Subject: savecore failure
To: None <tech-kern@netbsd.org, port-amd64@netbsd.org>
From: Edgar =?iso-8859-1?B?RnXf?= <ef@math.uni-bonn.de>
List: tech-kern
Date: 06/14/2007 15:29:45
I don't really know where to put this. Technically savecore/libkvm is userland. Dumping is kernel, but the problem might well be amd64-specific.
I dumped a 4.0beta2/amd64 (typing sync in DDB) and upon reboot, savecore said "no core dump".
I gdb'd savecore -n -v and the test that fails is the check for dumpmagic in dump_exists.
I ktrace'd savecore and the relevant part reads as follows:
3626 1 savecore CALL lseek(8,0,0x104071000,0)
(this is the lseek in lib/libkvm/kvm.c:911)
3626 1 savecore RET lseek 4362539008/0x104071000
3626 1 savecore CALL close(3)
3626 1 savecore RET close 0
3626 1 savecore CALL close(4)
3626 1 savecore RET close 0
3626 1 savecore CALL close(6)
3626 1 savecore RET close 0
3626 1 savecore CALL close(5)
3626 1 savecore RET close 0
(now we are in sbin/savecore/savecore.c dump_exists())
3626 1 savecore CALL pread(8,0x7f7fffffeb78,8,0,0x10477cff8)
3626 1 savecore GIO fd 8 read 8 bytes
"# w\0\0\0\0\0"
3626 1 savecore RET pread 8
3626 1 savecore CALL pread(8,0x7f7fffffeb78,8,0,0x104782ff0)
3626 1 savecore GIO fd 8 read 8 bytes
"#0w\0\0\0\0\0"
3626 1 savecore RET pread 8
3626 1 savecore CALL pread(8,0x7f7fffffeb78,8,0,0x104783018)
3626 1 savecore GIO fd 8 read 8 bytes
"c\M^@w\0\0\0\0\0"
3626 1 savecore RET pread 8
3626 1 savecore CALL pread(8,0x7f7fffffeb70,8,0,0x104788058)
3626 1 savecore GIO fd 8 read 8 bytes
"c\M-1`\0\0\0\0\0"
3626 1 savecore RET pread 8
3626 1 savecore CALL pread(8,0x7f7fffffec1c,4,0,0x10461b33c)
(now this is the kread for newdumpmag; note that 0x10461b33c/0x200=0t8532185)
3626 1 savecore GIO fd 8 read 4 bytes
"\0\0\0\0"
3626 1 savecore RET pread 4
3626 1 savecore CALL pread(8,0x7f7fffffeb78,8,0,0x10477cff8)
3626 1 savecore GIO fd 8 read 8 bytes
"# w\0\0\0\0\0"
3626 1 savecore RET pread 8
3626 1 savecore CALL pread(8,0x7f7fffffeb78,8,0,0x104782ff0)
3626 1 savecore GIO fd 8 read 8 bytes
"#0w\0\0\0\0\0"
3626 1 savecore RET pread 8
3626 1 savecore CALL pread(8,0x7f7fffffeb78,8,0,0x104783018)
3626 1 savecore GIO fd 8 read 8 bytes
"c\M^@w\0\0\0\0\0"
3626 1 savecore RET pread 8
3626 1 savecore CALL pread(8,0x7f7fffffeb70,8,0,0x104788058)
3626 1 savecore GIO fd 8 read 8 bytes
"c\M-1`\0\0\0\0\0"
3626 1 savecore RET pread 8
3626 1 savecore CALL pread(8,0x504a28,4,0,0x10461b340)
(this is the kread for dumpsize)
3626 1 savecore GIO fd 8 read 4 bytes
"\0\0\0\0"
3626 1 savecore RET pread 4
(and then it fails)
Maybe I've some off-by-one-error in my head, but if I do a
dd if=/dev/sd0b skip=8532185 | hexdump -C
I get nothing correlating to what I expect to be in that block.
