[....] Starting enhanced syslogd: rsyslogd[?25l[?1c7[ ok 8[?25h[?0c. [....] Starting periodic command scheduler: cron[?25l[?1c7[ ok 8[?25h[?0c. [....] Starting OpenBSD Secure Shell server: sshd[ 22.068652] random: sshd: uninitialized urandom read (32 bytes read) [?25l[?1c7[ ok 8[?25h[?0c. Debian GNU/Linux 7 syzkaller ttyS0 syzkaller login: [ 25.272551] random: sshd: uninitialized urandom read (32 bytes read) [ 25.511193] random: sshd: uninitialized urandom read (32 bytes read) [ 26.146891] random: sshd: uninitialized urandom read (32 bytes read) Warning: Permanently added '10.128.10.36' (ECDSA) to the list of known hosts. [ 31.758341] random: sshd: uninitialized urandom read (32 bytes read) 2018/09/05 09:53:04 fuzzer started [ 32.833417] random: cc1: uninitialized urandom read (8 bytes read) 2018/09/05 09:53:06 connecting to host at 10.128.0.26:38523 2018/09/05 09:53:06 checking revisions... 2018/09/05 09:53:06 testing simple program... executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program [ 185.222158] INFO: task syz-fuzzer:4868 blocked for more than 140 seconds. [ 185.229496] Not tainted 4.19.0-rc2-next-20180905+ #57 [ 185.235273] "echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message. [ 185.243300] syz-fuzzer D21704 4868 4866 0x00000000 [ 185.249017] Call Trace: [ 185.251677] __schedule+0x87c/0x1df0 [ 185.255497] ? __sched_text_start+0x8/0x8 [ 185.259709] ? ext4_set_page_dirty+0x254/0x340 [ 185.264352] ? graph_lock+0x170/0x170 [ 185.268214] ? print_usage_bug+0xc0/0xc0 [ 185.272349] ? __sanitizer_cov_trace_const_cmp8+0x18/0x20 [ 185.277947] ? find_held_lock+0x36/0x1c0 [ 185.282145] schedule+0xfb/0x450 [ 185.285564] ? mark_held_locks+0xc9/0x160 [ 185.289775] ? __schedule+0x1df0/0x1df0 [ 185.293812] ? _raw_spin_unlock_irq+0x27/0x70 [ 185.298377] ? _raw_spin_unlock_irq+0x27/0x70 [ 185.302924] ? lockdep_hardirqs_on+0x421/0x5c0 [ 185.307606] ? trace_hardirqs_on+0xbd/0x2c0 [ 185.312003] ? kasan_check_read+0x11/0x20 [ 185.316224] ? __lock_page+0x585/0x7a0 [ 185.320175] ? trace_hardirqs_off_caller+0x2b0/0x2b0 [ 185.325351] ? kasan_check_write+0x14/0x20 [ 185.329645] io_schedule+0x1c/0x70 [ 185.333270] __lock_page+0x5b7/0x7a0 [ 185.337058] ? __lock_page_killable+0x850/0x850 [ 185.341857] ? __sb_end_write+0xac/0xe0 [ 185.345899] ? ext4_page_mkwrite+0xa95/0x1450 [ 185.350457] ? page_cache_tree_insert+0x560/0x560 [ 185.355364] ? __lock_is_held+0xb5/0x140 [ 185.359507] ? check_same_owner+0x340/0x340 [ 185.363903] ? rcu_note_context_switch+0x680/0x680 [ 185.368898] do_page_mkwrite+0x429/0x520 [ 185.373051] ? print_bad_pte+0x5f0/0x5f0 [ 185.377202] ? pud_val+0x88/0x100 [ 185.380726] ? find_held_lock+0x36/0x1c0 [ 185.384842] __handle_mm_fault+0x2a0a/0x4350 [ 185.389315] ? vmf_insert_mixed_mkwrite+0x40/0x40 [ 185.394224] ? graph_lock+0x170/0x170 [ 185.398134] ? kasan_check_read+0x11/0x20 [ 185.402348] ? lock_downgrade+0x8f0/0x8f0 [ 185.406568] ? handle_mm_fault+0x8c4/0xc80 [ 185.410849] ? handle_mm_fault+0x8c4/0xc80 [ 185.415162] ? kasan_check_read+0x11/0x20 [ 185.419382] ? rcu_is_watching+0x8c/0x150 [ 185.423637] ? __do_page_fault+0x620/0xe50 [ 185.427991] ? rcu_cleanup_dead_rnp+0x200/0x200 [ 185.432728] handle_mm_fault+0x53e/0xc80 [ 185.436868] ? __handle_mm_fault+0x4350/0x4350 [ 185.441529] ? find_vma+0x34/0x190 [ 185.445181] __do_page_fault+0x620/0xe50 [ 185.449301] ? mm_fault_error+0x380/0x380 [ 185.453523] ? entry_SYSCALL_64_after_hwframe+0x49/0xbe [ 185.458976] ? trace_hardirqs_on+0x2c0/0x2c0 [ 185.463449] do_page_fault+0xf6/0x7a4 [ 185.467331] ? vmalloc_sync_all+0x30/0x30 [ 185.471555] ? error_entry+0x70/0xd0 [ 185.475345] ? trace_hardirqs_off_caller+0xbb/0x2b0 [ 185.480436] ? trace_hardirqs_on_caller+0xc0/0x2b0 [ 185.485438] ? syscall_return_slowpath+0x5e0/0x5e0 [ 185.490457] ? trace_hardirqs_off_thunk+0x1a/0x1c [ 185.495358] ? trace_hardirqs_on_caller+0x2b0/0x2b0 [ 185.500447] ? __bpf_trace_preemptirq_template+0x30/0x30 [ 185.505969] ? prepare_exit_to_usermode+0x291/0x3b0 [ 185.511058] ? page_fault+0x8/0x30 [ 185.514689] ? trace_hardirqs_off_thunk+0x1a/0x1c [ 185.519603] ? page_fault+0x8/0x30 [ 185.523197] page_fault+0x1e/0x30 [ 185.526719] RIP: 0033:0x70b581 [ 185.529994] Code: 48 89 6c 24 10 48 8d 6c 24 10 48 8b 44 24 20 48 8b 48 08 48 8b 50 10 48 8d 58 08 48 83 fa 08 0f 8c 1e 01 00 00 48 8b 54 24 28 <88> 11 48 8b 48 08 48 8b 70 10 48 83 fe 01 0f 86 44 01 00 00 48 89 [ 185.548975] RSP: 002b:000000c4200313f0 EFLAGS: 00010212 [ 185.554410] RAX: 000000c420031508 RBX: 000000c420031510 RCX: 00007f5d5ea47000 [ 185.561733] RDX: 0000000000000543 RSI: 000000000072a460 RDI: 000000c420031348 [ 185.569107] RBP: 000000c420031400 R08: 0000000000000000 R09: 0000000000000000 [ 185.576459] R10: 0000000000949c4a R11: 0000000000000004 R12: 0000000000000000 [ 185.583771] R13: 0000000000000020 R14: 0000000000000013 R15: 000000000000000f [ 185.591163] [ 185.591163] Showing all locks held in the system: [ 185.597538] 4 locks held by kworker/u4:2/41: [ 185.602020] #0: 000000002dc51066 ((wq_completion)"writeback"){+.+.}, at: process_one_work+0xb44/0x1aa0 [ 185.611701] #1: 0000000090cba0f6 ((work_completion)(&(&wb->dwork)->work)){+.+.}, at: process_one_work+0xb9b/0x1aa0 [ 185.622389] #2: 000000004a799f2a (&fc->fs_type->s_umount_key#29){++++}, at: trylock_super+0x22/0x110 [ 185.631868] #3: 0000000007800486 (&sbi->s_journal_flag_rwsem){.+.+}, at: do_writepages+0x9a/0x1a0 [ 185.641112] 1 lock held by khungtaskd/793: [ 185.645423] #0: 0000000082e38aa8 (rcu_read_lock){....