[....] Starting periodic command scheduler: cron[?25l[?1c7[ ok 8[?25h[?0c. [....] Starting OpenBSD Secure Shell server: sshd[ 19.554757] random: sshd: uninitialized urandom read (32 bytes read) [?25l[?1c7[ ok 8[?25h[?0c. Debian GNU/Linux 7 syzkaller ttyS0 syzkaller login: [ 23.465710] random: sshd: uninitialized urandom read (32 bytes read) [ 23.806534] random: sshd: uninitialized urandom read (32 bytes read) [ 24.533935] random: sshd: uninitialized urandom read (32 bytes read) [ 306.272696] random: sshd: uninitialized urandom read (32 bytes read) Warning: Permanently added '10.128.10.28' (ECDSA) to the list of known hosts. [ 312.118281] random: sshd: uninitialized urandom read (32 bytes read) executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program [ 437.221022] INFO: rcu_sched self-detected stall on CPU [ 437.226407] 1-....: (124999 ticks this GP) idle=262/1/4611686018427387906 softirq=10375/10378 fqs=31238 [ 437.236189] (t=125000 jiffies g=5043 c=5042 q=11) [ 437.241194] NMI backtrace for cpu 1 [ 437.244835] CPU: 1 PID: 4508 Comm: syz-executor268 Not tainted 4.17.0-rc2+ #22 [ 437.252185] Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 [ 437.261578] Call Trace: [ 437.264153] [ 437.266398] dump_stack+0x1b9/0x294 [ 437.270013] ? dump_stack_print_info.cold.2+0x52/0x52 [ 437.275306] ? lock_release+0xa10/0xa10 [ 437.279266] nmi_cpu_backtrace.cold.4+0x19/0xce [ 437.283966] ? lapic_can_unplug_cpu.cold.26+0x3f/0x3f [ 437.289139] nmi_trigger_cpumask_backtrace+0x151/0x192 [ 437.294402] arch_trigger_cpumask_backtrace+0x14/0x20 [ 437.299626] rcu_dump_cpu_stacks+0x175/0x1c2 [ 437.304046] ? __sanitizer_cov_trace_cmp8+0x18/0x20 [ 437.309055] check_cpu_stall.isra.61.cold.80+0x36c/0x59a [ 437.314489] ? print_other_cpu_stall+0x4a0/0x4a0 [ 437.319233] ? debug_check_no_locks_freed+0x310/0x310 [ 437.324413] ? find_held_lock+0x36/0x1c0 [ 437.328465] ? lock_downgrade+0x8e0/0x8e0 [ 437.332601] ? lock_release+0xa10/0xa10 [ 437.336579] ? graph_lock+0x170/0x170 [ 437.340367] ? graph_lock+0x170/0x170 [ 437.344160] ? graph_lock+0x170/0x170 [ 437.347970] ? __sanitizer_cov_trace_const_cmp4+0x16/0x20 [ 437.353557] ? pvclock_gtod_notify+0x2db/0x3c0 [ 437.358122] ? graph_lock+0x170/0x170 [ 437.361903] ? graph_lock+0x170/0x170 [ 437.365691] ? __lock_is_held+0xb5/0x140 [ 437.369739] rcu_check_callbacks+0x21b/0xad0 [ 437.374145] ? rcu_cpu_stall_reset+0x210/0x210 [ 437.378714] ? trace_hardirqs_off+0xd/0x10 [ 437.382998] ? raise_softirq+0x1b2/0x450 [ 437.387061] ? raise_softirq_irqoff+0x310/0x310 [ 437.391762] ? account_guest_time+0x3d0/0x3d0 [ 437.396263] ? __sanitizer_cov_trace_const_cmp1+0x1a/0x20 [ 437.401838] ? hrtimer_run_queues+0x70/0x300 [ 437.406237] ? run_local_timers+0x168/0x1d0 [ 437.410542] ? timer_clear_idle+0x50/0x50 [ 437.414683] ? account_system_time+0x7f/0xb0 [ 437.419073] ? account_process_tick+0x76/0x240 [ 437.423646] update_process_times+0x2d/0x70 [ 437.427996] tick_sched_handle+0x9f/0x180 [ 437.432132] tick_sched_timer+0x45/0x130 [ 437.436182] __hrtimer_run_queues+0x3e3/0x10a0 [ 437.440747] ? tick_sched_do_timer+0x1a0/0x1a0 [ 437.445309] ? hrtimer_start_range_ns+0xd10/0xd10 [ 437.450166] ? pvclock_read_flags+0x160/0x160 [ 437.454644] ? __local_bh_enable+0xef/0x130 [ 437.458950] ? kvm_clock_read+0x25/0x30 [ 437.462913] ? __sanitizer_cov_trace_cmp4+0x16/0x20 [ 437.467914] ? ktime_get_update_offsets_now+0x3a6/0x570 [ 437.473265] ? do_timer+0x50/0x50 [ 437.476698] ? rcu_nmi_exit+0xd7/0x2b0 [ 437.480620] ? do_raw_spin_lock+0xc1/0x200 [ 437.484841] hrtimer_interrupt+0x286/0x650 [ 437.489115] smp_apic_timer_interrupt+0x15d/0x710 [ 