INIT: Entering runlevel: 2 [info] Using makefile-style concurrent boot in runlevel 2. [....] 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[?25l[?1c7[ ok 8[?25h[?0c. Debian GNU/Linux 7 syzkaller ttyS0 Warning: Permanently added '10.128.0.38' (ECDSA) to the list of known hosts. executing program syzkaller login: [ 615.392151] INFO: task syzkaller681645:4295 blocked for more than 120 seconds. [ 615.399769] Not tainted 4.16.0-rc7+ #3 [ 615.404534] "echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message. [ 615.412505] syzkaller681645 D20744 4295 4293 0x00000000 [ 615.418151] Call Trace: [ 615.420757] __schedule+0x8fb/0x1ec0 [ 615.424490] ? __sched_text_start+0x8/0x8 [ 615.428632] ? lock_release+0xa40/0xa40 [ 615.432606] ? check_same_owner+0x320/0x320 [ 615.436945] ? rcu_note_context_switch+0x710/0x710 [ 615.441887] ? __might_sleep+0x95/0x190 [ 615.445863] ? ucma_destroy_id+0x298/0x500 [ 615.450111] ? __mutex_lock+0x16f/0x1a80 [ 615.454270] ? ucma_destroy_id+0x298/0x500 [ 615.458519] ? trace_hardirqs_off+0x10/0x10 [ 615.462849] schedule+0xf5/0x430 [ 615.466225] ? mutex_lock_io_nested+0x1900/0x1900 [ 615.471074] ? __schedule+0x1ec0/0x1ec0 [ 615.475057] ? find_held_lock+0x35/0x1d0 [ 615.479120] ? wait_for_completion+0x40d/0x770 [ 615.483706] ? lock_downgrade+0x980/0x980 [ 615.487857] schedule_timeout+0x1a3/0x230 [ 615.492034] ? usleep_range+0x190/0x190 [ 615.496024] ? check_same_owner+0x320/0x320 [ 615.500352] ? node_tag_set+0xae/0x130 [ 615.504240] ? do_raw_spin_trylock+0x190/0x190 [ 615.508834] ? _raw_spin_unlock_irq+0x27/0x70 [ 615.513349] ? trace_hardirqs_on_caller+0x421/0x5c0 [ 615.518375] wait_for_completion+0x415/0x770 [ 615.522790] ? wait_for_completion+0x770/0x770 [ 615.527380] ? wait_for_completion_interruptible+0x7e0/0x7e0 [ 615.533190] ? wake_up_q+0xe0/0xe0 [ 615.536742] ucma_destroy_id+0x2f0/0x500 [ 615.540803] ? ucma_close+0x2f0/0x2f0 [ 615.544608] ? __might_sleep+0x95/0x190 [ 615.548587] ? kasan_check_write+0x14/0x20 [ 615.552827] ? _copy_from_user+0x99/0x110 [ 615.557044] ucma_write+0x2d6/0x3d0 [ 615.560665] ? ucma_close+0x2f0/0x2f0 [ 615.564491] ? ucma_close_id+0x60/0x60 [ 615.568395] ? ucma_close_id+0x60/0x60 [ 615.572287] __vfs_write+0xef/0x970 [ 615.575916] ? kernel_read+0x120/0x120 [ 615.579811] ? fsnotify+0x7b3/0x1140 [ 615.583525] ? rcu_pm_notify+0xc0/0xc0 [ 615.587429] ? security_file_permission+0x89/0x1e0 [ 615.592354] ? rw_verify_area+0xe5/0x2b0 [ 615.596414] ? __fdget_raw+0x20/0x20 [ 615.600133] vfs_write+0x189/0x510 [ 615.603727] SyS_write+0xef/0x220 [ 615.607727] ? filp_open+0x70/0x70 [ 615.611291] ? SyS_read+0x220/0x220 [ 615.614920] ? do_syscall_64+0xb7/0x940 [ 615.618900] ? SyS_read+0x220/0x220 [ 615.622525] do_syscall_64+0x281/0x940 [ 615.626408] ? __do_page_fault+0xc90/0xc90 [ 615.630636] ? trace_hardirqs_on_thunk+0x1a/0x1c [ 615.635398] ? syscall_return_slowpath+0x550/0x550 [ 