[....] Starting periodic command scheduler: cron[?25l[?1c7[ ok 8[?25h[?0c. [....] Starting OpenBSD Secure Shell server: sshd[ 19.702564] random: sshd: uninitialized urandom read (32 bytes read) [?25l[?1c7[ ok 8[?25h[?0c. Debian GNU/Linux 7 syzkaller ttyS0 syzkaller login: [ 22.978845] random: sshd: uninitialized urandom read (32 bytes read) [ 23.255601] random: sshd: uninitialized urandom read (32 bytes read) [ 24.007865] random: sshd: uninitialized urandom read (32 bytes read) [ 1033.448729] random: sshd: uninitialized urandom read (32 bytes read) Warning: Permanently added '10.128.0.4' (ECDSA) to the list of known hosts. [ 1038.921702] random: sshd: uninitialized urandom read (32 bytes read) executing program executing program executing program executing program executing program executing program [ 1039.024292] EXT4-fs (sda1): re-mounted. Opts: [ 1039.041073] EXT4-fs (sda1): re-mounted. Opts: executing program [ 1039.066807] EXT4-fs (sda1): re-mounted. Opts: executing program [ 1039.091728] EXT4-fs (sda1): re-mounted. Opts: [ 1039.116987] EXT4-fs (sda1): re-mounted. Opts: [ 1039.121782] EXT4-fs (sda1): re-mounted. Opts: [ 1039.146578] EXT4-fs (sda1): re-mounted. Opts: executing program executing program executing program [ 1039.168131] EXT4-fs (sda1): re-mounted. Opts: executing program executing program executing program executing program [ 1039.227484] EXT4-fs (sda1): re-mounted. Opts: [ 1039.232857] EXT4-fs (sda1): re-mounted. Opts: 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 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 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 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 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 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 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 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 [ 1044.049329] EXT4-fs: 301 callbacks suppressed [ 1044.049339] EXT4-fs (sda1): re-mounted. Opts: executing program executing program executing program executing program [ 1044.111753] EXT4-fs (sda1): re-mounted. Opts: [ 1044.154467] EXT4-fs (sda1): re-mounted. Opts: [ 1044.163701] EXT4-fs (sda1): re-mounted. Opts: [ 1044.180814] EXT4-fs (sda1): re-mounted. Opts: [ 1044.191610] EXT4-fs (sda1): re-mounted. Opts: [ 1044.197861] EXT4-fs (sda1): re-mounted. Opts: executing program [ 1044.202973] EXT4-fs (sda1): re-mounted. Opts: executing program executing program executing program [ 1044.292738] EXT4-fs (sda1): re-mounted. Opts: executing program executing program executing program executing program [ 1044.314646] EXT4-fs (sda1): re-mounted. Opts: 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 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 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 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 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 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 [ 1049.082349] EXT4-fs: 223 callbacks suppressed [ 1049.082358] EXT4-fs (sda1): re-mounted. Opts: [ 1049.094152] EXT4-fs (sda1): re-mounted. Opts: [ 1049.099213] EXT4-fs (sda1): re-mounted. Opts: [ 1049.104203] EXT4-fs (sda1): re-mounted. Opts: [ 1049.151481] EXT4-fs (sda1): re-mounted. Opts: executing program [ 1049.173846] EXT4-fs (sda1): re-mounted. Opts: executing program executing program executing program executing program executing program executing program [ 1049.249591] EXT4-fs (sda1): re-mounted. Opts: [ 1049.258789] EXT4-fs (sda1): re-mounted. Opts: [ 1049.263907] EXT4-fs (sda1): re-mounted. Opts: executing program [ 1049.294476] EXT4-fs (sda1): re-mounted. Opts: executing program executing program [ 1049.356827] random: crng init done 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 executing program executing program executing program executing program executing program executing program executing program executing program executing program [ 1175.086022] INFO: rcu_sched self-detected stall on CPU [ 1175.091444] 0-...!: (124999 ticks this GP) idle=e9e/1/4611686018427387906 softirq=20143/20143 fqs=0 [ 1175.100917] (t=125000 jiffies g=9955 c=9954 q=7) [ 1175.105859] rcu_sched kthread starved for 125000 jiffies! g9955 c9954 f0x0 RCU_GP_WAIT_FQS(3) ->state=0x0 ->cpu=0 [ 1175.116240] RCU grace-period kthread stack dump: [ 1175.120981] rcu_sched R running task 23896 9 2 0x80000000 [ 1175.128258] Call Trace: [ 1175.130928] __schedule+0x801/0x1e30 [ 1175.134695] ? trace_hardirqs_on_caller+0x421/0x5c0 [ 1175.139714] ? __sched_text_start+0x8/0x8 [ 1175.143859] ? _cond_resched+0x14/0x30 [ 1175.147794] ? rcu_gp_init+0x83f/0x1060 [ 1175.151778] ? add_timer_on+0xa50/0xa50 [ 1175.155748] ? find_held_lock+0x36/0x1c0 [ 1175.159811] ? lock_downgrade+0x8e0/0x8e0 [ 1175.163955] ? rcu_accelerate_cbs+0xc0/0xa60 [ 1175.168365] schedule+0xef/0x430 [ 1175.171728] ? do_raw_spin_trylock+0x1b0/0x1b0 [ 1175.176308] ? __schedule+0x1e30/0x1e30 [ 1175.180371] ? trace_hardirqs_on_caller+0x421/0x5c0 [ 1175.185380] ? trace_hardirqs_on+0xd/0x10 [ 1175.189561] ? prepare_to_swait+0x19b/0x500 [ 1175.193881] ? __lockdep_init_map+0x105/0x590 [ 1175.198374] ? lockdep_init_map+0x9/0x10 [ 1175.202429] ? init_timer_on_stack_key+0xb7/0xe0 [ 1175.207206] schedule_timeout+0x138/0x240 [ 1175.211349] ? usleep_range+0x180/0x180 [ 1175.215318] ? __next_timer_interrupt+0x1a0/0x1a0 [ 1175.220164] rcu_gp_kthread+0x6b5/0x1940 [ 1175.224236] ? rcu_batches_completed_sched+0x10/0x10 [ 1175.229332] ? perf_trace_lock+0x521/0x900 [ 1175.233563] ? pick_next_task_fair+0x97c/0x1780 [ 1175.238226] ? graph_lock+0x170/0x170 [ 1175.242074] ? resched_curr+0x122/0x190 [ 1175.246049] ? perf_trace_lock+0x520/0x900 [ 1175.250288] ? lock_downgrade+0x8e0/0x8e0 [ 1175.254429] ? finish_task_switch+0x182/0x840 [ 1175.258995] ? kasan_check_read+0x11/0x20 [ 1175.263140] ? do_raw_spin_unlock+0x9e/0x2e0 [ 1175.267546] ? do_raw_spin_trylock+0x1b0/0x1b0 [ 1175.272177] ? compat_start_thread+0x80/0x80 [ 1175.276581] ? _raw_spin_unlock_irq+0x27/0x70 [ 1175.281073] ? trace_hardirqs_on_caller+0x421/0x5c0 [ 1175.286101] ? kasan_check_write+0x14/0x20 [ 1175.290331] ? finish_task_switch+0x28b/0x840 [ 1175.294827] ? preempt_notifier_register+0x1e0/0x1e0 [ 1175.299932] ? lock_repin_lock+0x410/0x410 [ 1175.304170] ? __schedule+0x809/0x1e30 [ 1175.308062] ? graph_lock+0x170/0x170 [ 1175.311860] ? find_held_lock+0x36/0x1c0 [ 1175.315933] ? find_held_lock+0x36/0x1c0 [ 