However, if I back up one block, I get mostly what I expect:
dd if=/dev/sd0b skip=8532184 | hexdump -C
00000000 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 |................|
*
00000020 03 36 49 80 ff ff ff ff ff ff ff ff 00 00 00 00 |.6I.ÿÿÿÿÿÿÿÿ....|
00000030 50 24 36 80 ff ff ff ff 10 24 36 80 ff ff ff ff |P$6.ÿÿÿÿ.$6.ÿÿÿÿ|
00000040 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 |................|
*
00000060 00 00 e0 fe 00 00 00 00 00 00 00 00 00 00 00 00 |..àþ............|
00000070 00 7b 02 09 00 80 ff ff 00 00 00 00 00 00 00 00 |.{....ÿÿ........|
00000080 01 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 |................|
00000090 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 |................|
000000a0 00 00 00 80 11 0e 00 10 00 00 00 80 11 0e 00 20 |............... |
000000b0 00 00 00 80 11 0e 00 40 00 00 00 80 86 80 2d 12 |.......@......-.|
000000c0 00 00 00 80 86 80 92 71 00 10 00 80 aa aa 21 11 |.......q....ªª!.|
000000d0 00 18 00 80 aa aa 12 11 00 00 00 80 39 10 41 07 |....ªª......9.A.|
000000e0 00 00 00 00 ff ff ff ff 00 00 00 00 00 00 00 00 |....ÿÿÿÿ........|
000000f0 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 |................|
00000100 00 00 00 00 01 00 00 00 00 00 00 01 00 00 00 00 |................|
00000110 00 00 00 00 01 00 00 00 00 00 00 00 00 00 00 00 |................|
00000120 80 ce 35 80 ff ff ff ff f0 cb 35 80 ff ff ff ff |.Î5.ÿÿÿÿðË5.ÿÿÿÿ|
00000130 30 d2 35 80 ff ff ff ff c0 d4 35 80 ff ff ff ff |0Ò5.ÿÿÿÿÀÔ5.ÿÿÿÿ|
00000140 50 d3 35 80 ff ff ff ff 30 c6 35 80 ff ff ff ff |PÓ5.ÿÿÿÿ0Æ5.ÿÿÿÿ|
00000150 c0 c4 35 80 ff ff ff ff d0 c9 35 80 ff ff ff ff |ÀÄ5.ÿÿÿÿÐÉ5.ÿÿÿÿ|
00000160 50 cd 35 80 ff ff ff ff d0 c7 35 80 ff ff ff ff |PÍ5.ÿÿÿÿÐÇ5.ÿÿÿÿ|
00000170 50 c6 35 80 ff ff ff ff 40 c5 35 80 ff ff ff ff |PÆ5.ÿÿÿÿ@Å5.ÿÿÿÿ|
00000180 f0 c4 35 80 ff ff ff ff 00 00 00 00 00 00 00 00 |ðÄ5.ÿÿÿÿ........|
00000190 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 |................|
*
000001c0 80 ce 35 80 ff ff ff ff f0 cb 35 80 ff ff ff ff |.Î5.ÿÿÿÿðË5.ÿÿÿÿ|
000001d0 30 d2 35 80 ff ff ff ff c0 d4 35 80 ff ff ff ff |0Ò5.ÿÿÿÿÀÔ5.ÿÿÿÿ|
000001e0 50 d3 35 80 ff ff ff ff 30 c6 35 80 ff ff ff ff |PÓ5.ÿÿÿÿ0Æ5.ÿÿÿÿ|
000001f0 c0 c4 35 80 ff ff ff ff 00 00 00 00 00 00 00 00 |ÀÄ5.ÿÿÿÿ........|
