[....] 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[ 22.503806] random: sshd: uninitialized urandom read (32 bytes read) [?25l[?1c7[ ok 8[?25h[?0c. Debian GNU/Linux 7 syzkaller ttyS0 syzkaller login: [ 25.546421] random: sshd: uninitialized urandom read (32 bytes read) [ 25.756792] random: sshd: uninitialized urandom read (32 bytes read) [ 26.440045] random: sshd: uninitialized urandom read (32 bytes read) Warning: Permanently added '10.128.15.198' (ECDSA) to the list of known hosts. [ 32.103010] random: sshd: uninitialized urandom read (32 bytes read) 2018/09/05 03:45:28 fuzzer started [ 33.209340] random: cc1: uninitialized urandom read (8 bytes read) 2018/09/05 03:45:30 connecting to host at 10.128.0.26:34843 2018/09/05 03:45:30 checking revisions... 2018/09/05 03:45:30 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 [ 185.228333] INFO: task syz-fuzzer:4876 blocked for more than 140 seconds. [ 185.235618] Not tainted 4.19.0-rc2-next-20180905+ #56 [ 185.241366] "echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message. [ 185.249356] syz-fuzzer D21704 4876 4871 0x00000000 [ 185.255015] Call Trace: [ 185.257638] __schedule+0x87c/0x1df0 [ 185.261539] ? __sched_text_start+0x8/0x8 [ 185.265708] ? ext4_set_page_dirty+0x254/0x340 [ 185.270373] ? graph_lock+0x170/0x170 [ 185.274270] ? print_usage_bug+0xc0/0xc0 [ 185.278372] ? __sanitizer_cov_trace_const_cmp8+0x18/0x20 [ 185.284079] ? find_held_lock+0x36/0x1c0 [ 185.288179] schedule+0xfb/0x450 [ 185.291725] ? mark_held_locks+0xc9/0x160 [ 185.295919] ? __schedule+0x1df0/0x1df0 [ 185.299910] ? _raw_spin_unlock_irq+0x27/0x70 [ 185.304448] ? _raw_spin_unlock_irq+0x27/0x70 [ 185.309033] ? lockdep_hardirqs_on+0x421/0x5c0 [ 185.313648] ? trace_hardirqs_on+0xbd/0x2c0 [ 185.318069] ? kasan_check_read+0x11/0x20 [ 185.322274] ? __lock_page+0x585/0x7a0 [ 185.326267] ? trace_hardirqs_off_caller+0x2b0/0x2b0 [ 185.331424] ? kasan_check_write+0x14/0x20 [ 185.335695] io_schedule+0x1c/0x70 [ 185.339270] __lock_page+0x5b7/0x7a0 [ 185.343032] ? __lock_page_killable+0x850/0x850 [ 185.347737] ? __sb_end_write+0xac/0xe0 [ 185.351728] ? ext4_page_mkwrite+0xa95/0x1450 [ 185.356275] ? page_cache_tree_insert+0x560/0x560 [ 185.361145] ? __lock_is_held+0xb5/0x140 [ 185.365279] ? check_same_owner+0x340/0x340 [ 185.369635] ? rcu_note_context_switch+0x680/0x680 [ 185.374600] do_page_mkwrite+0x429/0x520 [ 185.378688] ? print_bad_pte+0x5f0/0x5f0 [ 185.382779] ? pud_val+0x88/0x100 [ 185.386262] ? find_held_lock+0x36/0x1c0 [ 185.390356] __handle_mm_fault+0x2a0a/0x4350 [ 185.394784] ? vmf_insert_mixed_mkwrite+0x40/0x40 [ 185.399656] ? graph_lock+0x170/0x170 [ 185.403473] ? kasan_check_read+0x11/0x20 [ 185.407671] ? lock_downgrade+0x8f0/0x8f0 [ 185.411832] ? handle_mm_fault+0x8c4/0xc80 [ 185.416094] ? handle_mm_fault+0x8c4/0xc80 [ 185.420360] ? kasan_check_read+0x11/0x20 [ 185.424582] ? rcu_is_watching+0x8c/0x150 [ 185.428755] ? __do_page_fault+0x620/0xe50 [ 185.433037] ? rcu_cleanup_dead_rnp+0x200/0x200 [ 185.437783] handle_mm_fault+0x53e/0xc80 [ 185.441896] ? __handle_mm_fault+0x4350/0x4350 [ 185.446557] ? find_vma+0x34/0x190 [ 185.450154] __do_page_fault+0x620/0xe50 [ 185.454263] ? mm_fault_error+0x380/0x380 [ 185.458427] ? entry_SYSCALL_64_after_hwframe+0x49/0xbe [ 185.463839] ? trace_hardirqs_on+0x2c0/0x2c0 [ 185.468276] do_page_fault+0xf6/0x7a4 [ 185.472108] ? vmalloc_sync_all+0x30/0x30 [ 185.476357] ? error_entry+0x70/0xd0 [ 185.480217] ? trace_hardirqs_off_caller+0xbb/0x2b0 [ 185.485372] ? trace_hardirqs_on_caller+0xc0/0x2b0 [ 185.490330] ? syscall_return_slowpath+0x5e0/0x5e0 [ 185.495415] ? trace_hardirqs_off_thunk+0x1a/0x1c [ 185.500284] ? trace_hardirqs_on_caller+0x2b0/0x2b0 [ 185.505329] ? __bpf_trace_preemptirq_template+0x30/0x30 [ 185.510812] ? prepare_exit_to_usermode+0x3b0/0x3b0 [ 185.515856] ? prepare_exit_to_usermode+0x291/0x3b0 [ 185.520973] ? page_fault+0x8/0x30 [ 185.524546] ? trace_hardirqs_off_thunk+0x1a/0x1c [ 185.529425] ? page_fault+0x8/0x30 [ 185.532983] page_fault+0x1e/0x30 [ 185.536465] RIP: 0033:0x70b591 [ 185.539689] 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 [ 185.558618] RSP: 002b:000000c42010f3f0 EFLAGS: 00010212 [ 185.564022] RAX: 000000c42010f508 RBX: 000000c42010f510 RCX: 00007f9d22c27000 [ 185.571320] RDX: 0000000000000537 RSI: 000000000072a470 RDI: 000000c42010f348 [ 185.578610] RBP: 000000c42010f400 R08: 0000000000000000 R09: 0000000000000000 [ 185.585902] R10: 00000000009496ca R11: 0000000000000004 R12: 0000000000000000 [ 185.593258] R13: 0000000000000020 R14: 0000000000000013 R15: 000000000000000f [ 185.600645] [ 185.600645] Showing all locks held in the system: [ 185.606995] 4 locks held by kworker/u4:1/22: [ 185.611418] #0: 000000005bc28536 ((wq_completion)"writeback"){+.+.}, at: process_one_work+0xb44/0x1aa0 [ 185.621058] #1: 000000007193e1ae ((work_completion)(&(&wb->dwork)->work)){+.+.}, at: process_one_work+0xb9b/0x1aa0 [ 185.631699] #2: 0000000079a3ee6d (&fc->fs_type->s_umount_key#29){++++}, at: trylock_super+0x22/0x110 [ 185.641107] #3: 00000000f58a212d (&sbi->s_journal_flag_rwsem){.+.+}, at: do_writepages+0x9a/0x1a0 [ 185.650320] 1 lock held by khungtaskd/793: [ 185.654571] #0: 0000000020ca7c68 (rcu_read_lock){....}, at: debug_show_all_locks+0xd0/0x428 [ 185.663212] 1 lock held by khugepaged/799: [ 185.667481] #0: 00000000af3da9ce (&mm->mmap_sem){++++}, at: collapse_huge_page+0x2bf/0x2250 [ 185.676117] 1 lock held by rsyslogd/4761: [ 185.680274] #0: 00000000a67fe71d (&f->f_pos_lock){+.+.}, at: __fdget_pos+0x1bb/0x200 [ 185.688286] 2 locks held by getty/4851: [ 185.692281] #0: 00000000236449d0 (&tty->ldisc_sem){++++}, at: ldsem_down_read+0x37/0x40 [ 185.700553] #1: 000000004a997762 (&ldata->atomic_read_lock){+.+.}, at: n_tty_read+0x335/0x1ce0 [ 185.709532] 2 locks held by getty/4852: [ 185.713592] #0: 00000000d68d1a08 (&tty->ldisc_sem){++++}, at: ldsem_down_read+0x37/0x40 [ 185.721870] #1: 00000000f062cc2f (&ldata->atomic_read_lock){+.+.}, at: n_tty_read+0x335/0x1ce0 [ 185.730776] 2 locks held by getty/4853: [ 185.734770] #0: 00000000507cd5fe (&tty->ldisc_sem){++++}, at: ldsem_down_read+0x37/0x40 [ 185.743137] #1: 00000000fa59d11e (&ldata->atomic_read_lock){+.+.}, at: n_tty_read+0x335/0x1ce0 [ 185.752016] 2 locks held by getty/4854: [ 185.755997] #0: 00000000de7b4c24 (&tty->ldisc_sem){++++}, at: ldsem_down_read+0x37/0x40 [ 185.764311] #1: 00000000e3caa2a6 (&ldata->atomic_read_lock){+.