1175.320002] ? __schedule+0x1e30/0x1e30 [ 1175.323972] ? do_raw_spin_unlock+0x9e/0x2e0 [ 1175.328375] ? do_raw_spin_trylock+0x1b0/0x1b0 [ 1175.333017] ? __sanitizer_cov_trace_const_cmp8+0x18/0x20 [ 1175.338578] ? parse_args.cold.15+0x1b3/0x1b3 [ 1175.343071] ? trace_hardirqs_on_caller+0x421/0x5c0 [ 1175.348085] ? trace_hardirqs_on+0xd/0x10 [ 1175.352237] kthread+0x345/0x410 [ 1175.355603] ? rcu_batches_completed_sched+0x10/0x10 [ 1175.360701] ? kthread_bind+0x40/0x40 [ 1175.364890] ret_from_fork+0x3a/0x50 [ 1175.368615] NMI backtrace for cpu 0 [ 1175.372274] CPU: 0 PID: 4555 Comm: syz-executor826 Not tainted 4.17.0-rc6+ #67 [ 1175.379625] Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 [ 1175.388971] Call Trace: [ 1175.391543] [ 1175.393750] dump_stack+0x1b9/0x294 [ 1175.397380] ? dump_stack_print_info.cold.2+0x52/0x52 [ 1175.402568] ? lock_release+0xa10/0xa10 [ 1175.406542] nmi_cpu_backtrace.cold.4+0x19/0xce [ 1175.411243] ? lapic_can_unplug_cpu.cold.26+0x3f/0x3f [ 1175.416428] nmi_trigger_cpumask_backtrace+0x151/0x192 [ 1175.421706] arch_trigger_cpumask_backtrace+0x14/0x20 [ 1175.426892] rcu_dump_cpu_stacks+0x175/0x1c2 [ 1175.431305] ? __sanitizer_cov_trace_cmp8+0x18/0x20 [ 1175.436328] check_cpu_stall.isra.61.cold.80+0x36c/0x59a [ 1175.441782] ? print_other_cpu_stall+0x4a0/0x4a0 [ 1175.446549] ? debug_check_no_locks_freed+0x310/0x310 [ 1175.451734] ? find_held_lock+0x36/0x1c0 [ 1175.455801] ? lock_downgrade+0x8e0/0x8e0 [ 1175.459947] ? lock_release+0xa10/0xa10 [ 1175.464179] ? graph_lock+0x170/0x170 [ 1175.467980] ? graph_lock+0x170/0x170 [ 1175.471776] ? graph_lock+0x170/0x170 [ 1175.475575] ? __sanitizer_cov_trace_const_cmp4+0x16/0x20 [ 1175.481178] ? pvclock_gtod_notify+0x2db/0x3c0 [ 1175.485755] ? graph_lock+0x170/0x170 [ 1175.489810] ? graph_lock+0x170/0x170 [ 1175.493616] ? __lock_is_held+0xb5/0x140 [ 1175.497685] rcu_check_callbacks+0x21b/0xad0 [ 1175.502095] ? rcu_cpu_stall_reset+0x210/0x210 [ 1175.506676] ? trace_hardirqs_off+0xd/0x10 [ 1175.510943] ? raise_softirq+0x1b2/0x450 [ 1175.515002] ? raise_softirq_irqoff+0x310/0x310 [ 1175.519675] ? account_guest_time+0x3d0/0x3d0 [ 1175.524168] ? __sanitizer_cov_trace_const_cmp1+0x1a/0x20 [ 1175.529727] ? hrtimer_run_queues+0x70/0x390 [ 1175.534139] ? run_local_timers+0x168/0x1d0 [ 1175.538455] ? timer_clear_idle+0x50/0x50 [ 1175.542601] ? account_system_time+0x7f/0xb0 [ 1175.547008] ? account_process_tick+0x76/0x240 [ 1175.551590] update_process_times+0x2d/0x70 [ 1175.555946] tick_sched_handle+0x9f/0x180 [ 1175.560094] tick_sched_timer+0x45/0x130 [ 1175.564153] __hrtimer_run_queues+0x3e3/0x10a0 [ 1175.568734] ? tick_sched_do_timer+0x1a0/0x1a0 [ 1175.573317] ? hrtimer_start_range_ns+0xd10/0xd10 [ 1175.578214] ? pvclock_read_flags+0x160/0x160 [ 1175.582704] ? kvm_clock_read+0x25/0x30 [ 1175.586679] ? __sanitizer_cov_trace_cmp4+0x16/0x20 [ 1175.591692] ? kvm_clock_read+0x25/0x30 [ 1175.595661] ? __sanitizer_cov_trace_cmp4+0x16/0x20 [ 1175.600678] ? ktime_get_update_offsets_now+0x3d3/0x5c0 [ 1175.606049] ? do_timer+0x50/0x50 [ 1175.609508] ? rcu_nmi_exit+0xd7/0x2b0 [ 1175.613398] ? do_raw_spin_lock+0xc1/0x200 [ 1175.617637] hrtimer_interrupt+0x2f3/0x750 [ 1175.621885] smp_apic_timer_interrupt+0x15d/0x710 [ 