[....] Starting periodic command scheduler: cron[?25l[?1c7[ ok 8[?25h[?0c. [....] Starting OpenBSD Secure Shell server: sshd[ 22.294246] random: sshd: uninitialized urandom read (32 bytes read) [?25l[?1c7[ ok 8[?25h[?0c. [ 22.616959] random: sshd: uninitialized urandom read (32 bytes read) [ 22.984984] random: sshd: uninitialized urandom read (32 bytes read) Debian GNU/Linux 7 syzkaller ttyS0 syzkaller login: [ 23.774330] random: sshd: uninitialized urandom read (32 bytes read) [ 321.991258] random: sshd: uninitialized urandom read (32 bytes read) Warning: Permanently added '10.128.0.4' (ECDSA) to the list of known hosts. [ 327.578470] random: sshd: uninitialized urandom read (32 bytes read) executing program executing program executing program [ 492.511249] INFO: task syz-executor064:4600 blocked for more than 120 seconds. [ 492.518890] Not tainted 4.17.0-rc6+ #66 [ 492.523465] "echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message. [ 492.531475] syz-executor064 D23216 4600 4598 0x00000000 [ 492.537248] Call Trace: [ 492.539989] __schedule+0x801/0x1e30 [ 492.543755] ? __sched_text_start+0x8/0x8 [ 492.547997] ? do_raw_spin_trylock+0x1b0/0x1b0 [ 492.552687] ? _raw_spin_unlock_irqrestore+0x74/0xc0 [ 492.557858] ? trace_hardirqs_on_caller+0x421/0x5c0 [ 492.562939] ? trace_hardirqs_on+0xd/0x10 [ 492.567187] ? prepare_to_wait_event+0x38e/0xc50 [ 492.572041] ? prepare_to_wait_exclusive+0x540/0x540 [ 492.577178] ? find_held_lock+0x36/0x1c0 [ 492.581284] schedule+0xef/0x430 [ 492.584681] ? __schedule+0x1e30/0x1e30 [ 492.588765] ? check_same_owner+0x320/0x320 [ 492.593141] ? replenish_dl_entity.cold.53+0x37/0x37 [ 492.598282] ? __might_sleep+0x95/0x190 [ 492.602353] blk_mq_freeze_queue_wait+0x1ce/0x460 [ 492.607232] ? blk_mq_poll+0x930/0x930 [ 492.611155] ? blk_mq_run_hw_queue+0x119/0x390 [ 492.615767] ? blk_mq_run_work_fn+0x70/0x70 [ 492.620391] ? finish_wait+0x420/0x420 [ 492.624325] blk_freeze_queue+0x4a/0x80 [ 492.628349] blk_mq_freeze_queue+0x15/0x20 [ 492.632709] lo_ioctl+0xa9a/0x2130 [ 492.636325] ? lo_rw_aio_complete+0x430/0x430 [ 492.640901] blkdev_ioctl+0x9b6/0x2020 [ 492.644832] ? blkpg_ioctl+0xc40/0xc40 [ 492.648762] ? trace_hardirqs_on_caller+0x421/0x5c0 [ 492.653873] ? __sanitizer_cov_trace_cmp4+0x16/0x20 [ 492.658968] ? current_kernel_time64+0x1f4/0x2f0 [ 492.663846] ? __sanitizer_cov_trace_const_cmp4+0x16/0x20 [ 492.669500] ? timespec_trunc+0xe7/0x170 [ 492.673760] ? put_itimerspec64+0x310/0x310 [ 492.678157] ? find_held_lock+0x36/0x1c0 [ 492.682267] ? lock_downgrade+0x8e0/0x8e0 [ 492.686480] ? graph_lock+0x170/0x170 [ 492.690423] ? fsnotify+0xfc0/0xfc0 [ 492.694107] ? fsnotify_first_mark+0x330/0x330 [ 492.698755] ? __sanitizer_cov_trace_const_cmp4+0x16/0x20 [ 492.704404] block_ioctl+0xee/0x130 [ 492.708116] ? blkdev_fallocate+0x400/0x400 [ 492.712524] do_vfs_ioctl+0x1cf/0x16a0 [ 492.716464] ? ioctl_preallocate+0x2e0/0x2e0 [ 