+.}, at: n_tty_read+0x335/0x1ce0 [ 185.773265] 2 locks held by getty/4855: [ 185.777254] #0: 00000000e5b05f9f (&tty->ldisc_sem){++++}, at: ldsem_down_read+0x37/0x40 [ 185.785536] #1: 0000000002e17b37 (&ldata->atomic_read_lock){+.+.}, at: n_tty_read+0x335/0x1ce0 [ 185.794414] 2 locks held by getty/4856: [ 185.798402] #0: 00000000831fbb62 (&tty->ldisc_sem){++++}, at: ldsem_down_read+0x37/0x40 [ 185.806681] #1: 000000009838e2ef (&ldata->atomic_read_lock){+.+.}, at: n_tty_read+0x335/0x1ce0 [ 185.815566] 2 locks held by getty/4857: [ 185.819556] #0: 000000003038a645 (&tty->ldisc_sem){++++}, at: ldsem_down_read+0x37/0x40 [ 185.827952] #1: 00000000c1269869 (&ldata->atomic_read_lock){+.+.}, at: n_tty_read+0x335/0x1ce0 [ 185.836851] 1 lock held by syz-fuzzer/4876: [ 185.841212] #0: 00000000af3da9ce (&mm->mmap_sem){++++}, at: __do_page_fault+0x389/0xe50 [ 185.849567] [ 185.851213] ============================================= [ 185.851213] [ 185.858263] NMI backtrace for cpu 0 [ 185.861910] CPU: 0 PID: 793 Comm: khungtaskd Not tainted 4.19.0-rc2-next-20180905+ #56 [ 185.869958] Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 [ 185.879298] Call Trace: [ 185.881873] dump_stack+0x1c9/0x2b4 [ 185.885488] ? dump_stack_print_info.cold.2+0x52/0x52 [ 185.890670] ? vprintk_default+0x28/0x30 [ 185.894913] ? lapic_can_unplug_cpu.cold.30+0x3f/0x3f [ 185.900091] nmi_cpu_backtrace.cold.4+0x48/0x88 [ 185.904749] ? rcu_cleanup_dead_rnp+0x200/0x200 [ 185.909407] ? lapic_can_unplug_cpu.cold.30+0x3f/0x3f [ 185.914584] nmi_trigger_cpumask_backtrace+0x1b6/0x1cd [ 185.919849] arch_trigger_cpumask_backtrace+0x14/0x20 [ 185.925066] watchdog+0xb39/0x1040 [ 185.928608] ? reset_hung_task_detector+0xd0/0xd0 [ 185.933446] ? _raw_spin_unlock_irqrestore+0x74/0xc0 [ 185.938533] ? _raw_spin_unlock_irqrestore+0x74/0xc0 [ 185.943626] ? lockdep_hardirqs_on+0x421/0x5c0 [ 185.948197] ? trace_hardirqs_on+0xbd/0x2c0 [ 185.952505] ? kasan_check_read+0x11/0x20 [ 185.956686] ? __kthread_parkme+0xd7/0x1b0 [ 185.961003] ? kasan_check_write+0x14/0x20 [ 185.965227] ? do_raw_spin_lock+0xc1/0x200 [ 185.969449] ? __kthread_parkme+0x58/0x1b0 [ 185.973738] ? __sanitizer_cov_trace_const_cmp8+0x18/0x20 [ 185.979321] ? __kthread_parkme+0x106/0x1b0 [ 185.983634] kthread+0x35a/0x420 [ 185.986983] ? reset_hung_task_detector+0xd0/0xd0 [ 185.991805] ? kthread_bind+0x40/0x40 [ 185.995594] ret_from_fork+0x3a/0x50 [ 185.999402] Sending NMI from CPU 0 to CPUs 1: [ 186.004212] NMI backtrace for cpu 1 [ 186.004218] CPU: 1 PID: 0 Comm: swapper/1 Not tainted 4.19.0-rc2-next-20180905+ #56 [ 186.004222] Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 [ 186.004225] RIP: 0010:write_comp_data+0x22/0x70 [ 186.004233] Code: e4 b9 ca ff 90 90 90 90 55 65 4c 8b 04 25 40 ee 01 00 65 8b 05 2f 44 86 7e 48 89 e5 a9 00 01 1f 00 75 51 41 8b 80 88 12 00 00 <83> f8 03 75 45 49 8b 80 90 12 00 00 45 8b 80 8c 12 00 00 4c 8b 08 [ 186.004236] RSP: 0018:ffff8801d9f1fb10 EFLAGS: 00000046 [ 186.004242] RAX: 0000000000000000 RBX: 0000000000000000 RCX: ffffffff816df180 [ 186.004246] RDX: 0000000000000000 RSI: 0000000000000000 RDI: 0000000000000001 [ 186.004250] RBP: ffff8801d9f1fb10 R08: ffff8801d9f0e380 R09: 