[....] Starting enhanced syslogd: rsyslogd[?25l[?1c7[ ok 8[?25h[?0c. [ 55.320092][ T26] audit: type=1800 audit(1570387216.262:25): pid=8590 uid=0 auid=4294967295 ses=4294967295 subj==unconfined op=collect_data cause=failed(directio) comm="startpar" name="cron" dev="sda1" ino=2414 res=0 [ 55.360707][ T26] audit: type=1800 audit(1570387216.272:26): pid=8590 uid=0 auid=4294967295 ses=4294967295 subj==unconfined op=collect_data cause=failed(directio) comm="startpar" name="mcstrans" dev="sda1" ino=2457 res=0 [ 55.410192][ T26] audit: type=1800 audit(1570387216.272:27): pid=8590 uid=0 auid=4294967295 ses=4294967295 subj==unconfined 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 '10.128.15.213' (ECDSA) to the list of known hosts. executing program syzkaller login: [ 431.429985][ T8747] block nbd0: shutting down sockets [ 583.740643][ T1064] INFO: task syz-executor374:8747 blocked for more than 143 seconds. [ 583.748817][ T1064] Not tainted 5.4.0-rc1+ #0 [ 583.753913][ T1064] "echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message. [ 583.762629][ T1064] syz-executor374 D27432 8747 8746 0x00004004 [ 583.768954][ T1064] Call Trace: [ 583.772367][ T1064] __schedule+0x94f/0x1e70 [ 583.776859][ T1064] ? __sched_text_start+0x8/0x8 [ 583.781786][ T1064] ? __kasan_check_read+0x11/0x20 [ 583.786809][ T1064] ? __lock_acquire+0x16f2/0x4a00 [ 583.791897][ T1064] schedule+0xd9/0x260 [ 583.795963][ T1064] schedule_timeout+0x717/0xc50 [ 583.800851][ T1064] ? find_held_lock+0x35/0x130 [ 583.805609][ T1064] ? usleep_range+0x170/0x170 [ 583.810543][ T1064] ? lock_downgrade+0x920/0x920 [ 583.815389][ T1064] ? _raw_spin_unlock_irq+0x28/0x90 [ 583.820612][ T1064] ? wait_for_completion+0x294/0x440 [ 583.825885][ T1064] ? _raw_spin_unlock_irq+0x28/0x90 [ 583.831166][ T1064] ? lockdep_hardirqs_on+0x421/0x5e0 [ 583.836456][ T1064] ? trace_hardirqs_on+0x67/0x240 [ 583.842105][ T1064] ? __kasan_check_read+0x11/0x20 [ 583.847116][ T1064] wait_for_completion+0x29c/0x440 [ 583.852280][ T1064] ? wait_for_completion_interruptible+0x470/0x470 [ 583.858777][ T1064] ? wake_up_q+0xf0/0xf0 [ 583.863058][ T1064] ? flush_workqueue_prep_pwqs+0x352/0x590 [ 583.868859][ T1064] ? __sanitizer_cov_trace_const_cmp4+0x16/0x20 [ 583.875156][ T1064] flush_workqueue+0x40f/0x14c0 [ 583.880069][ T1064] ? __dev_printk+0x202/0x20e [ 583.884788][ T1064] ? _dev_warn+0xd7/0x109 [ 583.889127][ T1064] ? pwq_unbound_release_workfn+0x2f0/0x2f0 [ 583.895148][ T1064] ? sock_shutdown+0x194/0x200 [ 583.899908][ T1064] ? sock_shutdown+0x83/0x200 [ 583.904629][ T1064] nbd_ioctl+0xb2e/0xc44 [ 583.908867][ T1064] ? nbd_ioctl+0xb2e/0xc44 [ 583.913345][ T1064] ? nbd_release+0x150/0x150 [ 583.917946][ T1064] ? finish_wait+0x260/0x260 [ 583.922571][ T1064] ? nbd_release+0x150/0x150 [ 583.927154][ T1064] blkdev_ioctl+0xedb/0x1c20 [ 583.931782][ T1064] ? blkpg_ioctl+0xa90/0xa90 [ 583.936369][ T1064] ? tomoyo_execute_permission+0x4a0/0x4a0 [ 583.942243][ T1064] ? __sanitizer_cov_trace_const_cmp4+0x16/0x20 [ 