geom bsd strangeness in extended partition

GEOM issues warnings during scanning bsdlabels in extended partition:

WARNING: Expected rawoffset 9269505, found 9269568
GEOM: Configure ad0s5b, start 8192 length 524288000 end 524296191
GEOM: Configure ad0s5c, start 0 length 8134769664 end 8134769663
GEOM: Configure ad0s5e, start 524296192 length 7603321344 end 8127617535
WARNING: Expected rawoffset 9269505, found 30025548
GEOM: Configure ad0s11b, start 8192 length 524279808 end 524287999
GEOM: Configure ad0s11c, start 0 length 16376500224 end 16376500223
GEOM: Configure ad0s11e, start 524288000 length 15852212224 end 16376500223
WARNING: Expected rawoffset 9269505, found 62010963
GEOM: Configure ad0s12c, start 0 length 1011677184 end 1011677183
WARNING: Expected rawoffset 9269505, found 160633935
GEOM: Configure ad0s13c, start 0 length 37811612160 end 37811612159
GEOM: Configure ad0s13e, start 0 length 37811612160 end 37811612159

Slices 5, 12 and 13 are marked 0xa5 (FreeBSD).
This is quite strange why 9269505 is expected in all cases.
9269505 is absolute start of extended partition on this drive:

(earlier in dmesg.boot)
GEOM: new disk ad0
[0] f:80 typ:6 s(CHS):0/1/1 e(CHS):186/254/63 s:63 l:3004092
[1] f:00 typ:15 s(CHS):577/0/1 e(CHS):1023/254/63 s:9269505 l:225215235
[2] f:00 typ:165 s(CHS):187/0/1 e(CHS):257/254/63 s:3004155 l:1140615
[3] f:00 typ:165 s(CHS):258/0/1 e(CHS):576/254/63 s:4144770 l:5124735

There is no problem in interaction of main partitions of 4.9 (resides in
/dev/ad0s3) and 5.2 (resides in /dev/ad0s4). But, attempt to see virgin
4.9 label in ad0s12 (created with `disklabel -r -w ad0s12 auto') fails in 5.2.
OTOH, virgin 5.2 disklabel is read by 5.2 without problems,
but 4.9 swears:

[...skip common data...]
8 partitions:
#        size   offset    fstype   [fsize bsize bps/cpg]
  a:  1975916  9269521    unused        0     0         # (Cyl. 9195*- 11156*)
  c:  1975932  9269505    unused        0     0         # (Cyl. 9195*- 11156*)
super block size 0
partition a: offset past end of unit
partition a: partition extends past end of unit
partition c: offset past end of unit
partition c: partition extends past end of unit
Warning, partition c doesn't start at 0!
Warning, An incorrect partition c may cause problems for standard system utiliti
es

Simple disklabel content dump shows that offset 9269505 is really written
in raw disklabel. E.g. hexdump:

00000090  00 00 00 00 6c 26 1e 00  11 71 8d 00 00 08 00 00  |....l&...q......|
000000a0  07 08 88 6f 00 00 00 00  00 00 00 00 00 00 00 00  |...o............|
000000b0  00 00 00 00 7c 26 1e 00  01 71 8d 00 00 00 00 00  |....|&...q......|
000000c0  00 00 00 00 00 00 00 00  00 00 00 00 00 00 00 00  |................|
*
00000200

(I underlined p_offset for `a' and `c')

kern.geom.conftxt from 5.2:

0 DISK ad2 41174138880 512 hd 16 sc 63
1 MBR ad2s3 33156103680 512 i 2 o 8011422720 ty 15
2 MBREXT ad2s12 9162929664 512 i 7 o 23993174016 ty 12
2 MBREXT ad2s11 5272372224 512 i 6 o 18720769536 ty 12
2 MBREXT ad2s10 1044578304 512 i 5 o 17676158976 ty 131
2 MBREXT ad2s9 534610944 512 i 4 o 17141515776 ty 130
2 MBREXT ad2s8 8389753344 512 i 3 o 8751730176 ty 12
2 MBREXT ad2s7 8389753344 512 i 2 o 361944576 ty 3
2 MBREXT ad2s6 32868864 512 i 1 o 329043456 ty 131
2 MBREXT ad2s5 328978944 512 i 0 o 32256 ty 131
1 MBR ad2s1 2105639424 512 i 0 o 32256 ty 2
0 DISK ad0 120060444672 512 hd 16 sc 63
1 MBR ad0s4 2623864320 512 i 3 o 2122122240 ty 165
2 BSD ad0s4e 2097152000 512 i 4 o 524288000 ty 7
2 BSD ad0s4c 2623864320 512 i 2 o 0 ty 0
2 BSD ad0s4a 524288000 512 i 0 o 0 ty 7
1 MBR ad0s3 583994880 512 i 2 o 1538127360 ty 165
2 BSD ad0s3c 583994880 512 i 2 o 0 ty 0
2 BSD ad0s3a 583994880 512 i 0 o 0 ty 7
1 MBR ad0s2 115310200320 512 i 1 o 4745986560 ty 15
2 MBREXT ad0s13 37811612160 512 i 8 o 77498588160 ty 165
3 BSD ad0s13e 37811612160 512 i 4 o 0 ty 7
3 BSD ad0s13c 37811612160 512 i 2 o 0 ty 0
2 MBREXT ad0s12 1011677184 512 i 7 o 27003626496 ty 165
3 BSD ad0s12c 1011677184 512 i 2 o 0 ty 0
2 MBREXT ad0s11 16376500224 512 i 6 o 10627094016 ty 165
3 BSD ad0s11e 15852212224 512 i 4 o 524288000 ty 7
3 BSD ad0s11c 16376500224 512 i 2 o 0 ty 0
3 BSD ad0s11b 524279808 512 i 1 o 8192 ty 1
2 MBREXT ad0s10 328978944 512 i 5 o 10298082816 ty 131
2 MBREXT ad0s9 847171584 512 i 4 o 9450878976 ty 3
2 MBREXT ad0s8 8193024 512 i 3 o 9442653696 ty 3
2 MBREXT ad0s7 263176704 512 i 2 o 9179444736 ty 130
2 MBREXT ad0s6 1044578304 512 i 1 o 8134834176 ty 131
2 MBREXT ad0s5 8134769664 512 i 0 o 32256 ty 165
3 BSD ad0s5e 7603321344 512 i 4 o 524296192 ty 7
3 BSD ad0s5c 8134769664 512 i 2 o 0 ty 0
3 BSD ad0s5b 524288000 512 i 1 o 8192 ty 1
1 MBR ad0s1 1538095104 512 i 0 o 32256 ty 6

System: 5.2-BETA-20031124; but I didn't seen later commits which can
fix it.

Please ask if additional info is needed to fix.


-netch-