}, at: debug_show_all_locks+0xd0/0x428 [ 185.654745] 1 lock held by khugepaged/799: [ 185.659026] #0: 00000000e7f87b91 (&mm->mmap_sem){++++}, at: collapse_huge_page+0x2bf/0x2250 [ 185.668272] 1 lock held by rsyslogd/4756: [ 185.672474] #0: 0000000030d80d1a (&f->f_pos_lock){+.+.}, at: __fdget_pos+0x1bb/0x200 [ 185.680567] 2 locks held by getty/4846: [ 185.684577] #0: 000000000a2bb201 (&tty->ldisc_sem){++++}, at: ldsem_down_read+0x37/0x40 [ 185.692896] #1: 00000000027754d8 (&ldata->atomic_read_lock){+.+.}, at: n_tty_read+0x335/0x1ce0 [ 185.701843] 2 locks held by getty/4847: [ 185.705888] #0: 00000000a840976b (&tty->ldisc_sem){++++}, at: ldsem_down_read+0x37/0x40 [ 185.714221] #1: 00000000a78963a9 (&ldata->atomic_read_lock){+.+.}, at: n_tty_read+0x335/0x1ce0 [ 185.723183] 2 locks held by getty/4848: [ 185.727202] #0: 00000000b33ab2f3 (&tty->ldisc_sem){++++}, at: ldsem_down_read+0x37/0x40 [ 185.735551] #1: 000000007acda6aa (&ldata->atomic_read_lock){+.+.}, at: n_tty_read+0x335/0x1ce0 [ 185.744490] 2 locks held by getty/4849: [ 185.748538] #0: 00000000e8862c91 (&tty->ldisc_sem){++++}, at: ldsem_down_read+0x37/0x40 [ 185.756856] #1: 000000000bc10255 (&ldata->atomic_read_lock){+.+.}, at: n_tty_read+0x335/0x1ce0 [ 185.765806] 2 locks held by getty/4850: [ 185.769840] #0: 00000000850e505f (&tty->ldisc_sem){++++}, at: ldsem_down_read+0x37/0x40 [ 185.778183] #1: 00000000d32c5849 (&ldata->atomic_read_lock){+.+.}, at: n_tty_read+0x335/0x1ce0 [ 185.787128] 2 locks held by getty/4851: [ 185.791163] #0: 00000000d7dcc906 (&tty->ldisc_sem){++++}, at: ldsem_down_read+0x37/0x40 [ 185.799571] #1: 00000000ad7236e9 (&ldata->atomic_read_lock){+.+.}, at: n_tty_read+0x335/0x1ce0 [ 185.808514] 2 locks held by getty/4852: [ 185.812534] #0: 0000000074bf3088 (&tty->ldisc_sem){++++}, at: ldsem_down_read+0x37/0x40 [ 185.820870] #1: 00000000905ef677 (&ldata->atomic_read_lock){+.+.}, at: n_tty_read+0x335/0x1ce0 [ 185.829791] 1 lock held by syz-fuzzer/4868: [ 185.834185] #0: 00000000e7f87b91 (&mm->mmap_sem){++++}, at: __do_page_fault+0x389/0xe50 [ 185.842498] 1 lock held by syz-fuzzer/4872: [ 185.846877] #0: 000000003fcf37de (&rq->lock){-.-.}, at: __schedule+0x24d/0x1df0 [ 185.854519] [ 185.856201] ============================================= [ 185.856201] [ 185.863259] NMI backtrace for cpu 1 [ 185.866971] CPU: 1 PID: 793 Comm: khungtaskd Not tainted 4.19.0-rc2-next-20180905+ #57 [ 185.875036] Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 [ 185.884421] Call Trace: [ 185.887023] dump_stack+0x1c9/0x2b4 [ 185.890670] ? dump_stack_print_info.cold.2+0x52/0x52 [ 185.895865] ? vprintk_default+0x28/0x30 [ 185.899945] ? lapic_can_unplug_cpu.cold.30+0x3f/0x3f [ 