[....] Starting periodic command scheduler: cron[?25l[?1c7[ ok 8[?25h[?0c. [....] Starting OpenBSD Secure Shell server: sshd[ 19.309129] random: sshd: uninitialized urandom read (32 bytes read) [?25l[?1c7[ ok 8[?25h[?0c. Debian GNU/Linux 7 syzkaller ttyS0 syzkaller login: [ 22.835387] random: sshd: uninitialized urandom read (32 bytes read) [ 23.072792] random: sshd: uninitialized urandom read (32 bytes read) [ 23.800449] random: sshd: uninitialized urandom read (32 bytes read) [ 316.122817] random: sshd: uninitialized urandom read (32 bytes read) Warning: Permanently added '10.128.0.30' (ECDSA) to the list of known hosts. [ 321.509292] random: sshd: uninitialized urandom read (32 bytes read) executing program executing program [ 446.605022] INFO: rcu_sched self-detected stall on CPU [ 446.610384] 0-....: (124998 ticks this GP) idle=45e/1/4611686018427387906 softirq=9820/9820 fqs=31227 [ 446.619982] (t=125000 jiffies g=4939 c=4938 q=43) [ 446.625019] NMI backtrace for cpu 0 [ 446.628635] CPU: 0 PID: 4515 Comm: syz-executor699 Not tainted 4.17.0-rc2+ #20 [ 446.635971] Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 [ 446.645375] Call Trace: [ 446.647950] [ 446.650216] dump_stack+0x1b9/0x294 [ 446.653856] ? dump_stack_print_info.cold.2+0x52/0x52 [ 446.659063] ? lock_release+0xa10/0xa10 [ 446.663033] nmi_cpu_backtrace.cold.4+0x19/0xce [ 446.667699] ? lapic_can_unplug_cpu.cold.26+0x3f/0x3f [ 446.672869] nmi_trigger_cpumask_backtrace+0x151/0x192 [ 446.678137] arch_trigger_cpumask_backtrace+0x14/0x20 [ 446.683322] rcu_dump_cpu_stacks+0x175/0x1c2 [ 446.687722] ? __sanitizer_cov_trace_cmp8+0x18/0x20 [ 446.692734] check_cpu_stall.isra.61.cold.80+0x36c/0x59a [ 446.698168] ? print_other_cpu_stall+0x4a0/0x4a0 [ 446.702909] ? debug_check_no_locks_freed+0x310/0x310 [ 446.708077] ? find_held_lock+0x36/0x1c0 [ 446.712133] ? lock_downgrade+0x8e0/0x8e0 [ 446.716261] ? lock_release+0xa10/0xa10 [ 446.720217] ? graph_lock+0x170/0x170 [ 446.724001] ? graph_lock+0x170/0x170 [ 446.727796] ? graph_lock+0x170/0x170 [ 446.731586] ? __sanitizer_cov_trace_const_cmp4+0x16/0x20 [ 446.737123] ? pvclock_gtod_notify+0x2db/0x3c0 [ 446.741688] ? graph_lock+0x170/0x170 [ 446.745474] ? graph_lock+0x170/0x170 [ 446.749271] ? __lock_is_held+0xb5/0x140 [ 446.753323] rcu_check_callbacks+0x21b/0xad0 [ 446.757713] ? rcu_cpu_stall_reset+0x210/0x210 [ 446.762286] ? trace_hardirqs_off+0xd/0x10 [ 446.766527] ? raise_softirq+0x1b2/0x450 [ 446.770569] ? raise_softirq_irqoff+0x310/0x310 [ 446.775231] ? account_guest_time+0x3d0/0x3d0 [ 446.779716] ? __sanitizer_cov_trace_const_cmp1+0x1a/0x20 [ 446.785246] ? hrtimer_run_queues+0x70/0x300 [ 446.789637] ? run_local_timers+0x168/0x1d0 [ 446.793943] ? timer_clear_idle+0x50/0x50 [ 446.798085] ? account_system_time+0x7f/0xb0 [ 446.802482] ? account_process_tick+0x76/0x240 [ 446.807048] update_process_times+0x2d/0x70 [ 446.811358] tick_sched_handle+0x9f/0x180 [ 446.815486] tick_sched_timer+0x45/0x130 [ 446.819529] __hrtimer_run_queues+0x3e3/0x10a0 [ 446.824098] ? tick_sched_do_timer+0x1a0/0x1a0 [ 446.828664] ? hrtimer_start_range_ns+0xd10/0xd10 [ 446.833501] ? pvclock_read_flags+0x160/0x160 [ 446.837981] ? kvm_clock_read+0x25/0x30 [ 446.841937] ? kvm_clock_read+0x25/0x30 [ 446.845892] ? __sanitizer_cov_trace_cmp4+0x16/0x20 [ 446.850897] ? ktime_get_update_offsets_now+0x3a6/0x570 [ 446.856243] ? do_timer+0x50/0x50 [ 446.859679] ? rcu_nmi_exit+0xd7/0x2b0 [ 446.863561] ? do_raw_spin_lock+0xc1/0x200 [ 446.867778] hrtimer_interrupt+0x286/0x650 [ 446.872064] smp_apic_timer_interrupt+0x15d/0x710 [ 446.876902] ? smp_call_function_single_interrupt+0x650/0x650 [ 446.882777] ? _raw_spin_lock+0x32/0x40 [ 446.886736] ? _raw_spin_unlock+0x22/0x30 [ 446.890865] ? handle_edge_irq+0x330/0x870 [ 446.895084] ? task_prio+0x50/0x50 [ 446.898650] ? trace_hardirqs_off_thunk+0x1a/0x1c [ 446.903489] apic_timer_interrupt+0xf/0x20 [ 446.907699] [ 446.909939] RIP: 0010:lo_ioctl+0x1bb4/0x2130 [ 446.914329] RSP: 0018:ffff8801b37d7948 EFLAGS: 00000293 ORIG_RAX: ffffffffffffff13 [ 446.922022] RAX: 0000000000000000 RBX: ffff8801d2930d80 RCX: ffffffff84b2b784 [ 446.929283] RDX: 0000000000000007 RSI: 0000000000000007 RDI: 0000000000000005 [ 446.936532] RBP: ffff8801b37d79c0 R08: ffff8801b2d52500 R09: ffffed003b5c46c2 [ 446.943779] R10: 0000000000000003 R11: 0000000000000001 R12: 0000000000000000 [ 446.951032] R13: ffff8801d4ff7418 R14: ffff8801b70936e0 R15: ffff8801b7093600 [ 446.958290] ? lo_ioctl+0x1bb4/0x2130 [ 446.962078] ? lo_ioctl+0x1bb4/0x2130 [ 446.965876] ? is_bpf_text_address+0xd7/0x170 [ 446.970363] ? lo_rw_aio_complete+0x430/0x430 [ 446.974890] blkdev_ioctl+0x9b6/0x2020 [ 446.978773] ? __save_stack_trace+0x7e/0xd0 [ 446.983081] ? blkpg_ioctl+0xc40/0xc40 [ 446.986987] ? save_stack+0xa9/0xd0 [ 446.990605] ? save_stack+0x43/0xd0 [ 446.994214] ? __kasan_slab_free+0x11a/0x170 [ 446.998602] ? kasan_slab_free+0xe/0x10 [ 447.002554] ? kmem_cache_free+0x86/0x2d0 [ 447.006695] ? putname+0xf2/0x130 [ 447.010138] ? do_sys_open+0x554/0x740 [ 447.014005] ? __x64_sys_open+0x7e/0xc0 [ 447.017971] ? do_syscall_64+0x1b1/0x800 [ 447.022021] ? entry_SYSCALL_64_after_hwframe+0x49/0xbe [ 447.027385] ? kasan_check_read+0x11/0x20 [ 447.031514] ? do_raw_spin_unlock+0x9e/0x2e0 [ 447.035904] ? do_raw_spin_trylock+0x1b0/0x1b0 [ 447.040465] ? kasan_check_write+0x14/0x20 [ 447.044679] ? do_raw_spin_lock+0xc1/0x200 [ 447.048895] ? trace_hardirqs_off+0xd/0x10 [ 447.053109] ? _raw_spin_unlock_irqrestore+0x63/0xc0 [ 447.058210] block_ioctl+0xee/0x130 [ 447.061819] ? blkdev_fallocate+0x400/0x400 [ 447.066122] do_vfs_ioctl+0x1cf/0x16a0 [ 447.069989] ? rcu_pm_notify+0xc0/0xc0 [ 447.073860] ? ioctl_preallocate+0x2e0/0x2e0 [ 447.078255] ? fget_raw+0x20/0x20 [ 447.081687] ? putname+0xf2/0x130 [ 447.085127] ? rcu_read_lock_sched_held+0x108/0x120 [ 447.090121] ? kmem_cache_free+0x25c/0x2d0 [ 447.094338] ? putname+0xf7/0x130 [ 447.097809] ? security_file_ioctl+0x94/0xc0 [ 447.102203] ksys_ioctl+0xa9/0xd0 [ 447.105647] __x64_sys_ioctl+0x73/0xb0 [ 447.109519] do_syscall_64+0x1b1/0x800 [ 447.113390] ? syscall_return_slowpath+0x5c0/0x5c0 [ 447.118299] ? syscall_return_slowpath+0x30f/0x5c0 [ 447.123214] ? entry_SYSCALL_64_after_hwframe+0x59/0xbe [ 447.128562] ? trace_hardirqs_off_thunk+0x1a/0x1c [ 447.133394] entry_SYSCALL_64_after_hwframe+0x49/0xbe [ 447.138581] RIP: 0033:0x443e59 [ 447.141751] RSP: 002b:00007fff93b51bd8 EFLAGS: 00000217 ORIG_RAX: 0000000000000010 [ 447.149439] RAX: ffffffffffffffda RBX: 6f6f6c2f7665642f RCX: 0000000000443e59 [ 447.156688] RDX: 0000000000000007 RSI: 0000000000004c00 RDI: 0000000000000008 [ 447.163936] RBP: 702f74656e2f666c R08: 00000000004002e0 R09: 00000000004002e0 [ 447.171186] R10: 0000000000000000 R11: 0000000000000217 R12: 65732f636f72702f [ 447.178434] R13: 0000000000401b90 R14: 0000000000000000 R15: 0000000000000000