bin/54900: gpt(8) can not show MBR partitions on non 512 byte/sector disks

[martin%NetBSD.org@localhost]

>Number:         54900
>Category:       bin
>Synopsis:       gpt(8) can not show MBR partitions on non 512 byte/sector disks
>Confidential:   no
>Severity:       non-critical
>Priority:       low
>Responsible:    bin-bug-people
>State:          open
>Class:          sw-bug
>Submitter-Id:   net
>Arrival-Date:   Mon Jan 27 10:05:00 +0000 2020
>Originator:     Martin Husemann
>Release:        NetBSD 9.99.42
>Organization:
The NetBSD Foundation, Inc.
>Environment:
System: NetBSD seven-days-to-the-wolves.aprisoft.de 9.99.42 NetBSD 9.99.42 (GENERIC) #345: Mon Jan 27 10:48:14 CET 2020 martin%seven-days-to-the-wolves.aprisoft.de@localhost:/work/src/sys/arch/amd64/compile/GENERIC amd64
Architecture: x86_64
Machine: amd64
>Description:

The gpt(8) utility can show MBR partitions on "normal" 512 byte/sector
disks. This does not work for disks with bigger sectors:

# fdisk sd3
Disk: /dev/rsd3
NetBSD disklabel disk geometry:
cylinders: 512, heads: 64, sectors/track: 32 (2048 sectors/cylinder)
total sectors: 1048576, bytes/sector: 2048

BIOS disk geometry:
cylinders: 66, heads: 255, sectors/track: 63 (16065 sectors/cylinder)
total sectors: 1048576

Partitions aligned to 16065 sector boundaries, offset 63

Partition table:
0: Primary DOS with 32 bit FAT - LBA (sysid 12)
    start 64, size 262144 (512 MB, Cyls 0/1/2-16/82/2)
1: <UNUSED>
2: <UNUSED>
3: <UNUSED>
No active partition.
Drive serial number: 2573559659 (0x9965676b)
# gpt show  sd3
gpt: /dev/rsd3: map entry doesn't fit media: new start + new size < start + size
(a + 36 < a + 1ff6)


>How-To-Repeat:
Format a 2k block disk (easily testable with vnd(4)) with fdisk and try to
show the partitioning with gpt.

>Fix:
n/a