583.948478][ T1064] block_ioctl+0xee/0x130 [ 583.953451][ T1064] ? blkdev_fallocate+0x410/0x410 [ 583.958488][ T1064] do_vfs_ioctl+0xdb6/0x13e0 [ 583.963110][ T1064] ? ioctl_preallocate+0x210/0x210 [ 583.968219][ T1064] ? kmem_cache_free+0x26b/0x320 [ 583.973786][ T1064] ? putname+0xf4/0x130 [ 583.977944][ T1064] ? do_sys_open+0x31d/0x5d0 [ 583.982562][ T1064] ? tomoyo_file_ioctl+0x23/0x30 [ 583.987493][ T1064] ? __sanitizer_cov_trace_const_cmp4+0x16/0x20 [ 583.993787][ T1064] ? security_file_ioctl+0x8d/0xc0 [ 583.998891][ T1064] ksys_ioctl+0xab/0xd0 [ 584.003078][ T1064] __x64_sys_ioctl+0x73/0xb0 [ 584.007665][ T1064] do_syscall_64+0xfa/0x760 [ 584.012221][ T1064] entry_SYSCALL_64_after_hwframe+0x49/0xbe [ 584.018109][ T1064] RIP: 0033:0x444e49 [ 584.022069][ T1064] Code: Bad RIP value. [ 584.026146][ T1064] RSP: 002b:00007fff1aa69b78 EFLAGS: 00000246 ORIG_RAX: 0000000000000010 [ 584.034614][ T1064] RAX: ffffffffffffffda RBX: 0000000000000000 RCX: 0000000000444e49 [ 584.042616][ T1064] RDX: 0000000000000000 RSI: 000000000000ab03 RDI: 0000000000000004 [ 584.050624][ T1064] RBP: 00000000006cf018 R08: 00000000004002e0 R09: 00000000004002e0 [ 584.058590][ T1064] R10: 00000000004002e0 R11: 0000000000000246 R12: 0000000000402090 [ 584.066617][ T1064] R13: 0000000000402120 R14: 0000000000000000 R15: 0000000000000000 [ 584.074636][ T1064] [ 584.074636][ T1064] Showing all locks held in the system: [ 584.082382][ T1064] 1 lock held by khungtaskd/1064: [ 584.087396][ T1064] #0: ffffffff88faae00 (rcu_read_lock){....}, at: debug_show_all_locks+0x5f/0x27e [ 584.096747][ T1064] 2 locks held by kworker/u5:0/1523: [ 584.102540][ T1064] #0: ffff88809516b168 ((wq_completion)knbd0-recv){+.+.}, at: process_one_work+0x88b/0x1740 [ 584.112741][ T1064] #1: ffff8880a61b7dc0 ((work_completion)(&args->work)){+.+.}, at: process_one_work+0x8c1/0x1740 [ 584.123402][ T1064] 1 lock held by rsyslogd/8628: [ 584.128225][ T1064] #0: ffff8880a84f26a0 (&f->f_pos_lock){+.+.}, at: __fdget_pos+0xee/0x110 [ 584.136861][ T1064] 2 locks held by getty/8718: [ 584.141552][ T1064] #0: ffff88808fd43410 (&tty->ldisc_sem){++++}, at: ldsem_down_read+0x33/0x40 [ 584.150526][ T1064] #1: ffffc90005f1d2e0 (&ldata->atomic_read_lock){+.+.}, at: n_tty_read+0x232/0x1c10 [ 584.160085][ T1064] 2 locks held by getty/8719: [ 584.164800][ T1064] #0: ffff888099070610 (&tty->ldisc_sem){++++}, at: ldsem_down_read+0x33/0x40 [ 584.173783][ T1064] #1: ffffc90005f312e0 (&ldata->atomic_read_lock){+.+.}, at: n_tty_read+0x232/0x1c10 [ 584.183380][ T1064] 2 locks held by getty/8720: [ 584.188042][ T1064] #0: ffff88808713d750 (&tty->ldisc_sem){++++}, at: ldsem_down_read+0x33/0x40 [ 584.197033][ T1064] #1: ffffc90005f352e0 (&ldata->atomic_read_lock){+.+.}, at: n_tty_read+0x232/0x1c10 [ 584.206620][ T1064] 2 locks held by getty/8721: [ 584.211326][ T1064] #0: ffff8880a7858e10 (&tty->ldisc_sem){++++}, at: ldsem_down_read+0x33/0x40 [ 584.220270][ T1064] #1: ffffc90005f392e0 (&ldata->atomic_read_lock){+.+.