185.905162] nmi_cpu_backtrace.cold.4+0x48/0x88 [ 185.909854] ? rcu_cleanup_dead_rnp+0x200/0x200 [ 185.914546] ? lapic_can_unplug_cpu.cold.30+0x3f/0x3f [ 185.919761] nmi_trigger_cpumask_backtrace+0x1b6/0x1cd [ 185.925055] arch_trigger_cpumask_backtrace+0x14/0x20 [ 185.930257] watchdog+0xb39/0x1040 [ 185.933813] ? reset_hung_task_detector+0xd0/0xd0 [ 185.938666] ? _raw_spin_unlock_irqrestore+0x74/0xc0 [ 185.943775] ? _raw_spin_unlock_irqrestore+0x74/0xc0 [ 185.948886] ? lockdep_hardirqs_on+0x421/0x5c0 [ 185.953474] ? trace_hardirqs_on+0xbd/0x2c0 [ 185.957839] ? kasan_check_read+0x11/0x20 [ 185.962017] ? __kthread_parkme+0xd7/0x1b0 [ 185.966328] ? kasan_check_write+0x14/0x20 [ 185.970591] ? do_raw_spin_lock+0xc1/0x200 [ 185.974838] ? __kthread_parkme+0x58/0x1b0 [ 185.979098] ? __sanitizer_cov_trace_const_cmp8+0x18/0x20 [ 185.984647] ? __kthread_parkme+0x106/0x1b0 [ 185.988988] kthread+0x35a/0x420 [ 185.992363] ? reset_hung_task_detector+0xd0/0xd0 [ 185.997210] ? kthread_bind+0x40/0x40 [ 186.001016] ret_from_fork+0x3a/0x50 [ 186.004842] Sending NMI from CPU 1 to CPUs 0: [ 186.009436] NMI backtrace for cpu 0 skipped: idling at native_safe_halt+0x6/0x10 [ 186.010398] Kernel panic - not syncing: hung_task: blocked tasks [ 186.023151] CPU: 1 PID: 793 Comm: khungtaskd Not tainted 4.19.0-rc2-next-20180905+ #57 [ 186.031215] Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 [ 186.040564] Call Trace: [ 186.043157] dump_stack+0x1c9/0x2b4 [ 186.046798] ? dump_stack_print_info.cold.2+0x52/0x52 [ 186.052008] ? printk_safe_log_store+0x2f0/0x2f0 [ 186.056791] panic+0x238/0x4e7 [ 186.059996] ? add_taint.cold.5+0x16/0x16 [ 186.064184] ? __sanitizer_cov_trace_const_cmp4+0x16/0x20 [ 186.069753] ? nmi_trigger_cpumask_backtrace+0x18c/0x1cd [ 186.075205] ? printk_safe_flush+0xd7/0x130 [ 186.079553] watchdog+0xb4a/0x1040 [ 186.083110] ? reset_hung_task_detector+0xd0/0xd0 [ 186.087977] ? _raw_spin_unlock_irqrestore+0x74/0xc0 [ 186.093099] ? _raw_spin_unlock_irqrestore+0x74/0xc0 [ 186.098214] ? lockdep_hardirqs_on+0x421/0x5c0 [ 186.102817] ? trace_hardirqs_on+0xbd/0x2c0 [ 186.107144] ? kasan_check_read+0x11/0x20 [ 186.111304] ? __kthread_parkme+0xd7/0x1b0 [ 186.115553] ? kasan_check_write+0x14/0x20 [ 186.119807] ? do_raw_spin_lock+0xc1/0x200 [ 186.124070] ? __kthread_parkme+0x58/0x1b0 [ 186.128327] ? __sanitizer_cov_trace_const_cmp8+0x18/0x20 [ 186.133864] ? __kthread_parkme+0x106/0x1b0 [ 186.138211] kthread+0x35a/0x420 [ 186.141603] ? reset_hung_task_detector+0xd0/0xd0 [ 186.146485] ? kthread_bind+0x40/0x40 [ 186.150296] ret_from_fork+0x3a/0x50 [ 186.154475] Dumping ftrace buffer: [ 186.158148] (ftrace buffer empty) [ 186.161852] Kernel Offset: disabled [ 186.165468] Rebooting in 86400 seconds..