0000000000000000 [ 186.004253] R10: 0000000000000003 R11: 0000000000000000 R12: ffff8801d9f1fb80 [ 186.004257] R13: 0000000000021f3e R14: 0000002b4d7800be R15: 00000000fffe3d07 [ 186.004261] FS: 0000000000000000(0000) GS:ffff8801db100000(0000) knlGS:0000000000000000 [ 186.004264] CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 [ 186.004268] CR2: ffffffffff600400 CR3: 00000001b91c2000 CR4: 00000000001406e0 [ 186.004269] Call Trace: [ 186.004272] __sanitizer_cov_trace_const_cmp1+0x1a/0x20 [ 186.004275] tick_nohz_next_event+0x5e0/0x8a0 [ 186.004278] ? __tick_nohz_idle_restart_tick+0x3c0/0x3c0 [ 186.004280] ? rcu_idle_exit+0x345/0x430 [ 186.004282] ? rcu_idle_exit+0x345/0x430 [ 186.004285] ? lockdep_hardirqs_on+0x421/0x5c0 [ 186.004287] ? do_idle+0x2d6/0x580 [ 186.004290] ? __sanitizer_cov_trace_const_cmp2+0x18/0x20 [ 186.004293] tick_nohz_idle_stop_tick+0x633/0xcb0 [ 186.004295] ? tick_nohz_tick_stopped_cpu+0x80/0x80 [ 186.004298] ? tsc_verify_tsc_adjust+0x109/0x380 [ 186.004301] ? trace_hardirqs_off+0xb8/0x2b0 [ 186.004303] ? trace_hardirqs_off_caller+0x2b0/0x2b0 [ 186.004306] ? mark_tsc_async_resets+0x20/0x20 [ 186.004308] ? trace_hardirqs_on+0x2c0/0x2c0 [ 186.004311] ? __tick_nohz_idle_restart_tick+0x28c/0x3c0 [ 186.004314] ? __sanitizer_cov_trace_const_cmp4+0x16/0x20 [ 186.004316] do_idle+0x3a0/0x580 [ 186.004319] ? retint_kernel+0x10/0x10 [ 186.004321] ? arch_cpu_idle_exit+0x70/0x70 [ 186.004324] cpu_startup_entry+0x10c/0x120 [ 186.004326] ? cpu_in_idle+0x20/0x20 [ 186.004328] start_secondary+0x433/0x5d0 [ 186.004331] ? set_cpu_sibling_map+0x18b0/0x18b0 [ 186.004333] secondary_startup_64+0xa4/0xb0 [ 186.004934] Kernel panic - not syncing: hung_task: blocked tasks [ 186.234206] CPU: 0 PID: 793 Comm: khungtaskd Not tainted 4.19.0-rc2-next-20180905+ #56 [ 186.242254] Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 [ 186.251754] Call Trace: [ 186.254329] dump_stack+0x1c9/0x2b4 [ 186.257938] ? dump_stack_print_info.cold.2+0x52/0x52 [ 186.263184] ? printk_safe_log_store+0x2f0/0x2f0 [ 186.267956] panic+0x238/0x4e7 [ 186.271133] ? add_taint.cold.5+0x16/0x16 [ 186.275282] ? __sanitizer_cov_trace_const_cmp4+0x16/0x20 [ 186.280803] ? nmi_trigger_cpumask_backtrace+0x18c/0x1cd [ 186.286235] ? printk_safe_flush+0xd7/0x130 [ 186.290548] watchdog+0xb4a/0x1040 [ 186.294084] ? reset_hung_task_detector+0xd0/0xd0 [ 186.298917] ? _raw_spin_unlock_irqrestore+0x74/0xc0 [ 186.304006] ? _raw_spin_unlock_irqrestore+0x74/0xc0 [ 186.309133] ? lockdep_hardirqs_on+0x421/0x5c0 [ 186.313702] ? trace_hardirqs_on+0xbd/0x2c0 [ 186.318063] ? kasan_check_read+0x11/0x20 [ 186.322204] ? __kthread_parkme+0xd7/0x1b0 [ 186.326426] ? kasan_check_write+0x14/0x20 [ 186.330646] ? do_raw_spin_lock+0xc1/0x200 [ 186.334860] ? __kthread_parkme+0x58/0x1b0 [ 186.339094] ? __sanitizer_cov_trace_const_cmp8+0x18/0x20 [ 186.344619] ? __kthread_parkme+0x106/0x1b0 [ 186.348923] kthread+0x35a/0x420 [ 186.352272] ? reset_hung_task_detector+0xd0/0xd0 [ 186.357113] ? kthread_bind+0x40/0x40 [ 186.360910] ret_from_fork+0x3a/0x50 [ 186.365093] Dumping ftrace buffer: [ 186.368677] (ftrace buffer empty) [ 186.372488] Kernel Offset: disabled [ 186.376104] Rebooting in 86400 seconds..