[....] Starting enhanced syslogd: rsyslogd[?25l[?1c7[ ok 8[?25h[?0c. [ 69.871460][ T27] audit: type=1800 audit(1572613431.243:25): pid=8851 uid=0 auid=4294967295 ses=4294967295 subj==unconfined op=collect_data cause=failed(directio) comm="startpar" name="cron" dev="sda1" ino=2414 res=0 [ 69.902517][ T27] audit: type=1800 audit(1572613431.243:26): pid=8851 uid=0 auid=4294967295 ses=4294967295 subj==unconfined op=collect_data cause=failed(directio) comm="startpar" name="mcstrans" dev="sda1" ino=2457 res=0 [ 69.946988][ T27] audit: type=1800 audit(1572613431.243:27): pid=8851 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 '10.128.10.49' (ECDSA) to the list of known hosts. syzkaller login: [ 229.372419][ T1077] INFO: task khugepaged:1084 blocked for more than 143 seconds. [ 229.380425][ T1077] Not tainted 5.4.0-rc5-next-20191031 #0 [ 229.386849][ T1077] "echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message. [ 229.395787][ T1077] khugepaged D27368 1084 2 0x80004000 [ 229.402134][ T1077] Call Trace: [ 229.406290][ T1077] __schedule+0x94a/0x1e70 [ 229.410730][ T1077] ? __sched_text_start+0x8/0x8 [ 229.415726][ T1077] ? blk_insert_cloned_request+0x530/0x530 [ 229.421806][ T1077] ? _raw_spin_unlock_irq+0x23/0x80 [ 229.427095][ T1077] ? __lock_page+0x3d9/0xab0 [ 229.431788][ T1077] ? _raw_spin_unlock_irq+0x23/0x80 [ 229.437245][ T1077] schedule+0xdc/0x2b0 [ 229.441628][ T1077] io_schedule+0x1c/0x70 [ 229.446050][ T1077] __lock_page+0x422/0xab0 [ 229.450477][ T1077] ? wait_on_page_bit+0xa60/0xa60 [ 229.456282][ T1077] ? page_cache_next_miss+0x340/0x340 [ 229.461662][ T1077] ? ___might_sleep+0x163/0x2c0 [ 229.466567][ T1077] ? __might_sleep+0x95/0x190 [ 229.471263][ T1077] mpage_prepare_extent_to_map+0xb3f/0xf90 [ 229.477181][ T1077] ? mpage_process_page_bufs+0x780/0x780 [ 229.482988][ T1077] ? rcu_read_lock_any_held.part.0+0x50/0x50 [ 229.489080][ T1077] ? __sanitizer_cov_trace_const_cmp8+0x18/0x20 [ 229.495454][ T1077] ext4_writepages+0xb6a/0x2e70 [ 229.500324][ T1077] ? get_page_from_freelist+0x21fb/0x4330 [ 229.506099][ T1077] ? find_held_lock+0x35/0x130 [ 229.510882][ T1077] ? get_page_from_freelist+0x21fb/0x4330 [ 229.516700][ T1077] ? ext4_mark_inode_dirty+0x9b0/0x9b0 [ 229.522166][ T1077] ? 0xffffffff81000000 [ 229.526397][ T1077] ? mark_lock+0xc2/0x1220 [ 229.531597][ T1077] ? prep_new_page+0x19f/0x200 [ 229.537283][ T1077] ? wbc_attach_and_unlock_inode+0x515/0x920 [ 229.543336][ T1077] ? find_held_lock+0x35/0x130 [ 229.548115][ T1077] ? wbc_attach_and_unlock_inode+0x515/0x920 [ 229.554233][ T1077] ? ext4_mark_inode_dirty+0x9b0/0x9b0 [ 229.559704][ T1077] do_writepages+0xfa/0x2a0 [ 229.564269][ T1077] ? do_writepages+0xfa/0x2a0 [ 229.569213][ T1077] ? lock_downgrade+0x920/0x920 [ 229.574198][ T1077] ? page_writeback_cpu_online+0x20/0x20 [ 229.579853][ T1077] ? __kasan_check_read+0x11/0x20 [ 229.584969][ T1077] ? do_raw_spin_unlock+0x57/0x270 [ 229.590229][ T1077] ? _raw_spin_unlock+0x28/0x40 [ 229.595275][ T1077] ? __sanitizer_cov_trace_const_cmp8+0x18/0x20 [ 229.601549][ T1077] ? wbc_attach_and_unlock_inode+0x5bf/0x920 [ 229.607829][ T1077] __filemap_fdatawrite_range+0x2bc/0x3b0 [ 229.613785][ T1077] ? delete_from_page_cache_batch+0xfe0/0xfe0 [ 229.619859][ T1077] ? lockdep_hardirqs_on+0x421/0x5e0 [ 229.625222][ T1077] filemap_flush+0x24/0x30 [ 229.629669][ T1077] collapse_file+0x36b1/0x41a0 [ 229.634514][ T1077] ? rcu_lockdep_current_cpu_online+0xe3/0x130 [ 229.640688][ T1077] ? khugepaged+0x21c0/0x4360 [ 229.645611][ T1077] ? trace_event_raw_event_mm_collapse_huge_page_isolate+0x370/0x370 [ 229.653846][ T1077] ? __sanitizer_cov_trace_cmp4+0x16/0x20 [ 229.659845][ T1077] ? khugepaged_find_target_node+0x142/0x180 [ 229.666671][ T1077] khugepaged+0x2da9/0x4360 [ 229.671207][ T1077] ? __kasan_check_read+0x11/0x20 [ 229.676357][ T1077] ? __lock_acquire+0x16f2/0x4a00 [ 229.681640][ T1077] ? _raw_spin_unlock_irq+0x23/0x80 [ 229.686940][ T1077] ? finish_task_switch+0x147/0x750 [ 229.692394][ T1077] ? _raw_spin_unlock_irq+0x23/0x80 [ 229.697620][ T1077] ? lockdep_hardirqs_on+0x421/0x5e0 [ 229.702992][ T1077] ? collapse_pte_mapped_thp+0xbe0/0xbe0 [ 229.708641][ T1077] ? lock_downgrade+0x920/0x920 [ 229.713574][ T1077] ? finish_wait+0x260/0x260 [ 229.718162][ T1077] ? lockdep_hardirqs_on+0x421/0x5e0 [ 229.723512][ T1077] ? trace_hardirqs_on+0x67/0x240 [ 229.728570][ T1077] ? __sanitizer_cov_trace_const_cmp1+0x1a/0x20 [ 229.734877][ T1077] ? __kthread_parkme+0x108/0x1c0 [ 229.739958][ T1077] ? __kasan_check_read+0x11/0x20 [ 229.745065][ T1077] kthread+0x361/0x430 [ 229.749159][ T1077] ? collapse_pte_mapped_thp+0xbe0/0xbe0 [ 229.755014][ T1077] ? kthread_mod_delayed_work+0x1f0/0x1f0 [ 229.760918][ T1077] ret_from_fork+0x24/0x30 [ 229.765593][ T1077] [ 229.765593][ T1077] Showing all locks held in the system: [ 229.773522][ T1077] 4 locks held by kworker/u4:0/7: [ 229.778546][ T1077] #0: ffff8880a7f4a528 ((wq_completion)writeback){+.+.}, at: process_one_work+0x88b/0x1740 [ 229.788851][ T1077] #1: ffff8880a988fdc0 ((work_completion)(&(&wb->dwork)->work)){+.+.}, at: process_one_work+0x8c1/0x1740 [ 229.801664][ T1077] #2: ffff8882159740d8 (&type->s_umount_key#32){++++}, at: trylock_super+0x22/0x110 [ 229.811213][ T1077] #3: ffff888215976990 (&sbi->s_journal_flag_rwsem){.+.+}, at: do_writepages+0xfa/0x2a0 [ 229.821204][ T1077] 1 lock held by khungtaskd/1077: [ 229.826470][ T1077] #0: ffffffff88faba40 (rcu_read_lock){....}, at: debug_show_all_locks+0x5f/0x279 [ 229.835879][ T1077] 1 lock held by khugepaged/1084: [ 229.841017][ T1077] #0: ffff888215976990 (&sbi->s_journal_flag_rwsem){.+.+}, at: do_writepages+0xfa/0x2a0 [ 229.851674][ T1077] 3 locks held by rsyslogd/8889: [ 229.857781][ T1077] #0: ffff8880950a30e0 (&f->f_pos_lock){+.+.}, at: __fdget_pos+0xee/0x110 [ 229.866459][ T1077] #1: ffffffff89047e80 (fs_reclaim){+.+.}, at: cache_grow_end+0x4d/0x190 [ 229.875139][ T1077] #2: ffffffff88faba40 (rcu_read_lock){....}, at: update_curr+0x2ea/0x8d0 [ 229.884924][ T1077] 2 locks held by getty/8979: [ 229.889701][ T1077] #0: ffff8880968aa090 (&tty->ldisc_sem){++++}, at: ldsem_down_read+0x33/0x40 [ 229.899007][ T1077] #1: ffffc90005f392e0 (&ldata->atomic_read_lock){+.+.}, at: n_tty_read+0x220/0x1bf0 [ 229.908691][ T1077] 2 locks held by getty/8980: [ 229.913448][ T1077] #0: ffff8880a5231090 (&tty->ldisc_sem){++++}, at: ldsem_down_read+0x33/0x40 [ 229.923166][ T1077] #1: ffffc90005f2d2e0 (&ldata->atomic_read_lock){+.+.}, at: n_tty_read+0x220/0x1bf0 [ 229.933281][ T1077] 2 locks held by getty/8981: [ 229.937968][ T1077] #0: ffff8880872b8090 (&tty->ldisc_sem){++++}, at: ldsem_down_read+0x33/0x40 [ 229.947148][ T1077] #1: ffffc90005f292e0 (&ldata->atomic_read_lock){+.+.