615.640328] ? syscall_return_slowpath+0x2ac/0x550 [ 615.645259] ? prepare_exit_to_usermode+0x350/0x350 [ 615.650303] ? entry_SYSCALL_64_after_hwframe+0x52/0xb7 [ 615.655686] ? trace_hardirqs_off_thunk+0x1a/0x1c [ 615.660539] entry_SYSCALL_64_after_hwframe+0x42/0xb7 [ 615.665737] RIP: 0033:0x440719 [ 615.668920] RSP: 002b:00007ffc7e451f28 EFLAGS: 00000246 ORIG_RAX: 0000000000000001 [ 615.676626] RAX: ffffffffffffffda RBX: 00007ffc7e451f50 RCX: 0000000000440719 [ 615.683896] RDX: 0000000000000018 RSI: 0000000020000080 RDI: 0000000000000003 [ 615.691163] RBP: 0000000000000000 R08: 00007ffc7e451fa0 R09: 00007ffc7e451fa0 [ 615.698433] R10: 00007ffc7e451fa0 R11: 0000000000000246 R12: 0000000000402040 [ 615.705716] R13: 00000000004020d0 R14: 0000000000000000 R15: 0000000000000000 [ 615.713058] [ 615.713058] Showing all locks held in the system: [ 615.719391] 2 locks held by khungtaskd/868: [ 615.723779] #0: (rcu_read_lock){....}, at: [<00000000dbcbeec6>] watchdog+0x1c5/0xd60 [ 615.731863] #1: (tasklist_lock){.+.+}, at: [<000000003f35a062>] debug_show_all_locks+0xd3/0x3d0 [ 615.740914] 1 lock held by rsyslogd/4176: [ 615.745062] #0: (&f->f_pos_lock){+.+.}, at: [<00000000337d089e>] __fdget_pos+0x12b/0x190 [ 615.753487] 2 locks held by getty/4266: [ 615.757468] #0: (&tty->ldisc_sem){++++}, at: [<0000000091eb7f81>] ldsem_down_read+0x37/0x40 [ 615.766151] #1: (&ldata->atomic_read_lock){+.+.}, at: [<00000000c6c6bab6>] n_tty_read+0x2ef/0x1a40 [ 615.775445] 2 locks held by getty/4267: [ 615.779414] #0: (&tty->ldisc_sem){++++}, at: [<0000000091eb7f81>] ldsem_down_read+0x37/0x40 [ 615.788098] #1: (&ldata->atomic_read_lock){+.+.}, at: [<00000000c6c6bab6>] n_tty_read+0x2ef/0x1a40 [ 615.797384] 2 locks held by getty/4268: [ 615.801362] #0: (&tty->ldisc_sem){++++}, at: [<0000000091eb7f81>] ldsem_down_read+0x37/0x40 [ 615.810048] #1: (&ldata->atomic_read_lock){+.+.}, at: [<00000000c6c6bab6>] n_tty_read+0x2ef/0x1a40 [ 615.819356] 2 locks held by getty/4269: [ 615.823332] #0: (&tty->ldisc_sem){++++}, at: [<0000000091eb7f81>] ldsem_down_read+0x37/0x40 [ 615.832025] #1: (&ldata->atomic_read_lock){+.+.}, at: [<00000000c6c6bab6>] n_tty_read+0x2ef/0x1a40 [ 615.841312] 2 locks held by getty/4270: [ 615.845286] #0: (&tty->ldisc_sem){++++}, at: [<0000000091eb7f81>] ldsem_down_read+0x37/0x40 [ 615.853966] #1: (&ldata->atomic_read_lock){+.+.}, at: [<00000000c6c6bab6>] n_tty_read+0x2ef/0x1a40 [ 615.863271] 2 locks held by getty/4271: [ 615.867245] #0: (&tty->ldisc_sem){++++}, at: [<0000000091eb7f81>] ldsem_down_read+0x37/0x40 [ 615.875928] #1: (&ldata->atomic_read_lock){+.+.}, at: [<00000000c6c6bab6>] n_tty_read+0x2ef/0x1a40 [ 615.885226] 2 locks held by getty/4272: [ 615.889286] #0: (&tty->ldisc_sem){++++}, at: [<0000000091eb7f81>] ldsem_down_read+0x37/0x40 [ 615.898875] #1: (&ldata->atomic_read_lock){+.+.