INFO: task kworker/u4:0:6 blocked for more than 140 seconds.
      Not tainted 4.17.0+ #22
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
kworker/u4:0    D54432     6      2 0x80000000
Workqueue: writeback wb_workfn (flush-7:0)
Call Trace:
 context_switch kernel/sched/core.c:2880 [inline]
 __schedule+0x651/0x770 kernel/sched/core.c:3524
 schedule+0x1cc/0x2f0 kernel/sched/core.c:3568
 blk_queue_enter+0x30a/0x970 block/blk-core.c:953
 generic_make_request+0x13b/0x18f0 block/blk-core.c:2395
 submit_bio+0x2e8/0x740 block/blk-core.c:2568
 submit_bh_wbc+0xb3b/0xe00 fs/buffer.c:3081
 __block_write_full_page+0x12ea/0x1e10 fs/buffer.c:1763
 block_write_full_page+0x32c/0x440 fs/buffer.c:2949
 blkdev_writepage+0x76/0x90 fs/block_dev.c:566
 __writepage+0xc5/0x200 mm/page-writeback.c:2302
 write_cache_pages+0x123f/0x1870 mm/page-writeback.c:2240
 generic_writepages+0x10f/0x190 mm/page-writeback.c:2326
 blkdev_writepages+0x67/0x80 fs/block_dev.c:1951
 do_writepages+0x184/0x3c0 mm/page-writeback.c:2341
 __writeback_single_inode+0x3fb/0x14b0 fs/fs-writeback.c:1323
 writeback_sb_inodes+0x8c7/0x2810 fs/fs-writeback.c:1587
 __writeback_inodes_wb+0x1e4/0x690 fs/fs-writeback.c:1656
 wb_writeback+0x964/0x1300 fs/fs-writeback.c:1765
 wb_check_old_data_flush fs/fs-writeback.c:1867 [inline]
 wb_do_writeback fs/fs-writeback.c:1920 [inline]
 wb_workfn+0x1352/0x1fb0 fs/fs-writeback.c:1949
 process_one_work+0x12e4/0x1fa0 kernel/workqueue.c:2145
 worker_thread+0x113c/0x24f0 kernel/workqueue.c:2279
 kthread+0x4db/0x6c0 kernel/kthread.c:241
 ret_from_fork+0x35/0x40 arch/x86/entry/entry_64.S:415
NMI backtrace for cpu 0
CPU: 0 PID: 804 Comm: khungtaskd Not tainted 4.17.0+ #22
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
Call Trace:
 __dump_stack lib/dump_stack.c:77 [inline]
 dump_stack+0x185/0x1d0 lib/dump_stack.c:113
 nmi_cpu_backtrace lib/nmi_backtrace.c:103 [inline]
 nmi_trigger_cpumask_backtrace+0x262/0x4c0 lib/nmi_backtrace.c:62
 arch_trigger_cpumask_backtrace+0x2c/0x40 arch/x86/kernel/apic/hw_nmi.c:38
 trigger_all_cpu_backtrace+0x2b/0x30 include/linux/nmi.h:138
 check_hung_task kernel/hung_task.c:132 [inline]
 check_hung_uninterruptible_tasks kernel/hung_task.c:190 [inline]
 watchdog+0x10d5/0x1100 kernel/hung_task.c:249
 kthread+0x4db/0x6c0 kernel/kthread.c:241
 ret_from_fork+0x35/0x40 arch/x86/entry/entry_64.S:415
Sending NMI from CPU 0 to CPUs 1:
------------[ cut here ]------------
kernel BUG at mm/kmsan/kmsan_entry.c:81!
invalid opcode: 0000 [#1] SMP PTI
Dumping ftrace buffer:
   (ftrace buffer empty)
Modules linked in:
CPU: 1 PID: 0 Comm: swapper/1 Not tainted 4.17.0+ #22
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
RIP: 0010:kmsan_nmi_enter+0x42/0x70 mm/kmsan/kmsan_entry.c:80
RSP: 0018:fffffe0000049ea8 EFLAGS: 00010046
RAX: 0000000080000000 RBX: 0000000000000001 RCX: 00000000c0000101
RDX: 00000000ffff8802 RSI: ffffffff8a00136c RDI: ffffea0000421320
RBP: fffffe0000049ef9 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000000 R12: 0000000000000000
R13: 0000000000000000 R14: 00000001991d0000 R15: 0000000000000000
FS:  0000000000000000(0000) GS:ffff88021fd00000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: ffffffffff600400 CR3: 00000001991d0000 CR4: 00000000001406e0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
Call Trace:
 <NMI>
 </NMI>
Code: 10 00 74 27 65 8b 04 25 40 90 03 00 83 c0 01 83 f8 08 7d 27 65 89 04 25 40 90 03 00 65 c6 04 25 d5 6d 0b 00 ff c3 0f 0b 90 eb fe <0f> 0b 66 90 66 2e 0f 1f 84 00 00 00 00 00 eb fe 0f 0b 66 90 66 
RIP: kmsan_nmi_enter+0x42/0x70 mm/kmsan/kmsan_entry.c:80 RSP: fffffe0000049ea8
---[ end trace 0ad31619808f7bec ]---