1175.626734] ? smp_call_function_single_interrupt+0x650/0x650 [ 1175.632613] ? _raw_spin_lock+0x32/0x40 [ 1175.636587] ? _raw_spin_unlock+0x22/0x30 [ 1175.640754] ? handle_edge_irq+0x330/0x870 [ 1175.644986] ? task_prio+0x50/0x50 [ 1175.648549] ? trace_hardirqs_off_thunk+0x1a/0x1c [ 1175.653397] apic_timer_interrupt+0xf/0x20 [ 1175.657619] [ 1175.659855] RIP: 0010:lock_acquire+0x257/0x520 [ 1175.664535] RSP: 0018:ffff8801ac7178f0 EFLAGS: 00000286 ORIG_RAX: ffffffffffffff13 [ 1175.672238] RAX: dffffc0000000000 RBX: 1ffff100358e2f23 RCX: 0000000000000000 [ 1175.679498] RDX: 1ffffffff11a31ad RSI: ffff8801d9332d78 RDI: 0000000000000286 [ 1175.686760] RBP: ffff8801ac7179e0 R08: 0000000000000008 R09: 0000000000000004 [ 1175.694026] R10: ffff8801d9332e18 R11: ffff8801d9332540 R12: ffff8801d9332540 [ 1175.701288] R13: 0000000000000002 R14: 0000000000000000 R15: 0000000000000000 [ 1175.708576] ? __sanitizer_cov_trace_const_cmp4+0x16/0x20 [ 1175.714109] ? lock_release+0xa10/0xa10 [ 1175.718079] ? kasan_check_read+0x11/0x20 [ 1175.722221] ? do_raw_spin_unlock+0x9e/0x2e0 [ 1175.726626] ? do_raw_spin_trylock+0x1b0/0x1b0 [ 1175.731206] ? kasan_check_write+0x14/0x20 [ 1175.735436] ? do_raw_spin_lock+0xc1/0x200 [ 1175.739740] d_walk+0x49b/0xc80 [ 1175.743016] ? d_walk+0x46a/0xc80 [ 1175.746472] ? d_shrink_del+0x3b0/0x3b0 [ 1175.750448] ? dget_parent+0x680/0x680 [ 1175.754333] ? shrink_dentry_list+0x5a8/0x7c0 [ 1175.758823] ? retint_kernel+0x10/0x10 [ 1175.762711] ? is_subdir+0x480/0x480 [ 1175.766422] ? shrink_dcache_parent+0x199/0x230 [ 1175.771086] ? shrink_dcache_parent+0xc7/0x230 [ 1175.775668] ? __sanitizer_cov_trace_pc+0x26/0x50 [ 1175.780512] shrink_dcache_parent+0x179/0x230 [ 1175.785006] ? path_has_submounts+0x1a0/0x1a0 [ 1175.789501] ? down_write+0x87/0x120 [ 1175.793210] ? vfs_rmdir+0xe0/0x470 [ 1175.796838] ? down_read+0x1b0/0x1b0 [ 1175.800556] ? __sanitizer_cov_trace_const_cmp4+0x16/0x20 [ 1175.806176] ? security_inode_rmdir+0xf4/0x130 [ 1175.810760] vfs_rmdir+0x202/0x470 [ 1175.814303] do_rmdir+0x523/0x610 [ 1175.817757] ? __ia32_sys_mkdir+0x80/0x80 [ 1175.821902] ? exit_to_usermode_loop+0x87/0x310 [ 1175.826571] ? __sanitizer_cov_trace_const_cmp4+0x16/0x20 [ 1175.832107] ? exit_to_usermode_loop+0x1ef/0x310 [ 1175.836862] ? do_syscall_64+0x92/0x800 [ 1175.840844] __x64_sys_rmdir+0x36/0x40 [ 1175.844730] do_syscall_64+0x1b1/0x800 [ 1175.848617] ? syscall_slow_exit_work+0x4f0/0x4f0 [ 1175.853456] ? syscall_return_slowpath+0x5c0/0x5c0 [ 1175.858391] ? syscall_return_slowpath+0x30f/0x5c0 [ 1175.863323] ? entry_SYSCALL_64_after_hwframe+0x59/0xbe [ 1175.868688] ? trace_hardirqs_off_thunk+0x1a/0x1c [ 1175.873531] entry_SYSCALL_64_after_hwframe+0x49/0xbe [ 1175.878712] RIP: 0033:0x441437 [ 1175.881892] RSP: 002b:00007ffc44f5bd88 EFLAGS: 00000207 ORIG_RAX: 0000000000000054 [ 1175.889598] RAX: ffffffffffffffda RBX: 0000000000000065 RCX: 0000000000441437 [ 1175.896862] RDX: 0000000000000000 RSI: 00000000006cd858 RDI: 00007ffc44f5ce70 [ 1175.904133] RBP: 00007ffc44f5ce70 R08: 0000000000000000 R09: 0000000000000001 [ 1175.911399] R10: 0000000000000005 R11: 0000000000000207 R12: 00000000014bd8a0 [ 1175.918662] R13: 0000000000000000 R14: 0000000000000000 R15: 0000000000000000