[....] Starting enhanced syslogd: rsyslogd[?25l[?1c7[ ok 8[?25h[?0c. [ 38.910629][ T26] audit: type=1800 audit(1554342205.604:25): pid=7722 uid=0 auid=4294967295 ses=4294967295 subj=_ op=collect_data cause=failed(directio) comm="startpar" name="cron" dev="sda1" ino=2414 res=0 [ 38.949979][ T26] audit: type=1800 audit(1554342205.604:26): pid=7722 uid=0 auid=4294967295 ses=4294967295 subj=_ op=collect_data cause=failed(directio) comm="startpar" name="mcstrans" dev="sda1" ino=2457 res=0 [ 38.975129][ T26] audit: type=1800 audit(1554342205.614:27): pid=7722 uid=0 auid=4294967295 ses=4294967295 subj=_ op=collect_data cause=failed(directio) comm="startpar" name="restorecond" dev="sda1" ino=2436 res=0 [....] 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 '10.128.0.20' (ECDSA) to the list of known hosts. executing program syzkaller login: [ 465.185800][ T1042] INFO: task syz-executor139:7874 blocked for more than 143 seconds. [ 465.194163][ T1042] Not tainted 5.1.0-rc3+ #50 [ 465.199346][ T1042] "echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message. [ 465.214964][ T1042] syz-executor139 D28216 7874 7872 0x80000000 [ 465.221330][ T1042] Call Trace: [ 465.224613][ T1042] __schedule+0x817/0x1cc0 [ 465.229058][ T1042] ? __sched_text_start+0x8/0x8 [ 465.233895][ T1042] ? __lock_acquire+0x242a/0x3fb0 [ 465.238955][ T1042] schedule+0x92/0x180 [ 465.243011][ T1042] schedule_timeout+0x8ca/0xfd0 [ 465.247884][ T1042] ? wait_for_completion+0x294/0x440 [ 465.253153][ T1042] ? find_held_lock+0x35/0x130 [ 465.258065][ T1042] ? usleep_range+0x170/0x170 [ 465.262735][ T1042] ? kasan_check_write+0x14/0x20 [ 465.267779][ T1042] ? _raw_spin_unlock_irq+0x28/0x90 [ 465.273018][ T1042] ? wait_for_completion+0x294/0x440 [ 465.278347][ T1042] ? _raw_spin_unlock_irq+0x28/0x90 [ 465.283603][ T1042] ? lockdep_hardirqs_on+0x418/0x5d0 [ 465.288932][ T1042] ? trace_hardirqs_on+0x67/0x230 [ 465.293945][ T1042] ? kasan_check_read+0x11/0x20 [ 465.298832][ T1042] wait_for_completion+0x29c/0x440 [ 465.303928][ T1042] ? lockdep_hardirqs_on+0x418/0x5d0 [ 465.309251][ T1042] ? wait_for_completion_interruptible+0x4b0/0x4b0 [ 465.315781][ T1042] ? wake_up_q+0xf0/0xf0 [ 465.320356][ T1042] ? percpu_ref_kill_and_confirm+0x1b7/0x3b0 [ 465.326449][ T1042] exit_aio+0x321/0x3a0 [ 465.330605][ T1042] ? aio_poll_wake+0x11e0/0x11e0 [ 465.335596][ T1042] ? mutex_unlock+0xd/0x10 [ 465.339997][ T1042] mmput+0xcf/0x4c0 [ 465.343783][ T1042] do_exit+0x816/0x2fa0 [ 465.348086][ T1042] ? lock_downgrade+0x880/0x880 [ 465.352934][ T1042] ? __sanitizer_cov_trace_const_cmp4+0x16/0x20 [ 465.359237][ T1042] ? kasan_check_read+0x11/0x20 [ 465.364080][ T1042] ? mm_update_next_owner+0x640/0x640 [ 465.369479][ T1042] ? __x64_sys_io_submit+0x37d/0x580 [ 465.374750][ T1042] ? __ia32_sys_io_destroy+0x420/0x420 [ 465.380241][ T1042] ? trace_hardirqs_on_thunk+0x1a/0x1c [ 465.385776][ T1042] ? trace_hardirqs_on_thunk+0x1a/0x1c [ 465.391228][ T1042] do_group_exit+0x135/0x370 [ 465.395859][ T1042] __x64_sys_exit_group+0x44/0x50 [ 465.400875][ T1042] do_syscall_64+0x103/0x610 [ 465.405449][ T1042] entry_SYSCALL_64_after_hwframe+0x49/0xbe [ 465.411404][ T1042] RIP: 0033:0x43eea8 [ 465.415294][ T1042] Code: Bad RIP value. [ 465.419398][ T1042] RSP: 002b:00007ffd4e1d1c78 EFLAGS: 00000246 ORIG_RAX: 00000000000000e7 [ 465.428191][ T1042] RAX: ffffffffffffffda RBX: 0000000000000000 RCX: 000000000043eea8 [ 465.436210][ T1042] RDX: 0000000000000000 RSI: 000000000000003c RDI: 0000000000000000 [ 465.444173][ T1042] RBP: 00000000004be6a8 R08: 00000000000000e7 R09: ffffffffffffffd0 [ 465.452441][ T1042] R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000001 [ 465.460499][ T1042] R13: 00000000006d0180 R14: 0000000000000000 R15: 0000000000000000 [ 465.468532][ T1042] [ 465.468532][ T1042] Showing all locks held in the system: [ 465.476266][ T1042] 1 lock held by khungtaskd/1042: [ 465.481263][ T1042] #0: 00000000ab953a94 (rcu_read_lock){....}, at: debug_show_all_locks+0x5f/0x27e [ 465.490835][ T1042] 1 lock held by rsyslogd/7760: [ 465.495692][ T1042] #0: 0000000032fb2c44 (&f->f_pos_lock){+.+.}, at: __fdget_pos+0xee/0x110 [ 465.504407][ T1042] 2 locks held by getty/7851: [ 465.509148][ T1042] #0: 0000000080ff068f (&tty->ldisc_sem){++++}, at: ldsem_down_read+0x33/0x40 [ 465.518120][ T1042] #1: 000000006e71bcc5 (&ldata->atomic_read_lock){+.+.}, at: n_tty_read+0x232/0x1b70 [ 465.527707][ T1042] 2 locks held by getty/7852: [ 465.532362][ T1042] #0: 000000006ac866f6 (&tty->ldisc_sem){++++}, at: ldsem_down_read+0x33/0x40 [ 465.541346][ T1042] #1: 000000005ca79f91 (&ldata->atomic_read_lock){+.+.}, at: n_tty_read+0x232/0x1b70 [ 465.550935][ T1042] 2 locks held by getty/7853: [ 465.555640][ T1042] #0: 00000000ebd190bb (&tty->ldisc_sem){++++}, at: ldsem_down_read+0x33/0x40 [ 465.564566][ T1042] #1: 00000000b4f8121b (&ldata->atomic_read_lock){+.+.}, at: n_tty_read+0x232/0x1b70 [ 465.574150][ T1042] 2 locks held by getty/7854: [ 465.578850][ T1042] #0: 000000006c5e4d81 (&tty->ldisc_sem){++++}, at: ldsem_down_read+0x33/0x40 [ 465.587838][ T1042] #1: 0000000068c113b3 (&ldata->atomic_read_lock){+.+.}, at: n_tty_read+0x232/0x1b70 [ 465.597420][ T1042] 2 locks held by getty/7855: [ 465.602074][ T1042] #0: 00000000351b6dc6 (&tty->ldisc_sem){++++}, at: ldsem_down_read+0x33/0x40 [ 465.611062][ T1042] #1: 00000000befff7ae (&ldata->atomic_read_lock){+.+.