492.720930] ? fget_raw+0x20/0x20 [ 492.724434] ? __lock_is_held+0xb5/0x140 [ 492.728618] ? security_file_ioctl+0x94/0xc0 [ 492.733071] ksys_ioctl+0xa9/0xd0 [ 492.736582] __x64_sys_ioctl+0x73/0xb0 [ 492.740540] do_syscall_64+0x1b1/0x800 [ 492.744469] ? syscall_return_slowpath+0x5c0/0x5c0 [ 492.749437] ? syscall_return_slowpath+0x30f/0x5c0 [ 492.754406] ? entry_SYSCALL_64_after_hwframe+0x59/0xbe [ 492.759804] ? trace_hardirqs_off_thunk+0x1a/0x1c [ 492.764733] entry_SYSCALL_64_after_hwframe+0x49/0xbe [ 492.769978] RIP: 0033:0x443dc9 [ 492.773236] RSP: 002b:00007fffb864b8b8 EFLAGS: 00000286 ORIG_RAX: 0000000000000010 [ 492.780999] RAX: ffffffffffffffda RBX: 6f6f6c2f7665642f RCX: 0000000000443dc9 [ 492.788362] RDX: 0000000000000007 RSI: 0000000000004c06 RDI: 0000000000000007 [ 492.795739] RBP: 00000000006ce018 R08: 00000000004002e0 R09: 00000000004002e0 [ 492.803069] R10: 00000000004002e0 R11: 0000000000000286 R12: 0000000000401a70 [ 492.810379] R13: 0000000000401b00 R14: 0000000000000000 R15: 0000000000000000 [ 492.817793] [ 492.817793] Showing all locks held in the system: [ 492.824235] 2 locks held by khungtaskd/894: [ 492.828715] #0: (ptrval) (rcu_read_lock){....}, at: watchdog+0x1ff/0xf60 [ 492.836490] #1: (ptrval) (tasklist_lock){.+.+}, at: debug_show_all_locks+0xde/0x34a [ 492.845245] 1 lock held by rsyslogd/4482: [ 492.849439] #0: (ptrval) (&f->f_pos_lock){+.+.}, at: __fdget_pos+0x1a9/0x1e0 [ 492.857493] 2 locks held by getty/4572: [ 492.861526] #0: (ptrval) (&tty->ldisc_sem){++++}, at: ldsem_down_read+0x37/0x40 [ 492.869936] #1: (ptrval) (&ldata->atomic_read_lock){+.+.}, at: n_tty_read+0x321/0x1cc0 [ 492.878983] 2 locks held by getty/4573: [ 492.882999] #0: (ptrval) (&tty->ldisc_sem){++++}, at: ldsem_down_read+0x37/0x40 [ 492.891309] #1: (ptrval) (&ldata->atomic_read_lock){+.+.}, at: n_tty_read+0x321/0x1cc0 [ 492.900277] 2 locks held by getty/4574: [ 492.904306] #0: (ptrval) (&tty->ldisc_sem){++++}, at: ldsem_down_read+0x37/0x40 [ 492.912661] #1: (ptrval) (&ldata->atomic_read_lock){+.+.}, at: n_tty_read+0x321/0x1cc0 [ 492.922066] 2 locks held by getty/4575: [ 492.926121] #0: (ptrval) (&tty->ldisc_sem){++++}, at: ldsem_down_read+0x37/0x40 [ 492.934436] #1: (ptrval) (&ldata->atomic_read_lock){+.+.}, at: n_tty_read+0x321/0x1cc0 [ 492.943477] 2 locks held by getty/4576: [ 492.947510] #0: (ptrval) (&tty->ldisc_sem){++++}, at: ldsem_down_read+0x37/0x40 [ 492.956075] #1: (ptrval) (&ldata->atomic_read_lock){+.+.}, at: n_tty_read+0x321/0x1cc0 [ 492.965195] 2 locks held by getty/4577: [ 492.969252] #0: (ptrval) (&tty->ldisc_sem){++++}, at: ldsem_down_read+0x37/0x40 [ 492.977592] #1: (ptrval) (&ldata->atomic_read_lock){+.+.}, at: n_tty_read+0x321/0x1cc0 [ 492.986551] 2 locks held by getty/4578: [ 492.990563] #0: (ptrval) (&tty->ldisc_sem){++++}, at: ldsem_down_read+0x37/0x40 [ 492.998883] #1: (ptrval) (&ldata->atomic_read_lock){+.+.