0/0x110 [ 803.533380] ? lock_acquire+0x170/0x3c0 [ 803.537355] ? kmem_cache_alloc_trace+0x2be/0x380 [ 803.542192] kmem_cache_alloc_trace+0x11a/0x380 [ 803.546860] tty_open+0x138/0x990 [ 803.550317] ? tty_kopen+0x220/0x220 [ 803.554030] ? chrdev_open+0x7c/0x770 [ 803.557830] ? tty_kopen+0x220/0x220 [ 803.561535] chrdev_open+0x266/0x770 [ 803.565261] ? __register_chrdev+0x400/0x400 [ 803.569679] ? security_file_open+0x30/0x1b0 [ 803.574098] do_dentry_open+0x4aa/0x1160 [ 803.578169] ? __register_chrdev+0x400/0x400 [ 803.582577] ? chown_common+0x550/0x550 [ 803.586747] ? path_openat+0x779/0x2df0 [ 803.590734] path_openat+0x793/0x2df0 [ 803.594548] ? path_lookupat+0x8d0/0x8d0 [ 803.598628] ? mark_held_locks+0xa6/0xf0 [ 803.602688] ? mark_held_locks+0xf0/0xf0 [ 803.606746] ? lockdep_hardirqs_on+0x3a8/0x5c0 [ 803.611329] do_filp_open+0x18c/0x3f0 [ 803.615126] ? may_open_dev+0xf0/0xf0 [ 803.618929] ? lock_downgrade+0x720/0x720 [ 803.623099] ? lock_acquire+0x170/0x3c0 [ 803.627162] ? __alloc_fd+0x34/0x570 [ 803.630879] ? do_raw_spin_unlock+0x171/0x230 [ 803.635368] ? _raw_spin_unlock+0x29/0x40 [ 803.639513] ? __alloc_fd+0x28d/0x570 [ 803.643317] do_sys_open+0x3b3/0x520 [ 803.647025] ? filp_open+0x70/0x70 [ 803.650570] ? entry_SYSCALL_64_after_hwframe+0x3e/0xbe [ 803.655937] ? trace_hardirqs_off_caller+0x6e/0x210 [ 803.661037] ? do_syscall_64+0x21/0x620 [ 803.665011] do_syscall_64+0xf9/0x620 [ 803.668815] entry_SYSCALL_64_after_hwframe+0x49/0xbe [ 803.674000] RIP: 0033:0x7f1bb39c4af9 [ 803.677719] Code: 28 00 00 00 75 05 48 83 c4 28 c3 e8 11 15 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 b8 ff ff ff f7 d8 64 89 01 48 [ 803.696623] RSP: 002b:00007f1bb3976318 EFLAGS: 00000246 ORIG_RAX: 0000000000000101 [ 803.704331] RAX: ffffffffffffffda RBX: 00007f1bb3a4c3e8 RCX: 00007f1bb39c4af9 [ 803.711593] RDX: 0000000000000802 RSI: 0000000020000840 RDI: ffffffffffffff9c [ 803.718866] RBP: 00007f1bb3a4c3e0 R08: 0000000000000000 R09: 0000000000000000 [ 803.726131] R10: 0000000000000000 R11: 0000000000000246 R12: 7974742f7665642f [ 803.733396] R13: 00007ffe87f1f06f R14: 00007f1bb3976400 R15: 0000000000022000 [ 803.740682] rcu: rcu_preempt kthread starved for 10502 jiffies! g4537 f0x2 RCU_GP_WAIT_FQS(5) ->state=0x0 ->cpu=0 [ 803.751158] rcu: RCU grace-period kthread stack dump: [ 803.756339] rcu_preempt R running task 29760 10 2 0x80000000 [ 803.763529] Call Trace: [ 803.766127] __schedule+0x887/0x2040 [ 803.769941] ? io_schedule_timeout+0x140/0x140 [ 803.774524] ? _raw_spin_unlock_irqrestore+0x79/0xe0 [ 803.779638] schedule+0x8d/0x1b0 [ 803.783003] schedule_timeout+0x4cf/0xfe0 [ 803.787247] ? prepare_to_swait_event+0x5b/0x540 [ 803.792179] ? usleep_range+0x170/0x170 [ 803.796150] ? _raw_spin_unlock_irqrestore+0x79/0xe0 [ 803.801255] ? lockdep_hardirqs_on+0x3a8/0x5c0 [ 803.806096] ? collect_expired_timers+0x2a0/0x2a0 [ 803.810937] ? swake_up_all+0x340/0x340 [ 803.814915] rcu_gp_kthread+0xdad/0x21c0 [ 803.819080] ? lock_acquire+0x170/0x3c0 [ 803.823141] ? __rcu_read_unlock+0x160/0x160 [ 803.827554] ? _raw_spin_unlock_irqrestore+0x79/0xe0 [ 803.832656] ? lockdep_hardirqs_on+0x3a8/0x5c0 [ 803.837239] ? _raw_spin_unlock_irqrestore+0x66/0xe0 [ 803.842428] ? __kthread_parkme+0x133/0x1e0 [ 803.846746] ? __rcu_read_unlock+0x160/0x160 [ 803.851160] kthread+0x33f/0x460 [ 803.854521] ? kthread_park+0x180/0x180 [ 803.858516] ret_from_fork+0x24/0x30