[....] Starting enhanced syslogd: rsyslogd[?25l[?1c7[ ok 8[?25h[?0c. [ 54.578398][ T26] audit: type=1800 audit(1572249972.424:25): pid=8577 uid=0 auid=4294967295 ses=4294967295 subj==unconfined op=collect_data cause=failed(directio) comm="startpar" name="cron" dev="sda1" ino=2414 res=0 [ 54.607785][ T26] audit: type=1800 audit(1572249972.424:26): pid=8577 uid=0 auid=4294967295 ses=4294967295 subj==unconfined op=collect_data cause=failed(directio) comm="startpar" name="mcstrans" dev="sda1" ino=2457 res=0 [ 54.655835][ T26] audit: type=1800 audit(1572249972.424:27): pid=8577 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 '10.128.15.210' (ECDSA) to the list of known hosts. syzkaller login: [ 213.727889][ T1080] INFO: task khugepaged:1088 blocked for more than 143 seconds. [ 213.735651][ T1080] Not tainted 5.4.0-rc4-next-20191025 #0 [ 213.743118][ T1080] "echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message. [ 213.751834][ T1080] khugepaged D27840 1088 2 0x80004000 [ 213.758239][ T1080] Call Trace: [ 213.761542][ T1080] __schedule+0x94a/0x1e70 [ 213.765979][ T1080] ? __sched_text_start+0x8/0x8 [ 213.770862][ T1080] ? blk_insert_cloned_request+0x530/0x530 [ 213.776681][ T1080] ? _raw_spin_unlock_irq+0x23/0x80 [ 213.781930][ T1080] ? __lock_page+0x3d9/0xab0 [ 213.786518][ T1080] ? _raw_spin_unlock_irq+0x23/0x80 [ 213.791759][ T1080] schedule+0xdc/0x2b0 [ 213.795830][ T1080] io_schedule+0x1c/0x70 [ 213.800127][ T1080] __lock_page+0x422/0xab0 [ 213.804536][ T1080] ? wait_on_page_bit+0xa60/0xa60 [ 213.809605][ T1080] ? page_cache_next_miss+0x340/0x340 [ 213.814982][ T1080] ? ___might_sleep+0x163/0x2c0 [ 213.819877][ T1080] ? __might_sleep+0x95/0x190 [ 213.824573][ T1080] mpage_prepare_extent_to_map+0xb3f/0xf90 [ 213.830563][ T1080] ? mpage_process_page_bufs+0x780/0x780 [ 213.836197][ T1080] ? rcu_read_lock_any_held.part.0+0x50/0x50 [ 213.842213][ T1080] ? __sanitizer_cov_trace_const_cmp8+0x18/0x20 [ 213.848493][ T1080] ext4_writepages+0xb6a/0x2e70 [ 213.853342][ T1080] ? __this_cpu_preempt_check+0x2c/0x190 [ 213.859040][ T1080] ? ext4_mark_inode_dirty+0x9b0/0x9b0 [ 213.864501][ T1080] ? 0xffffffff81000000 [ 213.869437][ T1080] ? mark_lock+0xc2/0x1220 [ 213.873844][ T1080] ? prep_new_page+0x19f/0x200 [ 213.878653][ T1080] ? wbc_attach_and_unlock_inode+0x515/0x920 [ 213.884645][ T1080] ? find_held_lock+0x35/0x130 [ 213.889457][ T1080] ? wbc_attach_and_unlock_inode+0x515/0x920 [ 213.895444][ T1080] ? ext4_mark_inode_dirty+0x9b0/0x9b0 [ 213.900936][ T1080] do_writepages+0xfa/0x2a0 [ 213.905448][ T1080] ? do_writepages+0xfa/0x2a0 [ 213.910154][ T1080] ? lock_downgrade+0x920/0x920 [ 213.915022][ T1080] ? page_writeback_cpu_online+0x20/0x20 [ 213.920700][ T1080] ? __kasan_check_read+0x11/0x20 [ 213.925725][ T1080] ? do_raw_spin_unlock+0x57/0x270 [ 213.930890][ T1080] ? _raw_spin_unlock+0x28/0x40 [ 213.935748][ T1080] ? __sanitizer_cov_trace_const_cmp8+0x18/0x20 [ 213.942050][ T1080] ? wbc_attach_and_unlock_inode+0x5bf/0x920 [ 213.948081][ T1080] __filemap_fdatawrite_range+0x2bc/0x3b0 [ 213.953802][ T1080] ? delete_from_page_cache_batch+0xfe0/0xfe0 [ 213.959911][ T1080] ? lockdep_hardirqs_on+0x421/0x5e0 [ 213.965205][ T1080] filemap_flush+0x24/0x30 [ 213.969679][ T1080] collapse_file+0x36b1/0x41a0 [ 213.974447][ T1080] ? rcu_lockdep_current_cpu_online+0xe3/0x130 [ 213.980650][ T1080] ? khugepaged+0x21d0/0x4360 [ 213.985335][ T1080] ? trace_event_raw_event_mm_collapse_huge_page_isolate+0x370/0x370 [ 213.993451][ T1080] ? __sanitizer_cov_trace_cmp4+0x16/0x20 [ 213.999904][ T1080] ? khugepaged_find_target_node+0x142/0x180 [ 214.005876][ T1080] khugepaged+0x2da9/0x4360 [ 214.010424][ T1080] ? __kasan_check_read+0x11/0x20 [ 214.015456][ T1080] ? __lock_acquire+0x16f2/0x4a00 [ 214.020521][ T1080] ? _raw_spin_unlock_irq+0x23/0x80 [ 214.025712][ T1080] ? finish_task_switch+0x147/0x750 [ 214.030967][ T1080] ? _raw_spin_unlock_irq+0x23/0x80 [ 214.036172][ T1080] ? lockdep_hardirqs_on+0x421/0x5e0 [ 214.041519][ T1080] ? collapse_pte_mapped_thp+0xbe0/0xbe0 [ 214.047154][ T1080] ? lock_downgrade+0x920/0x920 [ 214.052044][ T1080] ? finish_wait+0x260/0x260 [ 214.056630][ T1080] ? lockdep_hardirqs_on+0x421/0x5e0 [ 214.061957][ T1080] ? trace_hardirqs_on+0x67/0x240 [ 214.067012][ T1080] ? __sanitizer_cov_trace_const_cmp1+0x1a/0x20 [ 214.073291][ T1080] ? __kthread_parkme+0x108/0x1c0 [ 214.078448][ T1080] ? __kasan_check_read+0x11/0x20 [ 214.083473][ T1080] kthread+0x361/0x430 [ 214.087536][ T1080] ? collapse_pte_mapped_thp+0xbe0/0xbe0 [ 214.093230][ T1080] ? kthread_mod_delayed_work+0x1f0/0x1f0 [ 214.098997][ T1080] ret_from_fork+0x24/0x30 [ 214.103478][ T1080] [ 214.103478][ T1080] Showing all locks held in the system: [ 214.111248][ T1080] 4 locks held by kworker/u4:1/21: [ 214.116356][ T1080] #0: ffff8880a7a68528 ((wq_completion)writeback){+.+.}, at: process_one_work+0x88b/0x1740 [ 214.126495][ T1080] #1: ffff8880a9a07dc0 ((work_completion)(&(&wb->dwork)->work)){+.+.}, at: process_one_work+0x8c1/0x1740 [ 214.138526][ T1080] #2: ffff8882159440d8 (&type->s_umount_key#32){++++}, at: trylock_super+0x22/0x110 [ 214.148026][ T1080] #3: ffff888215946990 (&sbi->s_journal_flag_rwsem){.+.+}, at: do_writepages+0xfa/0x2a0 [ 214.157879][ T1080] 1 lock held by khungtaskd/1080: [ 214.162882][ T1080] #0: ffffffff88faba80 (rcu_read_lock){....}, at: debug_show_all_locks+0x5f/0x279 [ 214.172222][ T1080] 1 lock held by khugepaged/1088: [ 214.177286][ T1080] #0: ffff888215946990 (&sbi->s_journal_flag_rwsem){.+.+}, at: do_writepages+0xfa/0x2a0 [ 214.187187][ T1080] 2 locks held by getty/8705: [ 214.191932][ T1080] #0: ffff8880a166b090 (&tty->ldisc_sem){++++}, at: ldsem_down_read+0x33/0x40 [ 214.200927][ T1080] #1: ffffc90005f352e0 (&ldata->atomic_read_lock){+.+.}, at: n_tty_read+0x220/0x1bf0 [ 214.210522][ T1080] 2 locks held by getty/8706: [ 214.215179][ T1080] #0: ffff8880a6047090 (&tty->ldisc_sem){++++}, at: ldsem_down_read+0x33/0x40 [ 214.224173][ T1080] #1: ffffc90005f392e0 (&ldata->atomic_read_lock){+.+.}, at: n_tty_read+0x220/0x1bf0 [ 214.233769][ T1080] 2 locks held by getty/8707: [ 214.238508][ T1080] #0: ffff88809e452090 (&tty->ldisc_sem){++++}, at: ldsem_down_read+0x33/0x40 [ 214.250102][ T1080] #1: ffffc90005f492e0 (&ldata->atomic_read_lock){+.+.}, at: n_tty_read+0x220/0x1bf0 [ 214.259722][ T1080] 2 locks held by getty/8708: [ 214.264444][ T1080] #0: ffff8880a616e090 (&tty->ldisc_sem){++++}, at: ldsem_down_read+0x33/0x40 [ 214.274190][ T1080] #1: ffffc90005f292e0 (&ldata->atomic_read_lock){+.