https://intel-gfx-ci.01.org/tree/drm-tip/IGT_4152/shard-hsw7/igt@kms_flip@vblank-vs-modeset-suspend.html

pstore:
<3>[  553.705051] INFO: task java:992 blocked for more than 60 seconds.
<3>[  553.705064]       Tainted: G     U           4.15.0-rc8-CI-CI_DRM_3642+ #1
<3>[  553.705068] "echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
<6>[  553.705072] java            D    0   992    938 0x00000000
<4>[  553.705078] Call Trace:
<4>[  553.705089]  ? __schedule+0x3c3/0xaf0
<4>[  553.705099]  schedule+0x37/0x90
<4>[  553.705104]  io_schedule+0xd/0x30
<4>[  553.705110]  __lock_page+0x107/0x130
<4>[  553.705116]  ? add_to_page_cache_lru+0xc0/0xc0
<4>[  553.705122]  ? ext4_inode_attach_jinode.part.20+0xb0/0xb0
<4>[  553.705127]  block_page_mkwrite+0xd5/0xf0
<4>[  553.705132]  ext4_page_mkwrite+0x172/0x4e0
<4>[  553.705142]  do_page_mkwrite+0x26/0x90
<4>[  553.705148]  do_wp_page+0x16a/0x4a0
<4>[  553.705155]  __handle_mm_fault+0x610/0xdc0
<4>[  553.705168]  handle_mm_fault+0x14f/0x2f0
<4>[  553.705174]  __do_page_fault+0x2d1/0x560
<4>[  553.705182]  ? page_fault+0x36/0x60
<4>[  553.705186]  page_fault+0x4c/0x60
<4>[  553.705190] RIP: 0033:0x7f7b7bed3f4e
<4>[  553.705192] RSP: 002b:00007f7b5d8cfdd0 EFLAGS: 00010246
<4>[  553.705204] 
<4>[  553.705204] Showing all locks held in the system:
<4>[  553.705211] 2 locks held by khungtaskd/67:
<4>[  553.705216]  #0:  (rcu_read_lock){....}, at: [<000000003ae03639>] watchdog+0x9b/0x5e0
<4>[  553.705231]  #1:  (tasklist_lock){.+.+}, at: [<00000000f1536e40>] debug_show_all_locks+0x37/0x190
<4>[  553.705246] 1 lock held by khugepaged/72:
<4>[  553.705249]  #0:  (&mm->mmap_sem){++++}, at: [<00000000781e493a>] khugepaged+0x2ef/0x2510
<4>[  553.705266] 1 lock held by NetworkManager/577:
<4>[  553.705268]  #0:  (&type->i_mutex_dir_key){++++}, at: [<000000004070ee27>] lookup_slow+0xaf/0x1b0
<4>[  553.705281] 1 lock held by in:imklog/611:
<4>[  553.705283]  #0:  (&f->f_pos_lock){+.+.}, at: [<00000000a3a3cc68>] __fdget_pos+0x3a/0x50
<4>[  553.705297] 4 locks held by rs:main Q:Reg/614:
<4>[  553.705299]  #0:  (&f->f_pos_lock){+.+.}, at: [<00000000a3a3cc68>] __fdget_pos+0x3a/0x50
<4>[  553.705311]  #1:  (sb_writers#3){.+.+}, at: [<00000000f6f656c6>] vfs_write+0x158/0x1b0
<4>[  553.705325]  #2:  (&sb->s_type->i_mutex_key#14){+.+.}, at: [<0000000087205d7b>] ext4_file_write_iter+0x64/0x3a0
<4>[  553.705341]  #3:  (jbd2_handle){++++}, at: [<00000000564e383b>] start_this_handle+0xff/0x440
<4>[  553.705356] 3 locks held by java/992:
<4>[  553.705358]  #0:  (&mm->mmap_sem){++++}, at: [<00000000d6a07adb>] __do_page_fault+0x106/0x560
<4>[  553.705370]  #1:  (sb_pagefaults){.+.+}, at: [<0000000098ae8afa>] ext4_page_mkwrite+0x46/0x4e0
<4>[  553.705381]  #2:  (&ei->i_mmap_sem){++++}, at: [<0000000074bc246a>] ext4_page_mkwrite+0x5a/0x4e0
<4>[  553.705394] 1 lock held by java/1435:
<4>[  553.705396]  #0:  (&mm->mmap_sem){++++}, at: [<000000008a74f261>] vm_mmap_pgoff+0x51/0xd0
<4>[  553.705409] 1 lock held by java/1545:
<4>[  553.705411]  #0:  (&mm->mmap_sem){++++}, at: [<000000008a74f261>] vm_mmap_pgoff+0x51/0xd0
<4>[  553.705423] 3 locks held by dmesg/1154:
<4>[  553.705425]  #0:  (sb_writers#3){.+.+}, at: [<00000000f6f656c6>] vfs_write+0x158/0x1b0
