Re: Potential CGD(4) bug

On Mon, 25 May 2026 07:19:35 -0400
Greg Troxel <[email protected]> wrote:

> Could you post a link to your test program?
>
It is a closed source binary. I can share it with a few NetBSD
developers for the purpose of debugging this issue, provided they keep
it confidential and do not redistribute the binary. Otherwise, you can
try simulating similar I/O patterns with your preferred open source
alternatives.

> What about cgd without lvm?
> 
I can try it over the next few days. At this stage I'm not sure if it
is cgd, lvm, or something else, hence I'm trying to understand if
anyone else observed similar issues.

> What about 10.1 on bare metal?
> 
I don't have any spare amd64 physical hardware for this test.

> Any reason you are using 10.1 intead of the tip of netbsd-10?
> 
The 10.1 is the official release for which prebuilt ISO image are
available. I can build from sources, but I don't have a lot of spare
time to try different combinations of NetBSD. I also reproduced the
same issue with 11.0_RC2.

> You say bhyve, and I think you mean host/dom0 is FreeBSD using bhyve and
> you have NetBSD 10.1 as a VM hosted on that.   Do you mean that, or
> something else?   What do the virtual disks look like?
> 
FreeBSD-15 host using Bhyve as hypervisor and running NetBSD VM.

Hypervisor VM config:
graphics="yes"
xhci_mouse="yes"
cpu=8
memory=8G
wired_memory="yes"
network0_type="virtio-net"
network0_switch="public"
disk0_type="nvme"
disk0_name="disk0.img"
disk0_dev="file"

NetBSD VM disk partitions:
gpt show -a ld0
      start       size  index  contents
          0          1         PMBR
          1          1         Pri GPT header
          2         32         Pri GPT table
         34       2014         Unused
       2048     262144      1  GPT part - EFI System
                                 Type: efi
                                 TypeID: c12a7328-f81f-11d2-ba4b-00a0c93ec93b
                                 GUID: 25ef855c-7cfe-4c80-b054-d9de73215c73
                                 Size: 128 M
                                 Label: boot-efi
                                 Attributes: None
     264192    4194304      2  GPT part - NetBSD FFSv1/FFSv2
                                 Type: ffs
                                 TypeID: 49f48d5a-b10e-11dc-b99b-0019d1879648
                                 GUID: 59a4d833-77ba-487d-8a29-e4bba45d5ecf
                                 Size: 2048 M
                                 Label: root
                                 Attributes: None
    4458496    4194304      3  GPT part - NetBSD swap
                                 Type: swap
                                 TypeID: 49f48d32-b10e-11dc-b99b-0019d1879648
                                 GUID: e5c7a155-2405-429a-bf9e-e97785e8475c
                                 Size: 2048 M
                                 Label: swap
                                 Attributes: None
    8652800  125562880      4  GPT part - NetBSD Cryptographic Disk
                                 Type: cgd
                                 TypeID: 2db519ec-b10f-11dc-b99b-0019d1879648
                                 GUID: 395978be-4314-4e9d-a968-88ac119b9036
                                 Size: 61310 M
                                 Label: cgd
                                 Attributes: None
  134215680       2015         Unused
  134217695         32         Sec GPT table
  134217727          1         Sec GPT header

CGD created with:
cgdconfig -g -o /etc/cgd/cgd0_params -k argon2id -V gpt adiantum
cgdconfig -V re-enter cgd0 /dev/dk3 /etc/cgd/cgd0_params
gpt create -f cgd0
gpt add -a 1m -l "cgd-lvm" -t linux-lvm cgd0
cat > /etc/cgd/cgd.conf << 'EOF'
# cgd    target      [paramsfile]
cgd0     NAME=cgd    /etc/cgd/cgd0_params
EOF

LVM created with:
dkctl cgd0 listwedges
/dev/rcgd0: 1 wedge:
dk4: cgd-lvm, 125558784 blocks at 2048, type:

lvm pvcreate /dev/rdk4
lvm vgcreate vg0 /dev/rdk4
lvm lvcreate -l 100%FREE -n data vg0
newfs -O 2ea /dev/vg0/data