}, at: [<00000000c6c6bab6>] n_tty_read+0x2ef/0x1a40 [ 615.908181] [ 615.909803] ============================================= [ 615.909803] [ 615.916827] NMI backtrace for cpu 0 [ 615.920455] CPU: 0 PID: 868 Comm: khungtaskd Not tainted 4.16.0-rc7+ #3 [ 615.927180] Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 [ 615.936505] Call Trace: [ 615.939070] dump_stack+0x194/0x24d [ 615.942672] ? arch_local_irq_restore+0x53/0x53 [ 615.947320] ? debug_show_all_locks+0x2f3/0x3d0 [ 615.952393] ? nmi_cpu_backtrace+0x1be/0x210 [ 615.956789] ? lapic_can_unplug_cpu+0xa0/0xa0 [ 615.961257] nmi_cpu_backtrace+0x1d2/0x210 [ 615.965467] ? lapic_can_unplug_cpu+0xa0/0xa0 [ 615.969938] nmi_trigger_cpumask_backtrace+0x123/0x180 [ 615.975195] arch_trigger_cpumask_backtrace+0x14/0x20 [ 615.980358] watchdog+0x90c/0xd60 [ 615.983837] ? reset_hung_task_detector+0xa0/0xa0 [ 615.988657] ? complete+0x62/0x80 [ 615.992088] ? __schedule+0x1ec0/0x1ec0 [ 615.996034] ? do_wait_intr_irq+0x3e0/0x3e0 [ 616.000328] ? __lockdep_init_map+0xe4/0x650 [ 616.004710] ? do_raw_spin_trylock+0x190/0x190 [ 616.009259] ? lockdep_init_map+0x9/0x10 [ 616.013292] ? _raw_spin_unlock_irqrestore+0x31/0xc0 [ 616.018386] ? trace_hardirqs_on_caller+0x421/0x5c0 [ 616.023378] ? trace_hardirqs_on+0xd/0x10 [ 616.027505] ? __kthread_parkme+0x176/0x240 [ 616.031800] kthread+0x33c/0x400 [ 616.035137] ? reset_hung_task_detector+0xa0/0xa0 [ 616.039949] ? kthread_stop+0x7a0/0x7a0 [ 616.043894] ret_from_fork+0x3a/0x50 [ 616.047666] Sending NMI from CPU 0 to CPUs 1: [ 616.052201] NMI backtrace for cpu 1 skipped: idling at native_safe_halt+0x6/0x10 [ 616.053194] Kernel panic - not syncing: hung_task: blocked tasks [ 616.065921] CPU: 0 PID: 868 Comm: khungtaskd Not tainted 4.16.0-rc7+ #3 [ 616.072651] Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 [ 616.081974] Call Trace: [ 616.084535] dump_stack+0x194/0x24d [ 616.088134] ? arch_local_irq_restore+0x53/0x53 [ 616.092777] ? vsnprintf+0x1ed/0x1900 [ 616.096553] panic+0x1e4/0x41c [ 616.099715] ? refcount_error_report+0x214/0x214 [ 616.104458] ? nmi_trigger_cpumask_backtrace+0xf0/0x180 [ 616.109799] watchdog+0x91d/0xd60 [ 616.113235] ? reset_hung_task_detector+0xa0/0xa0 [ 616.118048] ? complete+0x62/0x80 [ 616.121481] ? __schedule+0x1ec0/0x1ec0 [ 616.125425] ? do_wait_intr_irq+0x3e0/0x3e0 [ 616.129718] ? __lockdep_init_map+0xe4/0x650 [ 616.134097] ? do_raw_spin_trylock+0x190/0x190 [ 616.138651] ? lockdep_init_map+0x9/0x10 [ 616.142682] ? _raw_spin_unlock_irqrestore+0x31/0xc0 [ 616.147758] ? trace_hardirqs_on_caller+0x421/0x5c0 [ 616.152745] ? trace_hardirqs_on+0xd/0x10 [ 616.156866] ? __kthread_parkme+0x176/0x240 [ 616.161162] kthread+0x33c/0x400 [ 616.164497] ? reset_hung_task_detector+0xa0/0xa0 [ 616.169317] ? kthread_stop+0x7a0/0x7a0 [ 616.173264] ret_from_fork+0x3a/0x50 [ 616.177469] Dumping ftrace buffer: [ 616.181073] (ftrace buffer empty) [ 616.184756] Kernel Offset: disabled [ 616.188358] Rebooting in 86400 seconds..