[ OK ] Reached target Graphical Interface. Starting Update UTMP about System Runlevel Changes... Starting Load/Save RF Kill Switch Status... [ OK ] Started Load/Save RF Kill Switch Status. [ OK ] Started Update UTMP about System Runlevel Changes. Debian GNU/Linux 9 syzkaller ttyS0 Warning: Permanently added '10.128.15.193' (ECDSA) to the list of known hosts. executing program executing program executing program executing program executing program executing program executing program syzkaller login: [ 504.712959] hrtimer: interrupt took 46428 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 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 executing program executing program executing program executing program executing program executing program executing program [ 610.069909] rcu: INFO: rcu_preempt detected stalls on CPUs/tasks: [ 610.076213] rcu: (detected by 0, t=10502 jiffies, g=5245, q=53) [ 610.082383] rcu: All QSes seen, last rcu_preempt kthread activity 10503 (4294998001-4294987498), jiffies_till_next_fqs=1, root ->qsmask 0x0 [ 610.097742] syz-executor554 R running task 26984 8175 8095 0x00000000 [ 610.104954] Call Trace: [ 610.107550] [ 610.109709] sched_show_task.cold+0x332/0x396 [ 610.114213] ? __se_sys_sched_getattr+0x480/0x480 [ 610.119355] rcu_check_callbacks.cold+0xb37/0xe19 [ 610.124331] update_process_times+0x2a/0x70 [ 610.128670] tick_sched_handle+0x9b/0x180 [ 610.132933] tick_sched_timer+0xfc/0x290 [ 610.137020] __hrtimer_run_queues+0x3f6/0xe60 [ 610.141547] ? tick_nohz_restart_sched_tick+0x310/0x310 [ 610.146929] ? hrtimer_fixup_init+0xa0/0xa0 [ 610.151371] ? kvm_clock_get_cycles+0x14/0x30 [ 610.155975] ? ktime_get_update_offsets_now+0x2ec/0x460 [ 610.161368] hrtimer_interrupt+0x326/0x9e0 [ 610.165638] smp_apic_timer_interrupt+0x10c/0x550 [ 610.170502] apic_timer_interrupt+0xf/0x20 [ 610.174738] [ 610.176986] RIP: 0010:__sanitizer_cov_trace_pc+0x4/0x50 [ 610.182424] Code: e8 c1 c1 35 00 e9 ab fe ff ff 4c 89 ef e8 b4 c1 35 00 e9 23 fe ff ff 90 90 90 90 90 90 90 90 90 90 90 90 90 90 90 48 8b 34 24 <65> 48 8b 04 25 80 df 01 00 65 8b 15 7c 84 9f 7e 81 e2 00 01 1f 00 [ 610.201338] RSP: 0018:ffff888094cb7858 EFLAGS: 00000293 ORIG_RAX: ffffffffffffff13 [ 610.209053] RAX: ffff8880b0144680 RBX: ffffffff8a45d1e0 RCX: 0000000000000001 [ 610.216414] RDX: 0000000000000000 RSI: ffffffff8375be65 RDI: ffffffff88b3c180 [ 610.223703] RBP: ffffffff88b3c180 R08: 00000000006000c0 R09: 0000000000000003 [ 610.230987] R10: 00000000b0f57453 R11: 000000001c8f048c R12: ffff8880a296ce00 [ 610.238822] R13: ffffffff88b3c140 R14: 0000000000000020 R15: ffffffff83b78d78 [ 610.246114] ? tty_open+0x138/0x990 [ 610.249767] ? check_preemption_disabled+0x15/0x280 [ 610.254901] check_preemption_disabled+0x15/0x280 [ 610.259751] ? tty_open+0x138/0x990 [ 610.263385] rcu_is_watching+0x12/0xc0 [ 610.267293] rcu_read_lock_sched_held+0xc6/0x1d0 [ 610.272065] kmem_cache_alloc_trace+0x323/0x380 [ 610.276752] tty_open+0x138/0x990 [ 