}, at: n_tty_read+0x232/0x1b70 [ 465.621050][ T1042] 2 locks held by getty/7856: [ 465.625812][ T1042] #0: 00000000618cffe4 (&tty->ldisc_sem){++++}, at: ldsem_down_read+0x33/0x40 [ 465.634744][ T1042] #1: 00000000c73739de (&ldata->atomic_read_lock){+.+.}, at: n_tty_read+0x232/0x1b70 [ 465.644336][ T1042] 2 locks held by getty/7857: [ 465.649018][ T1042] #0: 000000009a761e31 (&tty->ldisc_sem){++++}, at: ldsem_down_read+0x33/0x40 [ 465.658009][ T1042] #1: 000000000cb8711a (&ldata->atomic_read_lock){+.+.}, at: n_tty_read+0x232/0x1b70 [ 465.667777][ T1042] [ 465.670180][ T1042] ============================================= [ 465.670180][ T1042] [ 465.678730][ T1042] NMI backtrace for cpu 0 [ 465.683049][ T1042] CPU: 0 PID: 1042 Comm: khungtaskd Not tainted 5.1.0-rc3+ #50 [ 465.690573][ T1042] Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 [ 465.700607][ T1042] Call Trace: [ 465.703879][ T1042] dump_stack+0x172/0x1f0 [ 465.708203][ T1042] nmi_cpu_backtrace.cold+0x63/0xa4 [ 465.713383][ T1042] ? lapic_can_unplug_cpu.cold+0x38/0x38 [ 465.718998][ T1042] nmi_trigger_cpumask_backtrace+0x1be/0x236 [ 465.724963][ T1042] arch_trigger_cpumask_backtrace+0x14/0x20 [ 465.730905][ T1042] watchdog+0x9b7/0xec0 [ 465.735052][ T1042] kthread+0x357/0x430 [ 465.739103][ T1042] ? reset_hung_task_detector+0x30/0x30 [ 465.744633][ T1042] ? kthread_cancel_delayed_work_sync+0x20/0x20 [ 465.750851][ T1042] ret_from_fork+0x3a/0x50 [ 465.755354][ T1042] Sending NMI from CPU 0 to CPUs 1: [ 465.760657][ C1] NMI backtrace for cpu 1 skipped: idling at native_safe_halt+0x2/0x10 [ 465.761585][ T1042] Kernel panic - not syncing: hung_task: blocked tasks [ 465.775892][ T1042] CPU: 0 PID: 1042 Comm: khungtaskd Not tainted 5.1.0-rc3+ #50 [ 465.783857][ T1042] Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 [ 465.793896][ T1042] Call Trace: [ 465.797169][ T1042] dump_stack+0x172/0x1f0 [ 465.801481][ T1042] panic+0x2cb/0x65c [ 465.805397][ T1042] ? __warn_printk+0xf3/0xf3 [ 465.809974][ T1042] ? __sanitizer_cov_trace_cmp4+0x16/0x20 [ 465.815683][ T1042] ? printk_safe_flush+0xf2/0x140 [ 465.820730][ T1042] ? __sanitizer_cov_trace_const_cmp4+0x16/0x20 [ 465.827018][ T1042] ? lapic_can_unplug_cpu.cold+0x38/0x38 [ 465.832634][ T1042] ? nmi_trigger_cpumask_backtrace+0x1a7/0x236 [ 465.838767][ T1042] ? nmi_trigger_cpumask_backtrace+0x19e/0x236 [ 465.844904][ T1042] watchdog+0x9c8/0xec0 [ 465.849045][ T1042] kthread+0x357/0x430 [ 465.853092][ T1042] ? reset_hung_task_detector+0x30/0x30 [ 465.858618][ T1042] ? kthread_cancel_delayed_work_sync+0x20/0x20 [ 465.864994][ T1042] ret_from_fork+0x3a/0x50 [ 465.870313][ T1042] Kernel Offset: disabled [ 465.874634][ T1042] Rebooting in 86400 seconds..