[ OK ] Reached target Graphical Interface. Starting Update UTMP about System Runlevel Changes... Starting Load/Save RF Kill Switch Status... [ OK ] Started Update UTMP about System Runlevel Changes. [ OK ] Started Load/Save RF Kill Switch Status. Debian GNU/Linux 9 syzkaller ttyS0 Warning: Permanently added '10.128.0.229' (ECDSA) to the list of known hosts. executing program executing program executing program executing program syzkaller login: [ 311.487261] hrtimer: interrupt took 36734 ns executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program [ 439.381329] rcu: INFO: rcu_preempt self-detected stall on CPU [ 439.387402] rcu: 1-...!: (1 GPs behind) idle=25a/1/0x4000000000000002 softirq=14548/14552 fqs=0 [ 439.396777] rcu: (t=10501 jiffies g=4365 q=27) [ 439.401554] rcu: rcu_preempt kthread starved for 10502 jiffies! g4365 f0x0 RCU_GP_WAIT_FQS(5) ->state=0x0 ->cpu=0 [ 439.411947] rcu: RCU grace-period kthread stack dump: [ 439.417166] rcu_preempt R running task 29760 10 2 0x80000000 [ 439.424366] Call Trace: [ 439.426951] __schedule+0x887/0x2040 [ 439.430671] ? io_schedule_timeout+0x140/0x140 [ 439.435249] ? _raw_spin_unlock_irqrestore+0x79/0xe0 [ 439.440345] schedule+0x8d/0x1b0 [ 439.443704] schedule_timeout+0x4cf/0xfe0 [ 439.447845] ? prepare_to_swait_event+0x5b/0x540 [ 439.452598] ? usleep_range+0x170/0x170 [ 439.456567] ? _raw_spin_unlock_irqrestore+0x79/0xe0 [ 439.461689] ? lockdep_hardirqs_on+0x3a8/0x5c0 [ 439.466276] ? collect_expired_timers+0x2a0/0x2a0 [ 439.471112] ? swake_up_all+0x340/0x340 [ 439.475215] rcu_gp_kthread+0xdad/0x21c0 [ 439.479280] ? lock_acquire+0x170/0x3c0 [ 439.483250] ? __rcu_read_unlock+0x160/0x160 [ 439.487674] ? _raw_spin_unlock_irqrestore+0x79/0xe0 [ 439.492773] ? lockdep_hardirqs_on+0x3a8/0x5c0 [ 439.497347] ? _raw_spin_unlock_irqrestore+0x66/0xe0 [ 439.502441] ? __kthread_parkme+0x133/0x1e0 [ 439.506754] ? __rcu_read_unlock+0x160/0x160 [ 439.511171] kthread+0x33f/0x460 [ 439.514528] ? kthread_park+0x180/0x180 [ 439.518498] ret_from_fork+0x24/0x30 [ 439.522214] NMI backtrace for cpu 1 [ 439.525885] CPU: 1 PID: 8183 Comm: syz-executor877 Not tainted 4.19.211-syzkaller #0 [ 439.533755] Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 [ 439.543095] Call Trace: [ 439.545673] [ 439.547820] dump_stack+0x1fc/0x2ef [ 439.551445] nmi_cpu_backtrace.cold+0x63/0xa2 [ 439.555937] ? lapic_can_unplug_cpu+0x80/0x80 [ 439.560428] nmi_trigger_cpumask_backtrace+0x1a6/0x1f0 [ 439.565715] rcu_dump_cpu_stacks+0x15f/0x19c [ 439.570121] rcu_check_callbacks.cold+0x62d/0xe19 [ 439.574961] ? __raise_softirq_irqoff+0x3a/0x1a0 [ 439.579712] ? trace_hardirqs_off+0x64/0x200 [ 439.584130] update_process_times+0x2a/0x70 [ 439.588448] tick_sched_handle+0x9b/0x180 [ 439.592592] tick_sched_timer+0xfc/0x290 [ 439.596660] __hrtimer_run_queues+0x3f6/0xe60 [ 439.601151] ? tick_nohz_restart_sched_tick+0x310/0x310 [ 439.606515] ? hrtimer_fixup_free+0xa0/0xa0 [ 439.610827] ? kvm_clock_get_cycles+0x14/0x30 [ 