[....] Starting enhanced syslogd: rsyslogd[?25l[?1c7[ ok 8[?25h[?0c. [ 58.096485][ T26] audit: type=1800 audit(1572455087.632:25): pid=8660 uid=0 auid=4294967295 ses=4294967295 subj==unconfined op=collect_data cause=failed(directio) comm="startpar" name="cron" dev="sda1" ino=2414 res=0 [ 58.116320][ T26] audit: type=1800 audit(1572455087.632:26): pid=8660 uid=0 auid=4294967295 ses=4294967295 subj==unconfined op=collect_data cause=failed(directio) comm="startpar" name="mcstrans" dev="sda1" ino=2457 res=0 [ 58.157388][ T26] audit: type=1800 audit(1572455087.632:27): pid=8660 uid=0 auid=4294967295 ses=4294967295 subj==unconfined op=collect_data cause=failed(directio) comm="startpar" name="restorecond" dev="sda1" ino=2436 res=0 [....] 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 '10.128.0.6' (ECDSA) to the list of known hosts. syzkaller login: [ 217.898287][ T1077] INFO: task khugepaged:1084 blocked for more than 143 seconds. [ 217.906102][ T1077] Not tainted 5.4.0-rc5-next-20191030 #0 [ 217.912351][ T1077] "echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message. [ 217.921096][ T1077] khugepaged D27840 1084 2 0x80004000 [ 217.927440][ T1077] Call Trace: [ 217.930798][ T1077] __schedule+0x94a/0x1e70 [ 217.935320][ T1077] ? __sched_text_start+0x8/0x8 [ 217.940249][ T1077] ? blk_insert_cloned_request+0x530/0x530 [ 217.946065][ T1077] ? _raw_spin_unlock_irq+0x23/0x80 [ 217.951426][ T1077] ? __lock_page+0x3d9/0xab0 [ 217.956020][ T1077] ? _raw_spin_unlock_irq+0x23/0x80 [ 217.961313][ T1077] schedule+0xdc/0x2b0 [ 217.965522][ T1077] io_schedule+0x1c/0x70 [ 217.969847][ T1077] __lock_page+0x422/0xab0 [ 217.974291][ T1077] ? wait_on_page_bit+0xa60/0xa60 [ 217.979411][ T1077] ? page_cache_next_miss+0x340/0x340 [ 217.984792][ T1077] ? ___might_sleep+0x163/0x2c0 [ 217.989788][ T1077] ? __might_sleep+0x95/0x190 [ 217.994497][ T1077] mpage_prepare_extent_to_map+0xb3f/0xf90 [ 218.000416][ T1077] ? mpage_process_page_bufs+0x780/0x780 [ 218.006083][ T1077] ? rcu_read_lock_any_held.part.0+0x50/0x50 [ 218.012256][ T1077] ? __sanitizer_cov_trace_const_cmp8+0x18/0x20 [ 218.018804][ T1077] ext4_writepages+0xb6a/0x2e70 [ 218.023845][ T1077] ? __this_cpu_preempt_check+0x2c/0x190 [ 218.029692][ T1077] ? ext4_mark_inode_dirty+0x9b0/0x9b0 [ 218.035152][ T1077] ? 0xffffffff81000000 [ 218.039370][ T1077] ? mark_lock+0xc2/0x1220 [ 218.043912][ T1077] ? prep_new_page+0x19f/0x200 [ 218.048769][ T1077] ? wbc_attach_and_unlock_inode+0x515/0x920 [ 218.054753][ T1077] ? find_held_lock+0x35/0x130 [ 218.060435][ T1077] ? wbc_attach_and_unlock_inode+0x515/0x920 [ 218.066429][ T1077] ? ext4_mark_inode_dirty+0x9b0/0x9b0 [ 218.071947][ T1077] do_writepages+0xfa/0x2a0 [ 218.076473][ T1077] ? do_writepages+0xfa/0x2a0 [ 218.081343][ T1077] ? lock_downgrade+0x920/0x920 [ 218.086205][ T1077] ? page_writeback_cpu_online+0x20/0x20 [ 218.091886][ T1077] ? __kasan_check_read+0x11/0x20 [ 218.096918][ T1077] ? do_raw_spin_unlock+0x57/0x270 [ 218.102124][ T1077] ? _raw_spin_unlock+0x28/0x40 [ 218.107054][ T1077] ? __sanitizer_cov_trace_const_cmp8+0x18/0x20 [ 218.113344][ T1077] ? wbc_attach_and_unlock_inode+0x5bf/0x920 [ 218.119387][ T1077] __filemap_fdatawrite_range+0x2bc/0x3b0 [ 218.127193][ T1077] ? delete_from_page_cache_batch+0xfe0/0xfe0 [ 218.133343][ T1077] ? lockdep_hardirqs_on+0x421/0x5e0 [ 218.138691][ T1077] filemap_flush+0x24/0x30 [ 218.143113][ T1077] collapse_file+0x36b1/0x41a0 [ 218.147891][ T1077] ? rcu_lockdep_current_cpu_online+0xe3/0x130 [ 218.154102][ T1077] ? khugepaged+0x2230/0x4360 [ 218.158843][ T1077] ? trace_event_raw_event_mm_collapse_huge_page_isolate+0x370/0x370 [ 218.166925][ T1077] ? __sanitizer_cov_trace_cmp4+0x16/0x20 [ 218.172679][ T1077] ? khugepaged_find_target_node+0x142/0x180 [ 218.178730][ T1077] khugepaged+0x2da9/0x4360 [ 218.183228][ T1077] ? __kasan_check_read+0x11/0x20 [ 218.188295][ T1077] ? __lock_acquire+0x16f2/0x4a00 [ 218.193320][ T1077] ? _raw_spin_unlock_irq+0x23/0x80 [ 218.198690][ T1077] ? finish_task_switch+0x147/0x750 [ 218.203895][ T1077] ? _raw_spin_unlock_irq+0x23/0x80 [ 218.209154][ T1077] ? lockdep_hardirqs_on+0x421/0x5e0 [ 218.214459][ T1077] ? collapse_pte_mapped_thp+0xbe0/0xbe0 [ 218.220189][ T1077] ? lock_downgrade+0x920/0x920 [ 218.225043][ T1077] ? finish_wait+0x260/0x260 [ 218.229684][ T1077] ? lockdep_hardirqs_on+0x421/0x5e0 [ 218.234974][ T1077] ? trace_hardirqs_on+0x67/0x240 [ 218.240056][ T1077] ? __sanitizer_cov_trace_const_cmp1+0x1a/0x20 [ 218.246426][ T1077] ? __kthread_parkme+0x108/0x1c0 [ 218.251482][ T1077] ? __kasan_check_read+0x11/0x20 [ 218.256509][ T1077] kthread+0x361/0x430 [ 218.260665][ T1077] ? collapse_pte_mapped_thp+0xbe0/0xbe0 [ 218.266315][ T1077] ? kthread_mod_delayed_work+0x1f0/0x1f0 [ 218.272090][ T1077] ret_from_fork+0x24/0x30 [ 218.276648][ T1077] [ 218.276648][ T1077] Showing all locks held in the system: [ 218.284425][ T1077] 4 locks held by kworker/u4:4/248: [ 218.289661][ T1077] #0: ffff8880a8349128 ((wq_completion)writeback){+.+.}, at: process_one_work+0x88b/0x1740 [ 218.299808][ T1077] #1: ffff8880a90efdc0 ((work_completion)(&(&wb->dwork)->work)){+.+.}, at: process_one_work+0x8c1/0x1740 [ 218.311137][ T1077] #2: ffff88809b0d60d8 (&type->s_umount_key#32){++++}, at: trylock_super+0x22/0x110 [ 218.320660][ T1077] #3: ffff88809b0d8990 (&sbi->s_journal_flag_rwsem){.+.+}, at: do_writepages+0xfa/0x2a0 [ 218.330529][ T1077] 1 lock held by khungtaskd/1077: [ 218.335541][ T1077] #0: ffffffff88faba40 (rcu_read_lock){....}, at: debug_show_all_locks+0x5f/0x279 [ 218.344889][ T1077] 1 lock held by khugepaged/1084: [ 218.349947][ T1077] #0: ffff88809b0d8990 (&sbi->s_journal_flag_rwsem){.+.+}, at: do_writepages+0xfa/0x2a0 [ 218.359858][ T1077] 2 locks held by rsyslogd/8698: [ 218.364832][ T1077] #0: ffff8880a0a3ab20 (&f->f_pos_lock){+.+.}, at: __fdget_pos+0xee/0x110 [ 218.373481][ T1077] #1: ffff8880a0ba0a38 (&p->pi_lock){-.-.}, at: clockevents_program_event+0x15a/0x370 [ 218.383170][ T1077] 2 locks held by getty/8788: [ 218.387830][ T1077] #0: ffff888095630090 (&tty->ldisc_sem){++++}, at: ldsem_down_read+0x33/0x40 [ 218.396889][ T1077] #1: ffffc90005f3f2e0 (&ldata->atomic_read_lock){+.+.}, at: n_tty_read+0x220/0x1bf0 [ 218.406524][ T1077] 2 locks held by getty/8789: [ 218.411229][ T1077] #0: ffff888091217090 (&tty->ldisc_sem){++++}, at: ldsem_down_read+0x33/0x40 [ 218.420759][ T1077] #1: ffffc90005f292e0 (&ldata->atomic_read_lock){+.+.}, at: n_tty_read+0x220/0x1bf0 [ 218.430828][ T1077] 2 locks held by getty/8790: [ 218.435498][ T1077] #0: ffff8880a110e090 (&tty->ldisc_sem){++++}, at: ldsem_down_read+0x33/0x40 [ 218.444493][ T1077] #1: ffffc90005f4b2e0 (&ldata->atomic_read_lock){+.+.