Problem Description
===================
CPU stuck while running fio against local disk with DD2.3

Steps to Reproduce
===================
1. format disk partition with xfs
   mkfs.xfs /dev/nvme0n1p1 -f
2. mount the partition
   mount /dev/nvme0n1p1 /mnt/local-storage/nvme
3. run fio
   fio --name=4kRandomWrite --numjobs=1 --bs=4k --iodepth=1 --filename=/mnt/local-storage/nvme/testflag --ioengine=libaio --rw=randwrite --size=1800g --runtime=3600 --time_based

uname output
============
Linux <xxx> 4.14.0-115.10.1.el7a.ppc64le #1 SMP Wed Jun 26 09:32:17 UTC 2019 ppc64le ppc64le ppc64le GNU/Linux


Dmesg warning
=============

1454 [ 1625.147048] watchdog: BUG: soft lockup - CPU#77 stuck for 22s! [kworker/77:28:44588]
1455 [ 1625.147118] Modules linked in: <...> xfs <...>
1457 [ 1625.148014] CPU: 77 PID: 44588 Comm: kworker/77:28 Kdump: loaded Not tainted 4.14.0-115.10.1.el7a.ppc64le #1
1458 [ 1625.148125] Workqueue: xfs-conv/nvme0n1p1 xfs_end_io [xfs]
1459 [ 1625.148167] task: c000007fb38f2500 task.stack: c000007f9fb64000
1460 [ 1625.148222] NIP:  c0000000000a805c LR: c0080000232e30e8 CTR: c0000000000a721c
1461 [ 1625.148306] REGS: c000007f9fb673c0 TRAP: 0901   Not tainted  (4.14.0-115.10.1.el7a.ppc64le)
1462 [ 1625.148385] MSR:  9000000000009033 <SF,HV,EE,ME,IR,DR,RI,LE>  CR: 88822180  XER: 00000000
1463 [ 1625.148470] CFAR: c0000000000a7f64 SOFTE: 1
1464 GPR00: c000006f33d27000 c000007f9fb67640 c0000000014ce300 c000006f097609d0
1465 GPR04: c000006f097609e0 0000000000000010 0000000000000001 c000006f0968e7f0
1466 GPR08: 0000000000000000 000000000040001b 0000000000018709 c008000023373e30
1467 GPR12: c0000000000a721c c000000007a44f00
1468 [ 1625.148741] NIP [c0000000000a805c] memcpy_power7+0x15c/0x800
1469 [ 1625.148808] LR [c0080000232e30e8] xfs_iext_irec_remove+0xf8/0x190 [xfs]
1470 [ 1625.148854] Call Trace:
1471 [ 1625.148898] [c000007f9fb67690] [c0080000232e3534] xfs_iext_irec_compact+0x1f4/0x290 [xfs]
1472 [ 1625.149001] [c000007f9fb676d0] [c0080000232e3b70] xfs_iext_remove+0x2d0/0x3f0 [xfs]
1473 [ 1625.149054] [c000007f9fb67730] [c0080000232a7114] xfs_bmap_add_extent_unwritten_real+0x444/0x20f0 [xfs]
1474 [ 1625.149155] [c000007f9fb67870] [c0080000232a8ea4] xfs_bmapi_convert_unwritten+0xe4/0x270 [xfs]
1475 [ 1625.149239] [c000007f9fb67920] [c0080000232aef10] xfs_bmapi_write+0x2e0/0xc40 [xfs]
1476 [ 1625.149312] [c000007f9fb67af0] [c00800002331e214] xfs_iomap_write_unwritten+0x1d4/0x340 [xfs]
1477 [ 1625.149391] [c000007f9fb67c30] [c0080000232fb294] xfs_end_io+0x114/0x150 [xfs]
1478 [ 1625.149451] [c000007f9fb67c80] [c000000000164d0c] process_one_work+0x1bc/0x5f0
1479 [ 1625.149532] [c000007f9fb67d20] [c000000000167ccc] worker_thread+0xac/0x6b0
1480 [ 1625.149585] [c000007f9fb67dc0] [c000000000171358] kthread+0x168/0x1b0
1481 [ 1625.149653] [c000007f9fb67e30] [c00000000000b65c] ret_from_kernel_thread+0x5c/0x80