439.615313] ? ktime_get_update_offsets_now+0x2ec/0x460 [ 439.620682] hrtimer_interrupt+0x326/0x9e0 [ 439.624920] smp_apic_timer_interrupt+0x10c/0x550 [ 439.629762] apic_timer_interrupt+0xf/0x20 [ 439.633983] [ 439.636214] RIP: 0010:lock_acquire+0x1ec/0x3c0 [ 439.641010] Code: 08 00 00 00 00 00 00 48 c1 e8 03 80 3c 10 00 0f 85 b7 01 00 00 48 83 3d 09 2e a6 08 00 0f 84 2a 01 00 00 48 8b 7c 24 08 57 9d <0f> 1f 44 00 00 48 83 c4 18 5b 5d 41 5c 41 5d 41 5e 41 5f c3 65 8b [ 439.659905] RSP: 0018:ffff888094d6f858 EFLAGS: 00000286 ORIG_RAX: ffffffffffffff13 [ 439.667604] RAX: 1ffffffff13e3051 RBX: ffff888094ce6680 RCX: 00000000000017d0 [ 439.674868] RDX: dffffc0000000000 RSI: 000000000eae4bec RDI: 0000000000000286 [ 439.682130] RBP: ffffffff89ff4d00 R08: ffffffff8cd233c0 R09: 0000000000000000 [ 439.689389] R10: ffff888094ce6f08 R11: 0000000000000000 R12: 0000000000000000 [ 439.696651] R13: 0000000000000000 R14: 0000000000000000 R15: 0000000000000001 [ 439.703939] fs_reclaim_acquire+0x105/0x130 [ 439.708254] ? fs_reclaim_acquire+0xe5/0x130 [ 439.712663] kmem_cache_alloc_trace+0x28/0x380 [ 439.717240] tty_open+0x138/0x990 [ 439.720695] ? tty_kopen+0x220/0x220 [ 439.724399] ? chrdev_open+0x7c/0x770 [ 439.728201] ? tty_kopen+0x220/0x220 [ 439.731905] chrdev_open+0x266/0x770 [ 439.735613] ? lockref_get+0x11/0x50 [ 439.739323] ? __register_chrdev+0x400/0x400 [ 439.743730] ? check_preemption_disabled+0x41/0x280 [ 439.748751] do_dentry_open+0x4aa/0x1160 [ 439.752898] ? __register_chrdev+0x400/0x400 [ 439.757302] ? inode_permission.part.0+0x10c/0x450 [ 439.762222] ? chown_common+0x550/0x550 [ 439.766196] ? inode_permission+0x3d/0x140 [ 439.770432] path_openat+0x793/0x2df0 [ 439.774234] ? path_lookupat+0x8d0/0x8d0 [ 439.778291] ? mark_held_locks+0xa6/0xf0 [ 439.782348] ? mark_held_locks+0xf0/0xf0 [ 439.786411] do_filp_open+0x18c/0x3f0 [ 439.790202] ? may_open_dev+0xf0/0xf0 [ 439.794006] ? lock_downgrade+0x720/0x720 [ 439.798161] ? do_raw_spin_unlock+0x171/0x230 [ 439.802653] ? _raw_spin_unlock+0x29/0x40 [ 439.806792] ? __alloc_fd+0x28d/0x570 [ 439.810768] do_sys_open+0x3b3/0x520 [ 439.814478] ? filp_open+0x70/0x70 [ 439.818016] ? entry_SYSCALL_64_after_hwframe+0x3e/0xbe [ 439.823375] ? trace_hardirqs_off_caller+0x6e/0x210 [ 439.828382] ? do_syscall_64+0x21/0x620 [ 439.832373] do_syscall_64+0xf9/0x620 [ 439.836172] entry_SYSCALL_64_after_hwframe+0x49/0xbe [ 439.841356] RIP: 0033:0x7f9856808af9 [ 439.845076] 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 [ 439.863996] RSP: 002b:00007f98567ba318 EFLAGS: 00000246 ORIG_RAX: 0000000000000101 [ 439.871699] RAX: ffffffffffffffda RBX: 00007f98568903e8 RCX: 00007f9856808af9 [ 439.878962] RDX: 0000000000000802 RSI: 0000000020000840 RDI: ffffffffffffff9c [ 439.886222] RBP: 00007f98568903e0 R08: 0000000000000000 R09: 0000000000000000 [ 439.893479] R10: 0000000000000000 R11: 0000000000000246 R12: 7974742f7665642f [ 439.900824] R13: 00007ffe867ea86f R14: 00007f98567ba400 R15: 0000000000022000