[ OK ] Reached target Login Prompts. [ OK ] Reached target Multi-User System. [ OK ] Reached target Graphical Interface. Starting Update UTMP about System Runlevel Changes... Starting Load/Save RF Kill Switch Status... Debian GNU/Linux 9 syzkaller ttyS0 Warning: Permanently added '10.128.0.202' (ECDSA) to the list of known hosts. syzkaller login: [ 315.087182] IPVS: ftp: loaded support on port[0] = 21 [ 315.089199] IPVS: ftp: loaded support on port[0] = 21 [ 315.104374] IPVS: ftp: loaded support on port[0] = 21 [ 315.107746] IPVS: ftp: loaded support on port[0] = 21 [ 315.117837] IPVS: ftp: loaded support on port[0] = 21 [ 315.132514] IPVS: ftp: loaded support on port[0] = 21 executing program executing program executing program executing program executing program executing program [ 420.413267] rcu: INFO: rcu_preempt detected stalls on CPUs/tasks: [ 420.419636] rcu: (detected by 1, t=10502 jiffies, g=4197, q=4) [ 420.425697] rcu: All QSes seen, last rcu_preempt kthread activity 10503 (4294979028-4294968525), jiffies_till_next_fqs=1, root ->qsmask 0x0 [ 420.438339] syz-executor998 R running task 27536 8278 8131 0x00000000 [ 420.445526] Call Trace: [ 420.448104] [ 420.450252] sched_show_task.cold+0x332/0x396 [ 420.454745] ? __se_sys_sched_getattr+0x480/0x480 [ 420.459592] rcu_check_callbacks.cold+0xb37/0xe19 [ 420.464447] update_process_times+0x2a/0x70 [ 420.468762] tick_sched_handle+0x9b/0x180 [ 420.472906] tick_sched_timer+0xfc/0x290 [ 420.476967] __hrtimer_run_queues+0x3f6/0xe60 [ 420.481462] ? tick_nohz_restart_sched_tick+0x310/0x310 [ 420.486826] ? hrtimer_fixup_free+0xa0/0xa0 [ 420.491141] ? kvm_clock_get_cycles+0x14/0x30 [ 420.495634] ? ktime_get_update_offsets_now+0x2ec/0x460 [ 420.500999] hrtimer_interrupt+0x326/0x9e0 [ 420.505245] smp_apic_timer_interrupt+0x10c/0x550 [ 420.510086] apic_timer_interrupt+0xf/0x20 [ 420.514306] [ 420.516539] RIP: 0010:_raw_spin_unlock_irq+0x50/0x80 [ 420.521702] Code: c0 98 82 f1 89 48 ba 00 00 00 00 00 fc ff df 48 c1 e8 03 80 3c 10 00 75 31 48 83 3d 01 31 d8 01 00 74 25 fb 66 0f 1f 44 00 00 01 00 00 00 e8 26 1b 28 f9 65 8b 05 9f 8d e8 77 85 c0 74 02 5d [ 420.540596] RSP: 0018:ffff8880956b75f0 EFLAGS: 00000286 ORIG_RAX: ffffffffffffff13 [ 420.548305] RAX: 1ffffffff13e3053 RBX: ffff8880b2fee200 RCX: 1ffff110165fdd55 [ 420.555565] RDX: dffffc0000000000 RSI: ffff8880b2feea88 RDI: ffff8880b2feea84 [ 420.562839] RBP: ffff8880ba12b0c0 R08: 0000000000000000 R09: 0000000000000000 [ 420.570110] R10: 0000000000000000 R11: 0000000000000000 R12: ffff8880ba12b0c0 [ 420.577459] R13: ffff8880af808000 R14: 0000000000000000 R15: 0000000000000001 [ 420.584752] finish_task_switch+0x146/0x760 [ 420.589073] ? finish_task_switch+0x118/0x760 [ 420.593564] ? switch_mm_irqs_off+0x2e5/0x1340 [ 420.598148] __schedule+0x88f/0x2040 [ 420.601859] ? io_schedule_timeout+0x140/0x140 [ 420.606442] ? rcu_nmi_exit+0xb3/0x180 [ 420.610335] ? ___preempt_schedule+0x16/0x18 [ 420.614739] preempt_schedule_common+0x45/0xc0 [ 420.619316] ___preempt_schedule+0x16/0x18 [ 420.623551] _raw_spin_unlock_irqrestore+0xaf/0xe0 [ 420.628479] __wake_up_common_lock+0xe0/0x170 [ 420.632979] ? __wake_up_common+0x650/0x650 [ 420.637308] ? proto_seq_start+0x50/0x50 [ 