}, at: n_tty_read+0x232/0x1c10 [ 584.229892][ T1064] 2 locks held by getty/8722: [ 584.235071][ T1064] #0: ffff888090d155d0 (&tty->ldisc_sem){++++}, at: ldsem_down_read+0x33/0x40 [ 584.244061][ T1064] #1: ffffc90005f212e0 (&ldata->atomic_read_lock){+.+.}, at: n_tty_read+0x232/0x1c10 [ 584.253664][ T1064] 2 locks held by getty/8723: [ 584.258322][ T1064] #0: ffff888086809590 (&tty->ldisc_sem){++++}, at: ldsem_down_read+0x33/0x40 [ 584.267303][ T1064] #1: ffffc90005f192e0 (&ldata->atomic_read_lock){+.+.}, at: n_tty_read+0x232/0x1c10 [ 584.276911][ T1064] 2 locks held by getty/8724: [ 584.281600][ T1064] #0: ffff88808ede62d0 (&tty->ldisc_sem){++++}, at: ldsem_down_read+0x33/0x40 [ 584.290577][ T1064] #1: ffffc90005f012e0 (&ldata->atomic_read_lock){+.+.}, at: n_tty_read+0x232/0x1c10 [ 584.300125][ T1064] [ 584.302475][ T1064] ============================================= [ 584.302475][ T1064] [ 584.310905][ T1064] NMI backtrace for cpu 0 [ 584.315212][ T1064] CPU: 0 PID: 1064 Comm: khungtaskd Not tainted 5.4.0-rc1+ #0 [ 584.322645][ T1064] Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 [ 584.332690][ T1064] Call Trace: [ 584.336014][ T1064] dump_stack+0x172/0x1f0 [ 584.340332][ T1064] nmi_cpu_backtrace.cold+0x70/0xb2 [ 584.345508][ T1064] ? __sanitizer_cov_trace_const_cmp4+0x16/0x20 [ 584.351734][ T1064] ? lapic_can_unplug_cpu.cold+0x3a/0x3a [ 584.357343][ T1064] nmi_trigger_cpumask_backtrace+0x23b/0x28b [ 584.363300][ T1064] arch_trigger_cpumask_backtrace+0x14/0x20 [ 584.369167][ T1064] watchdog+0x9d0/0xef0 [ 584.373304][ T1064] kthread+0x361/0x430 [ 584.377367][ T1064] ? reset_hung_task_detector+0x30/0x30 [ 584.382893][ T1064] ? kthread_cancel_delayed_work_sync+0x20/0x20 [ 584.389116][ T1064] ret_from_fork+0x24/0x30 [ 584.393703][ T1064] Sending NMI from CPU 0 to CPUs 1: [ 584.398967][ C1] NMI backtrace for cpu 1 skipped: idling at native_safe_halt+0xe/0x10 [ 584.400808][ T1064] Kernel panic - not syncing: hung_task: blocked tasks [ 584.414038][ T1064] CPU: 0 PID: 1064 Comm: khungtaskd Not tainted 5.4.0-rc1+ #0 [ 584.421469][ T1064] Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 [ 584.431501][ T1064] Call Trace: [ 584.434793][ T1064] dump_stack+0x172/0x1f0 [ 584.439104][ T1064] panic+0x2dc/0x755 [ 584.442975][ T1064] ? add_taint.cold+0x16/0x16 [ 584.447646][ T1064] ? lapic_can_unplug_cpu.cold+0x3a/0x3a [ 584.453314][ T1064] ? ___preempt_schedule+0x16/0x20 [ 584.458419][ T1064] ? nmi_trigger_cpumask_backtrace+0x21b/0x28b [ 584.464556][ T1064] ? nmi_trigger_cpumask_backtrace+0x24c/0x28b [ 584.470726][ T1064] ? nmi_trigger_cpumask_backtrace+0x256/0x28b [ 584.476860][ T1064] ? nmi_trigger_cpumask_backtrace+0x21b/0x28b [ 584.482998][ T1064] watchdog+0x9e1/0xef0 [ 584.487136][ T1064] kthread+0x361/0x430 [ 584.491202][ T1064] ? reset_hung_task_detector+0x30/0x30 [ 584.496725][ T1064] ? kthread_cancel_delayed_work_sync+0x20/0x20 [ 584.502945][ T1064] ret_from_fork+0x24/0x30 [ 584.508705][ T1064] Kernel Offset: disabled [ 584.513038][ T1064] Rebooting in 86400 seconds..