}, at: n_tty_read+0x220/0x1bf0 [ 218.454104][ T1077] 2 locks held by getty/8791: [ 218.458960][ T1077] #0: ffff8880a8a08090 (&tty->ldisc_sem){++++}, at: ldsem_down_read+0x33/0x40 [ 218.467913][ T1077] #1: ffffc90005f4f2e0 (&ldata->atomic_read_lock){+.+.}, at: n_tty_read+0x220/0x1bf0 [ 218.477521][ T1077] 2 locks held by getty/8792: [ 218.482249][ T1077] #0: ffff88809f6a8090 (&tty->ldisc_sem){++++}, at: ldsem_down_read+0x33/0x40 [ 218.491238][ T1077] #1: ffffc90005f532e0 (&ldata->atomic_read_lock){+.+.}, at: n_tty_read+0x220/0x1bf0 [ 218.500869][ T1077] 2 locks held by getty/8793: [ 218.505531][ T1077] #0: ffff888095f27090 (&tty->ldisc_sem){++++}, at: ldsem_down_read+0x33/0x40 [ 218.514523][ T1077] #1: ffffc90005f432e0 (&ldata->atomic_read_lock){+.+.}, at: n_tty_read+0x220/0x1bf0 [ 218.524172][ T1077] 2 locks held by getty/8794: [ 218.528903][ T1077] #0: ffff888091a23090 (&tty->ldisc_sem){++++}, at: ldsem_down_read+0x33/0x40 [ 218.537857][ T1077] #1: ffffc90005f212e0 (&ldata->atomic_read_lock){+.+.}, at: n_tty_read+0x220/0x1bf0 [ 218.547468][ T1077] 1 lock held by syz-execprog/8814: [ 218.553041][ T1077] #0: ffff8880a33483e8 (&ei->i_mmap_sem){++++}, at: ext4_filemap_fault+0x7e/0xb2 [ 218.562313][ T1077] [ 218.564644][ T1077] ============================================= [ 218.564644][ T1077] [ 218.573091][ T1077] NMI backtrace for cpu 0 [ 218.577442][ T1077] CPU: 0 PID: 1077 Comm: khungtaskd Not tainted 5.4.0-rc5-next-20191030 #0 [ 218.586003][ T1077] Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 [ 218.596055][ T1077] Call Trace: [ 218.599458][ T1077] dump_stack+0x172/0x1f0 [ 218.603786][ T1077] nmi_cpu_backtrace.cold+0x70/0xb2 [ 218.608978][ T1077] ? vprintk_func+0x86/0x189 [ 218.613555][ T1077] ? lapic_can_unplug_cpu.cold+0x3a/0x3a [ 218.619177][ T1077] nmi_trigger_cpumask_backtrace+0x23b/0x28b [ 218.625167][ T1077] arch_trigger_cpumask_backtrace+0x14/0x20 [ 218.631054][ T1077] watchdog+0xc8f/0x1350 [ 218.635299][ T1077] kthread+0x361/0x430 [ 218.639366][ T1077] ? reset_hung_task_detector+0x30/0x30 [ 218.644920][ T1077] ? kthread_mod_delayed_work+0x1f0/0x1f0 [ 218.650642][ T1077] ret_from_fork+0x24/0x30 [ 218.655171][ T1077] Sending NMI from CPU 0 to CPUs 1: [ 218.660730][ C1] NMI backtrace for cpu 1 skipped: idling at native_safe_halt+0xe/0x10 [ 218.661678][ T1077] Kernel panic - not syncing: hung_task: blocked tasks [ 218.675828][ T1077] CPU: 0 PID: 1077 Comm: khungtaskd Not tainted 5.4.0-rc5-next-20191030 #0 [ 218.684430][ T1077] Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 [ 218.694470][ T1077] Call Trace: [ 218.697759][ T1077] dump_stack+0x172/0x1f0 [ 218.702092][ T1077] panic+0x2e3/0x75c [ 218.707363][ T1077] ? add_taint.cold+0x16/0x16 [ 218.712035][ T1077] ? __sanitizer_cov_trace_cmp4+0x16/0x20 [ 218.717764][ T1077] ? printk_safe_flush+0xf2/0x140 [ 218.722785][ T1077] ? __sanitizer_cov_trace_const_cmp4+0x16/0x20 [ 218.729024][ T1077] ? nmi_trigger_cpumask_backtrace+0x224/0x28b [ 218.735201][ T1077] ? nmi_trigger_cpumask_backtrace+0x21b/0x28b [ 218.741351][ T1077] watchdog+0xca0/0x1350 [ 218.745598][ T1077] kthread+0x361/0x430 [ 218.749688][ T1077] ? reset_hung_task_detector+0x30/0x30 [ 218.755238][ T1077] ? kthread_mod_delayed_work+0x1f0/0x1f0 [ 218.760970][ T1077] ret_from_fork+0x24/0x30 [ 218.767153][ T1077] Kernel Offset: disabled [ 218.771486][ T1077] Rebooting in 86400 seconds..