[....] Starting periodic command scheduler: cron[?25l[?1c7[ ok 8[?25h[?0c. [....] Starting OpenBSD Secure Shell server: sshd[ 24.724383] random: sshd: uninitialized urandom read (32 bytes read) [?25l[?1c7[ ok 8[?25h[?0c. Debian GNU/Linux 7 syzkaller ttyS0 syzkaller login: [ 28.178493] random: sshd: uninitialized urandom read (32 bytes read) [ 28.881825] random: sshd: uninitialized urandom read (32 bytes read) [ 29.658676] random: sshd: uninitialized urandom read (32 bytes read) [ 444.447956] random: sshd: uninitialized urandom read (32 bytes read) Warning: Permanently added '10.128.0.53' (ECDSA) to the list of known hosts. [ 449.886987] random: sshd: uninitialized urandom read (32 bytes read) executing program executing program executing program [ 615.391229] INFO: task syz-executor413:4623 blocked for more than 120 seconds. [ 615.398873] Not tainted 4.17.0-rc6+ #66 [ 615.403469] "echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message. [ 615.411512] syz-executor413 D23216 4623 4621 0x00000000 [ 615.417211] Call Trace: [ 615.419869] __schedule+0x801/0x1e30 [ 615.423655] ? __sched_text_start+0x8/0x8 [ 615.427872] ? do_raw_spin_trylock+0x1b0/0x1b0 [ 615.432522] ? _raw_spin_unlock_irqrestore+0x74/0xc0 [ 615.437684] ? trace_hardirqs_on_caller+0x421/0x5c0 [ 615.442763] ? trace_hardirqs_on+0xd/0x10 [ 615.446996] ? prepare_to_wait_event+0x38e/0xc50 [ 615.451846] ? prepare_to_wait_exclusive+0x540/0x540 [ 615.457068] schedule+0xef/0x430 [ 615.460506] ? __schedule+0x1e30/0x1e30 [ 615.464542] ? check_same_owner+0x320/0x320 [ 615.468922] ? replenish_dl_entity.cold.53+0x37/0x37 [ 615.474130] blk_mq_freeze_queue_wait+0x1ce/0x460 [ 615.479062] ? blk_mq_poll+0x930/0x930 [ 615.483052] ? blk_mq_run_hw_queue+0x119/0x390 [ 615.487699] ? blk_mq_run_work_fn+0x70/0x70 [ 615.492083] ? finish_wait+0x420/0x420 [ 615.496041] blk_freeze_queue+0x4a/0x80 [ 615.500069] blk_mq_freeze_queue+0x15/0x20 [ 615.504400] lo_ioctl+0xa9a/0x2130 [ 615.508068] ? lo_rw_aio_complete+0x430/0x430 [ 615.512624] blkdev_ioctl+0x9b6/0x2020 [ 615.516572] ? blkpg_ioctl+0xc40/0xc40 [ 615.520526] ? trace_hardirqs_on_caller+0x421/0x5c0 [ 615.525609] ? __sanitizer_cov_trace_cmp4+0x16/0x20 [ 615.530702] ? current_kernel_time64+0x1f4/0x2f0 [ 615.535560] ? __sanitizer_cov_trace_const_cmp4+0x16/0x20 [ 615.541363] ? timespec_trunc+0xe7/0x170 [ 615.545505] ? put_itimerspec64+0x310/0x310 [ 615.549903] ? find_held_lock+0x36/0x1c0 [ 615.554046] ? lock_downgrade+0x8e0/0x8e0 [ 615.558260] ? graph_lock+0x170/0x170 [ 615.562123] ? fsnotify+0xfc0/0xfc0 [ 615.565796] ? fsnotify_first_mark+0x330/0x330 [ 615.570451] ? __sanitizer_cov_trace_const_cmp4+0x16/0x20 [ 615.576061] block_ioctl+0xee/0x130 [ 615.579738] ? blkdev_fallocate+0x400/0x400 [ 615.584125] do_vfs_ioctl+0x1cf/0x16a0 [ 615.588102] ? ioctl_preallocate+0x2e0/0x2e0 [ 615.592587] ? fget_raw+0x20/0x20 [ 615.596128] ? __lock_is_held+0xb5/0x140 [ 615.600270] ? security_file_ioctl+0x94/0xc0 [ 615.604746] ksys_ioctl+0xa9/0xd0 [ 615.608273] __x64_sys_ioctl+0x73/0xb0 [ 615.612322] do_syscall_64+0x1b1/0x800 [ 615.616296] ? syscall_return_slowpath+0x5c0/0x5c0 [ 615.621321] ? syscall_return_slowpath+0x30f/0x5c0 [ 615.626367] ? entry_SYSCALL_64_after_hwframe+0x59/0xbe [ 615.631897] ? trace_hardirqs_off_thunk+0x1a/0x1c [ 615.636846] entry_SYSCALL_64_after_hwframe+0x49/0xbe [ 615.642147] RIP: 0033:0x443dc9 [ 615.645398] RSP: 002b:00007ffef2d3a7a8 EFLAGS: 00000286 ORIG_RAX: 0000000000000010 [ 615.653461] RAX: ffffffffffffffda RBX: 6f6f6c2f7665642f RCX: 0000000000443dc9 [ 615.660808] RDX: 0000000000000007 RSI: 0000000000004c06 RDI: 0000000000000007 [ 615.668171] RBP: 00000000006ce018 R08: 00000000004002e0 R09: 00000000004002e0 [ 615.675505] R10: 00000000004002e0 R11: 0000000000000286 R12: 0000000000401a70 [ 615.682866] R13: 0000000000401b00 R14: 0000000000000000 R15: 0000000000000000 [ 615.690230] [ 615.690230] Showing all locks held in the system: [ 615.696651] 2 locks held by khungtaskd/891: [ 615.701141] #0: (ptrval) (rcu_read_lock){....}, at: watchdog+0x1ff/0xf60 [ 615.708871] #1: (ptrval) (tasklist_lock){.+.+}, at: debug_show_all_locks+0xde/0x34a [ 615.717583] 1 lock held by rsyslogd/4506: [ 615.721786] #0: (ptrval) (&f->f_pos_lock){+.+.}, at: __fdget_pos+0x1a9/0x1e0 [ 615.729860] 2 locks held by getty/4597: [ 615.733930] #0: (ptrval) (&tty->ldisc_sem){++++}, at: ldsem_down_read+0x37/0x40 [ 615.742328] #1: (ptrval) (&ldata->atomic_read_lock){+.+.}, at: n_tty_read+0x321/0x1cc0 [ 615.751295] 2 locks held by getty/4598: [ 615.755319] #0: (ptrval) (&tty->ldisc_sem){++++}, at: ldsem_down_read+0x37/0x40 [ 615.763726] #1: (ptrval) (&ldata->atomic_read_lock){+.+.}, at: n_tty_read+0x321/0x1cc0 [ 615.772665] 2 locks held by getty/4599: [ 615.776716] #0: (ptrval) (&tty->ldisc_sem){++++}, at: ldsem_down_read+0x37/0x40 [ 615.785069] #1: (ptrval) (&ldata->atomic_read_lock){+.+.}, at: n_tty_read+0x321/0x1cc0 [ 615.794081] 2 locks held by getty/4600: [ 615.798162] #0: (ptrval) (&tty->ldisc_sem){++++}, at: ldsem_down_read+0x37/0x40 [ 615.806534] #1: (ptrval) (&ldata->atomic_read_lock){+.+.}, at: n_tty_read+0x321/0x1cc0 [ 615.815571] 2 locks held by getty/4601: [ 615.819803] #0: (ptrval) (&tty->ldisc_sem){++++}, at: ldsem_down_read+0x37/0x40 [ 615.828150] #1: (ptrval) (&ldata->atomic_read_lock){+.+.}, at: n_tty_read+0x321/0x1cc0 [ 615.837124] 2 locks held by getty/4602: [ 615.841156] #0: (ptrval) (&tty->ldisc_sem){++++}, at: ldsem_down_read+0x37/0x40 [ 615.849521] #1: (ptrval) (&ldata->atomic_read_lock){+.+.}, at: n_tty_read+0x321/0x1cc0 [ 615.858516] 2 locks held by getty/4603: [ 615.862585] #0: (ptrval) (&tty->ldisc_sem){++++}, at: ldsem_down_read+0x37/0x40 [ 615.870939] #1: (ptrval) (&ldata->atomic_read_lock){+.+.