System crash in biovec_slab() with kernel BUG at block/bio.c:64 while using mdadm write-behind

Issue

• System crash in biovec_slab() with kernel BUG at block/bio.c:64 while using mdadm write-behind:

[  136.339712] kernel BUG at block/bio.c:64!
[  136.339746] invalid opcode: 0000 [#1] SMP PTI
[  136.339760] CPU: 3 PID: 1919 Comm: mkfs.xfs Kdump: loaded Tainted: G           OE    --------- -  - 4.18.0-372.9.1.el8.x86_64 #1
[  136.339791] Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS rel-1.13.0-48-gd9c812dda519-prebuilt.qemu.org 04/01/2014
[  136.339818] RIP: 0010:biovec_slab+0x45/0x50
....
[  136.340095] Call Trace:
[  136.340117]  bvec_alloc+0x19/0x70
[  136.340134]  bio_alloc_bioset+0x1b1/0x220
[  136.340149]  raid1_write_request+0x7ff/0xb50 [raid1]
[  136.340167]  ? md_write_start+0x16e/0x220
[  136.340183]  ? finish_wait+0x80/0x80
[  136.340196]  ? finish_wait+0x80/0x80
[  136.340207]  raid1_make_request+0x52/0x90 [raid1]
[  136.340221]  md_handle_request+0x119/0x190
[  136.340241]  ? generic_make_request_checks+0x29d/0x530
[  136.340256]  md_make_request+0x5b/0xb0
[  136.340268]  generic_make_request+0x25b/0x350
[  136.340286]  submit_bio+0x3c/0x160
[  136.340297]  submit_bio_wait+0x54/0xb0
[  136.340310]  blkdev_issue_discard+0x7a/0xd0
[  136.340327]  blk_ioctl_discard+0xdd/0x100
[  136.340344]  blkdev_common_ioctl+0x257/0x870
[  136.340357]  blkdev_ioctl+0x182/0x250
[  136.340369]  block_ioctl+0x39/0x40
[  136.340387]  do_vfs_ioctl+0xa4/0x680
[  136.340409]  ? syscall_trace_enter+0x1fb/0x2c0
[  136.340427]  ksys_ioctl+0x60/0x90
[  136.340438]  __x64_sys_ioctl+0x16/0x20
[  136.340450]  do_syscall_64+0x5b/0x1a0
[  136.340471]  entry_SYSCALL_64_after_hwframe+0x65/0xca
....