420.641374] unix_dgram_recvmsg+0x2db/0xdb0 [ 420.645703] ? unix_stream_read_actor+0xc0/0xc0 [ 420.650366] ? __might_fault+0x192/0x1d0 [ 420.654424] ? copy_msghdr_from_user+0x267/0x440 [ 420.659174] ? kernel_recvmsg+0x220/0x220 [ 420.663326] ? __sock_tx_timestamp+0xc0/0xc0 [ 420.667727] ___sys_recvmsg+0x255/0x570 [ 420.671697] ? ___sys_sendmsg+0x8e0/0x8e0 [ 420.675840] ? mark_held_locks+0xf0/0xf0 [ 420.679897] ? trace_hardirqs_on_thunk+0x1a/0x1c [ 420.684647] ? lockdep_hardirqs_on+0x3a8/0x5c0 [ 420.689226] ? trace_hardirqs_on_thunk+0x1a/0x1c [ 420.693979] ? rcu_nmi_exit+0xb3/0x180 [ 420.697862] ? retint_kernel+0x2d/0x2d [ 420.701762] __sys_recvmmsg+0x254/0x6d0 [ 420.705734] ? __ia32_sys_recvmsg+0x220/0x220 [ 420.710224] ? check_preemption_disabled+0x41/0x280 [ 420.715232] ? trace_hardirqs_on_thunk+0x1a/0x1c [ 420.719989] ? lockdep_hardirqs_on+0x3a8/0x5c0 [ 420.724575] ? trace_hardirqs_on_thunk+0x1a/0x1c [ 420.730193] ? rcu_nmi_exit+0xb3/0x180 [ 420.734081] ? trace_hardirqs_on_thunk+0x1a/0x1c [ 420.738830] ? lockdep_hardirqs_on+0x3a8/0x5c0 [ 420.743409] do_sys_recvmmsg+0x172/0x190 [ 420.747463] ? __sys_recvmmsg+0x6d0/0x6d0 [ 420.751609] __x64_sys_recvmmsg+0xba/0x150 [ 420.755841] ? do_syscall_64+0x56/0x620 [ 420.759808] do_syscall_64+0xf9/0x620 [ 420.763615] entry_SYSCALL_64_after_hwframe+0x49/0xbe [ 420.768800] RIP: 0033:0x7f63aa090e09 [ 420.772509] Code: 28 00 00 00 75 05 48 83 c4 28 c3 e8 71 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 [ 420.791404] RSP: 002b:00007f63aa021308 EFLAGS: 00000246 ORIG_RAX: 000000000000012b [ 420.799106] RAX: ffffffffffffffda RBX: 0000000000000009 RCX: 00007f63aa090e09 [ 420.806368] RDX: 0000000000010106 RSI: 00000000200000c0 RDI: 0000000000000003 [ 420.813629] RBP: 00007f63aa11a418 R08: 0000000000000000 R09: 0000000000000000 [ 420.820890] R10: 0000000000000002 R11: 0000000000000246 R12: 00007f63aa11a410 [ 420.828157] R13: 00007f63aa0e71a4 R14: 00007f63aa021400 R15: 0000000000022000 [ 420.835443] rcu: rcu_preempt kthread starved for 10544 jiffies! g4197 f0x2 RCU_GP_WAIT_FQS(5) ->state=0x0 ->cpu=0 [ 420.845828] rcu: RCU grace-period kthread stack dump: [ 420.851095] rcu_preempt R running task 29208 10 2 0x80000000 [ 420.858286] Call Trace: [ 420.860878] __schedule+0x887/0x2040 [ 420.864590] ? scheduler_ipi+0xfa/0x5a0 [ 420.868560] ? io_schedule_timeout+0x140/0x140 [ 420.873138] ? ___preempt_schedule+0x16/0x18 [ 420.877574] schedule+0x8d/0x1b0 [ 420.880941] schedule_timeout+0x4cf/0xfe0 [ 420.885082] ? prepare_to_swait_event+0x5b/0x540 [ 420.889840] ? usleep_range+0x170/0x170 [ 420.893809] ? _raw_spin_unlock_irqrestore+0x79/0xe0 [ 420.898916] ? lockdep_hardirqs_on+0x3a8/0x5c0 [ 420.903501] ? collect_expired_timers+0x2a0/0x2a0 [ 420.908339] ? swake_up_all+0x340/0x340 [ 420.912312] rcu_gp_kthread+0xdad/0x21c0 [ 420.916381] ? lock_acquire+0x170/0x3c0 [ 420.920351] ? __rcu_read_unlock+0x160/0x160 [ 420.924757] ? _raw_spin_unlock_irqrestore+0x79/0xe0 [ 420.929856] ? lockdep_hardirqs_on+0x3a8/0x5c0 [ 420.934431] ? _raw_spin_unlock_irqrestore+0x66/0xe0 [ 420.939534] ? __kthread_parkme+0x133/0x1e0 [ 420.943849] ? __rcu_read_unlock+0x160/0x160 [ 420.948251] kthread+0x33f/0x460 [ 420.951614] ? kthread_park+0x180/0x180 [ 420.955594] ret_from_fork+0x24/0x30