}, at: n_tty_read+0x321/0x1cc0 [ 615.879933] 1 lock held by syz-executor413/4623: [ 615.884793] #0: (ptrval) (&lo->lo_ctl_mutex/1){+.+.}, at: lo_ioctl+0x8d/0x2130 [ 615.893224] [ 615.894896] ============================================= [ 615.894896] [ 615.902131] NMI backtrace for cpu 1 [ 615.905832] CPU: 1 PID: 891 Comm: khungtaskd Not tainted 4.17.0-rc6+ #66 [ 615.912672] Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 [ 615.922206] Call Trace: [ 615.924800] dump_stack+0x1b9/0x294 [ 615.928419] ? dump_stack_print_info.cold.2+0x52/0x52 [ 615.933618] nmi_cpu_backtrace.cold.4+0x19/0xce [ 615.938302] ? lapic_can_unplug_cpu.cold.26+0x3f/0x3f [ 615.943483] nmi_trigger_cpumask_backtrace+0x151/0x192 [ 615.948755] arch_trigger_cpumask_backtrace+0x14/0x20 [ 615.953951] watchdog+0xc10/0xf60 [ 615.957402] ? reset_hung_task_detector+0xb0/0xb0 [ 615.962246] ? __schedule+0x1e30/0x1e30 [ 615.966216] ? do_raw_spin_unlock+0x9e/0x2e0 [ 615.970618] ? do_raw_spin_trylock+0x1b0/0x1b0 [ 615.975192] ? __sanitizer_cov_trace_const_cmp8+0x18/0x20 [ 615.980722] ? __kthread_parkme+0x111/0x1d0 [ 615.985035] ? parse_args.cold.15+0x1b3/0x1b3 [ 615.989520] ? trace_hardirqs_on_caller+0x421/0x5c0 [ 615.994528] ? trace_hardirqs_on+0xd/0x10 [ 615.998676] kthread+0x345/0x410 [ 616.002057] ? reset_hung_task_detector+0xb0/0xb0 [ 616.006927] ? kthread_bind+0x40/0x40 [ 616.010754] ret_from_fork+0x3a/0x50 [ 616.014588] Sending NMI from CPU 1 to CPUs 0: [ 616.019200] NMI backtrace for cpu 0 skipped: idling at native_safe_halt+0x6/0x10 [ 616.020169] Kernel panic - not syncing: hung_task: blocked tasks [ 616.033035] CPU: 1 PID: 891 Comm: khungtaskd Not tainted 4.17.0-rc6+ #66 [ 616.039992] Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 [ 616.049350] Call Trace: [ 616.051958] dump_stack+0x1b9/0x294 [ 616.055603] ? dump_stack_print_info.cold.2+0x52/0x52 [ 616.060801] ? printk_safe_log_store+0x260/0x260 [ 616.065569] panic+0x22f/0x4de [ 616.068760] ? add_taint.cold.5+0x16/0x16 [ 616.072926] ? __sanitizer_cov_trace_const_cmp4+0x16/0x20 [ 616.078549] ? nmi_trigger_cpumask_backtrace+0x13a/0x192 [ 616.084001] ? printk_safe_flush+0xd7/0x130 [ 616.088349] watchdog+0xc21/0xf60 [ 616.091842] ? reset_hung_task_detector+0xb0/0xb0 [ 616.096687] ? __schedule+0x1e30/0x1e30 [ 616.100677] ? do_raw_spin_unlock+0x9e/0x2e0 [ 616.105109] ? do_raw_spin_trylock+0x1b0/0x1b0 [ 616.109711] ? __sanitizer_cov_trace_const_cmp8+0x18/0x20 [ 616.115270] ? __kthread_parkme+0x111/0x1d0 [ 616.119618] ? parse_args.cold.15+0x1b3/0x1b3 [ 616.124134] ? trace_hardirqs_on_caller+0x421/0x5c0 [ 616.129155] ? trace_hardirqs_on+0xd/0x10 [ 616.133305] kthread+0x345/0x410 [ 616.136672] ? reset_hung_task_detector+0xb0/0xb0 [ 616.141508] ? kthread_bind+0x40/0x40 [ 616.145318] ret_from_fork+0x3a/0x50 [ 616.149847] Dumping ftrace buffer: [ 616.154010] (ftrace buffer empty) [ 616.157740] Kernel Offset: disabled [ 616.161370] Rebooting in 86400 seconds..