Panic testing ZFS raidz expansion feature.

I'm using vm-bhyve-1.5.0_1. The vm-byve package is configured correctly.

# vm iso
https://download.freebsd.org/snapshots/amd64/amd64/ISO-IMAGES/15.0/FreeBSD-15.0-CURRENT-amd64-20250109-4c89d59e0cda-274641-bootonly.iso
# vm create fbsd15-13
# cd /mnt/pool2tb/vm/fbsd15-13
In fbsd15-13.conf:
memory=2G
# vm install fbsd15-13
FreeBSD-15.0-CURRENT-amd64-20250109-4c89d59e0cda-274641-bootonly.iso
# vm console fbsd15-13
Install the OS and switch off the VM.
# truncate -s 10G disk1.img
# truncate -s 10G disk2.img
# truncate -s 10G disk3.img
# truncate -s 10G disk4.img
lines added in fbsd15-13.conf:
disk1_type="virtio-blk"
disk1_name="disk1.img"
disk2_type="virtio-blk"
disk2_name="disk2.img"
disk3_type="virtio-blk"
disk3_name="disk3.img"
disk4_type="virtio-blk"
disk4_name="disk4.img"
# vm start fbsd15-13
# vm console fbsd15-13
In the VM:
# zpool create tank raidz1 vtbd1 vtbd2 vtbd3
# zpool attach tank raidz1-0 vtbd4
panic: VERIFY(vd == vd->vdev_top) failed

cpuid = 0
time = 1736497428
KDB: stack backtrace:
db_trace_self_wrapper() at db_trace_self_wrapper+0x2b/frame
0xfffffe005469f820
vpanic() at vpanic+0x136/frame 0xfffffe005469f950
spl_panic() at spl_panic+0x3a/frame 0xfffffe005469f9b0
zio_vdev_io_start() at zio_vdev_io_start+0x63a/frame 0xfffffe005469fa00
zio_nowait() at zio_nowait+0x10c/frame 0xfffffe005469fa40
vdev_check_boot_reserve() at vdev_check_boot_reserve+0x7a/frame
0xfffffe005469fa70
spa_vdev_attach() at spa_vdev_attach+0x712/frame 0xfffffe005469faf0
zfs_ioc_vdev_attach() at zfs_ioc_vdev_attach+0x75/frame 0xfffffe005469fb30
zfsdev_ioctl_common() at zfsdev_ioctl_common+0x49a/frame 0xfffffe005469fbd0
zfsdev_ioctl() at zfsdev_ioctl+0xfb/frame 0xfffffe005469fc00
devfs_ioctl() at devfs_ioctl+0xd1/frame 0xfffffe005469fc50
vn_ioctl() at vn_ioctl+0xb6/frame 0xfffffe005469fcc0
devfs_ioctl_f() at devfs_ioctl_f+0x1e/frame 0xfffffe005469fce0
kern_ioctl() at kern_ioctl+0x286/frame 0xfffffe005469fd40
sys_ioctl() at sys_ioctl+0x12f/frame 0xfffffe005469fe00
amd64_syscall() at amd64_syscall+0x158/frame 0xfffffe005469ff30
fast_syscall_common() at fast_syscall_common+0xf8/frame 0xfffffe005469ff30
--- syscall (54, FreeBSD ELF64, ioctl), rip = 0x2f2054f58cca, rsp =
0x2f2048e41cf8, rbp = 0x2f2048e41d60 ---
KDB: enter: panic
[ thread pid 999 tid 100184 ]
Stopped at      kdb_enter+0x33: movq    $0,0x10538d2(%rip)
db>
--
Regards,
Maurizio