}, at: n_tty_read+0x220/0x1bf0 [ 229.956919][ T1077] 2 locks held by getty/8982: [ 229.961614][ T1077] #0: ffff8880a3a60090 (&tty->ldisc_sem){++++}, at: ldsem_down_read+0x33/0x40 [ 229.970672][ T1077] #1: ffffc90005f4b2e0 (&ldata->atomic_read_lock){+.+.}, at: n_tty_read+0x220/0x1bf0 [ 229.980458][ T1077] 2 locks held by getty/8983: [ 229.985213][ T1077] #0: ffff8880a94b2090 (&tty->ldisc_sem){++++}, at: ldsem_down_read+0x33/0x40 [ 229.994370][ T1077] #1: ffffc90005f472e0 (&ldata->atomic_read_lock){+.+.}, at: n_tty_read+0x220/0x1bf0 [ 230.004637][ T1077] 2 locks held by getty/8984: [ 230.009317][ T1077] #0: ffff8880a5e82090 (&tty->ldisc_sem){++++}, at: ldsem_down_read+0x33/0x40 [ 230.018346][ T1077] #1: ffffc90005f352e0 (&ldata->atomic_read_lock){+.+.}, at: n_tty_read+0x220/0x1bf0 [ 230.028279][ T1077] 2 locks held by getty/8985: [ 230.033033][ T1077] #0: ffff888096f23090 (&tty->ldisc_sem){++++}, at: ldsem_down_read+0x33/0x40 [ 230.042044][ T1077] #1: ffffc90005f192e0 (&ldata->atomic_read_lock){+.+.}, at: n_tty_read+0x220/0x1bf0 [ 230.051875][ T1077] 1 lock held by syz-execprog/9004: [ 230.057940][ T1077] #0: ffff8880904df3e8 (&ei->i_mmap_sem){++++}, at: ext4_filemap_fault+0x7e/0xb2 [ 230.067310][ T1077] [ 230.069653][ T1077] ============================================= [ 230.069653][ T1077] [ 230.078271][ T1077] NMI backtrace for cpu 0 [ 230.082657][ T1077] CPU: 0 PID: 1077 Comm: khungtaskd Not tainted 5.4.0-rc5-next-20191031 #0 [ 230.091500][ T1077] Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 [ 230.101789][ T1077] Call Trace: [ 230.105098][ T1077] dump_stack+0x172/0x1f0 [ 230.109539][ T1077] nmi_cpu_backtrace.cold+0x70/0xb2 [ 230.114975][ T1077] ? vprintk_func+0x86/0x189 [ 230.119940][ T1077] ? lapic_can_unplug_cpu.cold+0x3a/0x3a [ 230.125887][ T1077] nmi_trigger_cpumask_backtrace+0x23b/0x28b [ 230.132134][ T1077] arch_trigger_cpumask_backtrace+0x14/0x20 [ 230.138414][ T1077] watchdog+0xc8f/0x1350 [ 230.142930][ T1077] kthread+0x361/0x430 [ 230.147050][ T1077] ? reset_hung_task_detector+0x30/0x30 [ 230.153029][ T1077] ? kthread_mod_delayed_work+0x1f0/0x1f0 [ 230.158965][ T1077] ret_from_fork+0x24/0x30 [ 230.163829][ T1077] Sending NMI from CPU 0 to CPUs 1: [ 230.169386][ C1] NMI backtrace for cpu 1 skipped: idling at native_safe_halt+0xe/0x10 [ 230.170319][ T1077] Kernel panic - not syncing: hung_task: blocked tasks [ 230.184617][ T1077] CPU: 0 PID: 1077 Comm: khungtaskd Not tainted 5.4.0-rc5-next-20191031 #0 [ 230.193483][ T1077] Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 [ 230.203662][ T1077] Call Trace: [ 230.206976][ T1077] dump_stack+0x172/0x1f0 [ 230.211354][ T1077] panic+0x2e3/0x75c [ 230.215277][ T1077] ? add_taint.cold+0x16/0x16 [ 230.219985][ T1077] ? __sanitizer_cov_trace_cmp4+0x16/0x20 [ 230.225837][ T1077] ? printk_safe_flush+0xf2/0x140 [ 230.232297][ T1077] ? __sanitizer_cov_trace_const_cmp4+0x16/0x20 [ 230.239042][ T1077] ? nmi_trigger_cpumask_backtrace+0x224/0x28b [ 230.245302][ T1077] ? nmi_trigger_cpumask_backtrace+0x21b/0x28b [ 230.251670][ T1077] watchdog+0xca0/0x1350 [ 230.255921][ T1077] kthread+0x361/0x430 [ 230.260120][ T1077] ? reset_hung_task_detector+0x30/0x30 [ 230.265670][ T1077] ? kthread_mod_delayed_work+0x1f0/0x1f0 [ 230.271699][ T1077] ret_from_fork+0x24/0x30 [ 230.278322][ T1077] Kernel Offset: disabled [ 230.282766][ T1077] Rebooting in 86400 seconds..