}, at: n_tty_read+0x321/0x1cc0 [ 493.007821] 1 lock held by syz-executor064/4600: [ 493.012615] #0: (ptrval) (&lo->lo_ctl_mutex/1){+.+.}, at: lo_ioctl+0x8d/0x2130 [ 493.020871] [ 493.022569] ============================================= [ 493.022569] [ 493.029675] NMI backtrace for cpu 1 [ 493.033450] CPU: 1 PID: 894 Comm: khungtaskd Not tainted 4.17.0-rc6+ #66 [ 493.040290] Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 [ 493.049635] Call Trace: [ 493.052309] dump_stack+0x1b9/0x294 [ 493.055942] ? dump_stack_print_info.cold.2+0x52/0x52 [ 493.061146] nmi_cpu_backtrace.cold.4+0x19/0xce [ 493.065937] ? lapic_can_unplug_cpu.cold.26+0x3f/0x3f [ 493.071137] nmi_trigger_cpumask_backtrace+0x151/0x192 [ 493.076419] arch_trigger_cpumask_backtrace+0x14/0x20 [ 493.081615] watchdog+0xc10/0xf60 [ 493.085075] ? reset_hung_task_detector+0xb0/0xb0 [ 493.089910] ? __schedule+0x1e30/0x1e30 [ 493.093873] ? do_raw_spin_unlock+0x9e/0x2e0 [ 493.098290] ? do_raw_spin_trylock+0x1b0/0x1b0 [ 493.102867] ? __sanitizer_cov_trace_const_cmp8+0x18/0x20 [ 493.108457] ? __kthread_parkme+0x111/0x1d0 [ 493.112774] ? parse_args.cold.15+0x1b3/0x1b3 [ 493.117267] ? trace_hardirqs_on_caller+0x421/0x5c0 [ 493.122300] ? trace_hardirqs_on+0xd/0x10 [ 493.126450] kthread+0x345/0x410 [ 493.129812] ? reset_hung_task_detector+0xb0/0xb0 [ 493.134636] ? kthread_bind+0x40/0x40 [ 493.138449] ret_from_fork+0x3a/0x50 [ 493.142264] Sending NMI from CPU 1 to CPUs 0: [ 493.146848] NMI backtrace for cpu 0 skipped: idling at native_safe_halt+0x6/0x10 [ 493.147826] Kernel panic - not syncing: hung_task: blocked tasks [ 493.160660] CPU: 1 PID: 894 Comm: khungtaskd Not tainted 4.17.0-rc6+ #66 [ 493.167497] Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 [ 493.176861] Call Trace: [ 493.179458] dump_stack+0x1b9/0x294 [ 493.183104] ? dump_stack_print_info.cold.2+0x52/0x52 [ 493.188332] ? printk_safe_log_store+0x260/0x260 [ 493.193145] panic+0x22f/0x4de [ 493.196353] ? add_taint.cold.5+0x16/0x16 [ 493.200508] ? __sanitizer_cov_trace_const_cmp4+0x16/0x20 [ 493.206143] ? nmi_trigger_cpumask_backtrace+0x13a/0x192 [ 493.211613] ? printk_safe_flush+0xd7/0x130 [ 493.215934] watchdog+0xc21/0xf60 [ 493.219388] ? reset_hung_task_detector+0xb0/0xb0 [ 493.225160] ? __schedule+0x1e30/0x1e30 [ 493.229245] ? do_raw_spin_unlock+0x9e/0x2e0 [ 493.233669] ? do_raw_spin_trylock+0x1b0/0x1b0 [ 493.238254] ? __sanitizer_cov_trace_const_cmp8+0x18/0x20 [ 493.243788] ? __kthread_parkme+0x111/0x1d0 [ 493.248194] ? parse_args.cold.15+0x1b3/0x1b3 [ 493.252684] ? trace_hardirqs_on_caller+0x421/0x5c0 [ 493.257691] ? trace_hardirqs_on+0xd/0x10 [ 493.261836] kthread+0x345/0x410 [ 493.265218] ? reset_hung_task_detector+0xb0/0xb0 [ 493.270104] ? kthread_bind+0x40/0x40 [ 493.273923] ret_from_fork+0x3a/0x50 [ 493.278273] Dumping ftrace buffer: [ 493.281974] (ftrace buffer empty) [ 493.285681] Kernel Offset: disabled [ 493.289301] Rebooting in 86400 seconds..