437.493943] ? smp_call_function_single_interrupt+0x650/0x650 [ 437.499829] ? _raw_spin_lock+0x32/0x40 [ 437.503813] ? _raw_spin_unlock+0x22/0x30 [ 437.507941] ? handle_edge_irq+0x330/0x870 [ 437.512157] ? task_prio+0x50/0x50 [ 437.515720] ? trace_hardirqs_off_thunk+0x1a/0x1c [ 437.520560] apic_timer_interrupt+0xf/0x20 [ 437.524771] [ 437.527069] RIP: 0010:echo_char+0x1d7/0x2e0 [ 437.531371] RSP: 0018:ffff8801acfaf718 EFLAGS: 00000a02 ORIG_RAX: ffffffffffffff13 [ 437.539060] RAX: 0000000000000000 RBX: ffffc900021fc000 RCX: ffffffff8397a3dc [ 437.546312] RDX: ffffc900021fd7d9 RSI: ffffffff8397a43f RDI: ffffc900021fd7d9 [ 437.553606] RBP: ffff8801acfaf748 R08: ffff8801d911a100 R09: 0000000000000001 [ 437.560853] R10: ffff8801d911a960 R11: ffff8801d911a100 R12: 0000000000000000 [ 437.568103] R13: 0000000000000008 R14: 0000000141ce0578 R15: 0000000000000579 [ 437.575365] ? echo_char+0x14c/0x2e0 [ 437.579060] ? echo_char+0x1af/0x2e0 [ 437.582756] ? echo_char+0x1af/0x2e0 [ 437.586452] n_tty_receive_char_special+0x13b3/0x31c0 [ 437.591625] ? down_read+0xaf/0x1b0 [ 437.595233] ? n_tty_receive_buf_common+0xe3/0x2c50 [ 437.600231] ? __down_interruptible+0x6e0/0x6e0 [ 437.604881] ? n_tty_open+0x460/0x460 [ 437.608676] n_tty_receive_buf_common+0x20ca/0x2c50 [ 437.613681] ? n_tty_receive_char_lnext+0x710/0x710 [ 437.618682] ? rcu_note_context_switch+0x710/0x710 [ 437.623604] ? __sanitizer_cov_trace_const_cmp4+0x16/0x20 [ 437.629130] n_tty_receive_buf+0x30/0x40 [ 437.633172] tty_ioctl+0x7e7/0x1870 [ 437.636779] ? tty_vhangup+0x30/0x30 [ 437.640568] ? save_stack+0x43/0xd0 [ 437.644180] ? __kasan_slab_free+0x11a/0x170 [ 437.648567] ? kasan_slab_free+0xe/0x10 [ 437.652521] ? kmem_cache_free+0x86/0x2d0 [ 437.656692] ? putname+0xf2/0x130 [ 437.660145] ? do_sys_open+0x554/0x740 [ 437.664020] ? __x64_sys_open+0x7e/0xc0 [ 437.667985] ? do_syscall_64+0x120/0x800 [ 437.672035] ? entry_SYSCALL_64_after_hwframe+0x49/0xbe [ 437.677396] ? kasan_check_read+0x11/0x20 [ 437.681529] ? do_raw_spin_unlock+0x9e/0x2e0 [ 437.685917] ? do_raw_spin_trylock+0x1b0/0x1b0 [ 437.690479] ? kasan_check_write+0x14/0x20 [ 437.694699] ? do_raw_spin_lock+0xc1/0x200 [ 437.699604] ? trace_hardirqs_off+0xd/0x10 [ 437.703833] ? _raw_spin_unlock_irqrestore+0x63/0xc0 [ 437.708998] ? debug_check_no_obj_freed+0x2ff/0x584 [ 437.714007] ? tty_vhangup+0x30/0x30 [ 437.717713] do_vfs_ioctl+0x1cf/0x16a0 [ 437.721582] ? rcu_pm_notify+0xc0/0xc0 [ 437.725463] ? ioctl_preallocate+0x2e0/0x2e0 [ 437.729910] ? fget_raw+0x20/0x20 [ 437.733344] ? putname+0xf2/0x130 [ 437.736786] ? rcu_read_lock_sched_held+0x108/0x120 [ 437.741790] ? kmem_cache_free+0x25c/0x2d0 [ 437.746094] ? putname+0xf7/0x130 [ 437.749618] ? security_file_ioctl+0x94/0xc0 [ 437.754034] ksys_ioctl+0xa9/0xd0 [ 437.757484] __x64_sys_ioctl+0x73/0xb0 [ 437.761359] do_syscall_64+0x1b1/0x800 [ 437.765229] ? syscall_return_slowpath+0x5c0/0x5c0 [ 437.770140] ? syscall_return_slowpath+0x30f/0x5c0 [ 437.775141] ? entry_SYSCALL_64_after_hwframe+0x59/0xbe [ 437.780505] ? trace_hardirqs_off_thunk+0x1a/0x1c [ 437.785685] entry_SYSCALL_64_after_hwframe+0x49/0xbe [ 437.790851] RIP: 0033:0x440209 [ 437.794024] RSP: 002b:00007ffe6293c578 EFLAGS: 00000213 ORIG_RAX: 0000000000000010 [ 437.801722] RAX: ffffffffffffffda RBX: 00000000200006c0 RCX: 0000000000440209 [ 437.808969] RDX: 00000000200000c0 RSI: 0000000000005412 RDI: 0000000000000100 [ 437.816229] RBP: 6d74702f7665642f R08: 000000000000000c R09: 00007ffe6293c5f0 [ 437.823492] R10: 0000000000000000 R11: 0000000000000213 R12: 0000000000401a70 [ 437.830759] R13: 0000000000401b00 R14: 0000000000000000 R15: 0000000000000000