+.}, at: n_tty_read+0x220/0x1bf0 [ 214.283817][ T1080] 2 locks held by getty/8709: [ 214.289202][ T1080] #0: ffff88809a6ac090 (&tty->ldisc_sem){++++}, at: ldsem_down_read+0x33/0x40 [ 214.298181][ T1080] #1: ffffc90005f452e0 (&ldata->atomic_read_lock){+.+.}, at: n_tty_read+0x220/0x1bf0 [ 214.307786][ T1080] 2 locks held by getty/8710: [ 214.312455][ T1080] #0: ffff888098f20090 (&tty->ldisc_sem){++++}, at: ldsem_down_read+0x33/0x40 [ 214.322148][ T1080] #1: ffffc90005f412e0 (&ldata->atomic_read_lock){+.+.}, at: n_tty_read+0x220/0x1bf0 [ 214.331759][ T1080] 2 locks held by getty/8711: [ 214.336440][ T1080] #0: ffff8880a71de090 (&tty->ldisc_sem){++++}, at: ldsem_down_read+0x33/0x40 [ 214.345431][ T1080] #1: ffffc90005f192e0 (&ldata->atomic_read_lock){+.+.}, at: n_tty_read+0x220/0x1bf0 [ 214.355031][ T1080] 1 lock held by syz-execprog/8734: [ 214.360985][ T1080] #0: ffff8880aa01a3a8 (&ei->i_mmap_sem){++++}, at: ext4_filemap_fault+0x7e/0xb2 [ 214.370262][ T1080] [ 214.372583][ T1080] ============================================= [ 214.372583][ T1080] [ 214.381022][ T1080] NMI backtrace for cpu 0 [ 214.385353][ T1080] CPU: 0 PID: 1080 Comm: khungtaskd Not tainted 5.4.0-rc4-next-20191025 #0 [ 214.393925][ T1080] Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 [ 214.404057][ T1080] Call Trace: [ 214.407377][ T1080] dump_stack+0x172/0x1f0 [ 214.411701][ T1080] nmi_cpu_backtrace.cold+0x70/0xb2 [ 214.416894][ T1080] ? vprintk_func+0x86/0x189 [ 214.421480][ T1080] ? lapic_can_unplug_cpu.cold+0x3a/0x3a [ 214.427100][ T1080] nmi_trigger_cpumask_backtrace+0x23b/0x28b [ 214.433068][ T1080] arch_trigger_cpumask_backtrace+0x14/0x20 [ 214.438957][ T1080] watchdog+0xc8f/0x1350 [ 214.443197][ T1080] kthread+0x361/0x430 [ 214.447261][ T1080] ? reset_hung_task_detector+0x30/0x30 [ 214.452807][ T1080] ? kthread_mod_delayed_work+0x1f0/0x1f0 [ 214.458512][ T1080] ret_from_fork+0x24/0x30 [ 214.463020][ T1080] Sending NMI from CPU 0 to CPUs 1: [ 214.468323][ C1] NMI backtrace for cpu 1 skipped: idling at native_safe_halt+0xe/0x10 [ 214.470046][ T1080] Kernel panic - not syncing: hung_task: blocked tasks [ 214.483394][ T1080] CPU: 0 PID: 1080 Comm: khungtaskd Not tainted 5.4.0-rc4-next-20191025 #0 [ 214.491962][ T1080] Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 [ 214.502148][ T1080] Call Trace: [ 214.505440][ T1080] dump_stack+0x172/0x1f0 [ 214.509814][ T1080] panic+0x2e3/0x75c [ 214.513697][ T1080] ? add_taint.cold+0x16/0x16 [ 214.518361][ T1080] ? lapic_can_unplug_cpu.cold+0x3a/0x3a [ 214.523974][ T1080] ? ___preempt_schedule+0x16/0x18 [ 214.529081][ T1080] ? nmi_trigger_cpumask_backtrace+0x21b/0x28b [ 214.535229][ T1080] ? nmi_trigger_cpumask_backtrace+0x24c/0x28b [ 214.541366][ T1080] ? nmi_trigger_cpumask_backtrace+0x256/0x28b [ 214.547500][ T1080] ? nmi_trigger_cpumask_backtrace+0x21b/0x28b [ 214.553641][ T1080] watchdog+0xca0/0x1350 [ 214.557878][ T1080] kthread+0x361/0x430 [ 214.561958][ T1080] ? reset_hung_task_detector+0x30/0x30 [ 214.567493][ T1080] ? kthread_mod_delayed_work+0x1f0/0x1f0 [ 214.573200][ T1080] ret_from_fork+0x24/0x30 [ 214.579077][ T1080] Kernel Offset: disabled [ 214.583447][ T1080] Rebooting in 86400 seconds..