<4>[  553.705438]  #1:  (&sb->s_type->i_mutex_key#14){+.+.}, at: [<0000000087205d7b>] ext4_file_write_iter+0x64/0x3a0
<4>[  553.705452]  #2:  (jbd2_handle){++++}, at: [<00000000564e383b>] start_this_handle+0xff/0x440
<4>[  553.705470] 3 locks held by kworker/u16:15/1875:
<4>[  553.705472]  #0:  ((wq_completion)"writeback"){+.+.}, at: [<0000000071cb73d1>] process_one_work+0x191/0x640
<4>[  553.705486]  #1:  ((work_completion)(&(&wb->dwork)->work)){+.+.}, at: [<0000000071cb73d1>] process_one_work+0x191/0x640
<4>[  553.705498]  #2:  (&sbi->s_journal_flag_rwsem){.+.+}, at: [<000000005cd52949>] do_writepages+0x1b/0x70
<4>[  553.705521] 2 locks held by nm-dispatcher/2118:
<4>[  553.705523]  #0:  (&mm->mmap_sem){++++}, at: [<00000000d6a07adb>] __do_page_fault+0x106/0x560
<4>[  553.705534]  #1:  (&ei->i_mmap_sem){++++}, at: [<000000005a57c964>] ext4_filemap_fault+0x1f/0x40
<4>[  553.705547] 1 lock held by rtcwake/2138:
<4>[  553.705549]  #0:  (&type->s_umount_key#33){++++}, at: [<00000000a9db9c14>] iterate_supers+0x8d/0xf0
<4>[  553.705564] 
<4>[  553.705566] =============================================
<4>[  553.705566] 
<4>[  553.705569] NMI backtrace for cpu 0
<4>[  553.705573] CPU: 0 PID: 67 Comm: khungtaskd Tainted: G     U           4.15.0-rc8-CI-CI_DRM_3642+ #1
<4>[  553.705575] Hardware name: MSI MS-7924/Z97M-G43(MS-7924), BIOS V1.12 02/15/2016
<4>[  553.705577] Call Trace:
<4>[  553.705582]  dump_stack+0x5f/0x86
<4>[  553.705587]  nmi_cpu_backtrace+0xb4/0xc0
<4>[  553.705594]  ? lapic_can_unplug_cpu+0x90/0x90
<4>[  553.705598]  nmi_trigger_cpumask_backtrace+0xb8/0xf0
<4>[  553.705603]  watchdog+0x43e/0x5e0
<4>[  553.705611]  kthread+0xfb/0x130
<4>[  553.705614]  ? reset_hung_task_detector+0x10/0x10
<4>[  553.705617]  ? _kthread_create_on_node+0x30/0x30
<4>[  553.705623]  ret_from_fork+0x37/0x50
<6>[  553.705635] Sending NMI from CPU 0 to CPUs 1-7:
<4>[  553.705646] NMI backtrace for cpu 4 skipped: idling at intel_idle+0x6f/0x120
<4>[  553.705662] NMI backtrace for cpu 1 skipped: idling at intel_idle+0x6f/0x120
<4>[  553.705667] NMI backtrace for cpu 6 skipped: idling at intel_idle+0x6f/0x120
<4>[  553.705671] NMI backtrace for cpu 2 skipped: idling at intel_idle+0x6f/0x120
<4>[  553.705676] NMI backtrace for cpu 3 skipped: idling at intel_idle+0x6f/0x120
<4>[  553.705681] NMI backtrace for cpu 7 skipped: idling at intel_idle+0x6f/0x120
<4>[  553.705685] NMI backtrace for cpu 5 skipped: idling at intel_idle+0x6f/0x120
<0>[  553.706646] Kernel panic - not syncing: hung_task: blocked tasks
<4>[  553.706652] CPU: 0 PID: 67 Comm: khungtaskd Tainted: G     U           4.15.0-rc8-CI-CI_DRM_3642+ #1
<4>[  553.706656] Hardware name: MSI MS-7924/Z97M-G43(MS-7924), BIOS V1.12 02/15/2016
<4>[  553.706659] Call Trace:
<4>[  553.706665]  dump_stack+0x5f/0x86
<4>[  553.706671]  panic+0xcf/0x20d
<4>[  553.706682]  watchdog+0x44a/0x5e0
<4>[  553.706690]  kthread+0xfb/0x130
<4>[  553.706694]  ? reset_hung_task_detector+0x10/0x10
<4>[  553.706698]  ? _kthread_create_on_node+0x30/0x30
<4>[  553.706705]  ret_from_fork+0x37/0x50
<0>[  553.707248] Dumping ftrace buffer:
<0>[  553.707322]    (ftrace buffer empty)
<0>[  553.707326] Kernel Offset: disabled