610.280215] ? tty_kopen+0x220/0x220 [ 610.283937] ? tty_kopen+0x220/0x220 [ 610.287675] chrdev_open+0x266/0x770 [ 610.291392] ? __register_chrdev+0x400/0x400 [ 610.295845] do_dentry_open+0x4aa/0x1160 [ 610.299912] ? __register_chrdev+0x400/0x400 [ 610.304335] ? inode_permission.part.0+0x10c/0x450 [ 610.309274] ? chown_common+0x550/0x550 [ 610.313263] ? inode_permission+0x3d/0x140 [ 610.317533] path_openat+0x793/0x2df0 [ 610.321355] ? path_lookupat+0x8d0/0x8d0 [ 610.325443] ? retint_kernel+0x2d/0x2d [ 610.329357] do_filp_open+0x18c/0x3f0 [ 610.333167] ? may_open_dev+0xf0/0xf0 [ 610.337003] ? lock_downgrade+0x720/0x720 [ 610.341161] ? lock_acquire+0x170/0x3c0 [ 610.345145] ? __alloc_fd+0x34/0x570 [ 610.348869] ? do_raw_spin_unlock+0x171/0x230 [ 610.353383] ? _raw_spin_unlock+0x29/0x40 [ 610.357535] ? __alloc_fd+0x28d/0x570 [ 610.361348] do_sys_open+0x3b3/0x520 [ 610.365066] ? filp_open+0x70/0x70 [ 610.368701] ? entry_SYSCALL_64_after_hwframe+0x3e/0xbe [ 610.374095] ? trace_hardirqs_off_caller+0x6e/0x210 [ 610.379123] ? do_syscall_64+0x21/0x620 [ 610.383114] do_syscall_64+0xf9/0x620 [ 610.386928] entry_SYSCALL_64_after_hwframe+0x49/0xbe [ 610.392122] RIP: 0033:0x445a39 [ 610.395336] 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 [ 610.414246] RSP: 002b:00007f2430ff3308 EFLAGS: 00000246 ORIG_RAX: 0000000000000101 [ 610.421962] RAX: ffffffffffffffda RBX: 00000000004ca408 RCX: 0000000000445a39 [ 610.429239] RDX: 0000000000000802 RSI: 0000000020000840 RDI: ffffffffffffff9c [ 610.436517] RBP: 00000000004ca400 R08: 0000000000000000 R09: 0000000000000000 [ 610.443892] R10: 0000000000000000 R11: 0000000000000246 R12: 00000000004ca40c [ 610.451692] R13: 000000000049a074 R14: 7974742f7665642f R15: 0000000000022000 [ 610.458991] rcu: rcu_preempt kthread starved for 10540 jiffies! g5245 f0x2 RCU_GP_WAIT_FQS(5) ->state=0x0 ->cpu=1 [ 610.469391] rcu: RCU grace-period kthread stack dump: [ 610.474584] rcu_preempt R running task 29208 10 2 0x80000000 [ 610.481815] Call Trace: [ 610.484433] __schedule+0x887/0x2040 [ 610.488175] ? io_schedule_timeout+0x140/0x140 [ 610.492767] ? _raw_spin_unlock_irqrestore+0x79/0xe0 [ 610.497900] schedule+0x8d/0x1b0 [ 610.501290] schedule_timeout+0x4cf/0xfe0 [ 610.505477] ? prepare_to_swait_event+0x5b/0x540 [ 610.510776] ? usleep_range+0x170/0x170 [ 610.514769] ? _raw_spin_unlock_irqrestore+0x79/0xe0 [ 610.519883] ? lockdep_hardirqs_on+0x3a8/0x5c0 [ 610.524477] ? collect_expired_timers+0x2a0/0x2a0 [ 610.529340] ? swake_up_all+0x340/0x340 [ 610.533343] rcu_gp_kthread+0xdad/0x21c0 [ 610.537427] ? lock_acquire+0x170/0x3c0 [ 610.541429] ? __rcu_read_unlock+0x160/0x160 [ 610.545861] ? _raw_spin_unlock_irqrestore+0x79/0xe0 [ 610.550978] ? lockdep_hardirqs_on+0x3a8/0x5c0 [ 610.555574] ? _raw_spin_unlock_irqrestore+0x66/0xe0 [ 610.560691] ? __kthread_parkme+0x133/0x1e0 [ 610.565024] ? __rcu_read_unlock+0x160/0x160 [ 610.569446] kthread+0x33f/0x460 [ 610.572912] ? kthread_park+0x180/0x180 [ 610.576987] ret_from_fork+0x24/0x30