00000200 50 cd 35 80 ff ff ff ff d0 c7 35 80 ff ff ff ff |PÍ5.ÿÿÿÿÐÇ5.ÿÿÿÿ|
00000210 50 c6 35 80 ff ff ff ff 40 c5 35 80 ff ff ff ff |PÆ5.ÿÿÿÿ@Å5.ÿÿÿÿ|
00000220 f0 c4 35 80 ff ff ff ff 00 00 00 00 00 00 00 00 |ðÄ5.ÿÿÿÿ........|
00000230 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 |................|
00000240 00 00 00 01 00 00 00 00 00 00 00 00 00 00 00 00 |................|
00000250 00 00 00 01 00 00 00 00 00 5d 36 80 ff ff ff ff |.........]6.ÿÿÿÿ|
00000260 80 ce 35 80 ff ff ff ff f0 cb 35 80 ff ff ff ff |.Î5.ÿÿÿÿðË5.ÿÿÿÿ|
00000270 30 d2 35 80 ff ff ff ff c0 d4 35 80 ff ff ff ff |0Ò5.ÿÿÿÿÀÔ5.ÿÿÿÿ|
00000280 50 d3 35 80 ff ff ff ff 30 c6 35 80 ff ff ff ff |PÓ5.ÿÿÿÿ0Æ5.ÿÿÿÿ|
00000290 c0 c4 35 80 ff ff ff ff d0 c9 35 80 ff ff ff ff |ÀÄ5.ÿÿÿÿÐÉ5.ÿÿÿÿ|
000002a0 50 cd 35 80 ff ff ff ff d0 c7 35 80 ff ff ff ff |PÍ5.ÿÿÿÿÐÇ5.ÿÿÿÿ|
000002b0 50 c6 35 80 ff ff ff ff 40 c5 35 80 ff ff ff ff |PÆ5.ÿÿÿÿ@Å5.ÿÿÿÿ|
000002c0 f0 c4 35 80 ff ff ff ff 00 00 00 00 02 00 00 00 |ðÄ5.ÿÿÿÿ........|
000002d0 ff ff ff ff 00 00 00 00 00 00 00 00 00 00 00 00 |ÿÿÿÿ............|
000002e0 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 |................|
000002f0 00 00 00 00 00 00 00 00 61 6d 64 36 34 00 78 38 |........amd64.x8|
00000300 36 5f 36 34 00 00 00 00 d0 07 00 00 01 00 00 00 |6_64....Ð.......|
00000310 00 08 c7 07 00 80 ff ff 00 00 c7 07 00 80 ff ff |..Ç...ÿÿ..Ç...ÿÿ|
00000320 00 04 c7 07 00 80 ff ff e0 15 36 80 ff ff ff ff |..Ç...ÿÿà.6.ÿÿÿÿ|
00000330 b0 15 36 80 ff ff ff ff 00 00 00 00 00 00 00 00 |°.6.ÿÿÿÿ........|
00000340 00 00 00 00 00 00 00 00 87 03 82 00 00 00 00 00 |................|
This correlates perfectly to
gdb /netbsd
target kcore /dev/mem
(gdb) x/x 0xffffffff8060b000
0xffffffff8060b000 <smi_bus+32>: 0x00000000
0xffffffff8060b004 <smi_bus+36>: 0x00000000
0xffffffff8060b008 <smi_bus+40>: 0x00000000
0xffffffff8060b00c <smi_bus+44>: 0x00000000
0xffffffff8060b010 <smi_bus+48>: 0x00000000
0xffffffff8060b014 <smi_bus+52>: 0x00000000
0xffffffff8060b018 <smi_bus+56>: 0x00000000
0xffffffff8060b01c <smi_bus+60>: 0x00000000
0xffffffff8060b020 <nmi_bus>: 0x80493603
0xffffffff8060b024 <nmi_bus+4>: 0xffffffff
0xffffffff8060b028 <nmi_bus+8>: 0xffffffff
0xffffffff8060b02c <nmi_bus+12>: 0x00000000
0xffffffff8060b030 <nmi_bus+16>: 0x80362450
0xffffffff8060b034 <nmi_bus+20>: 0xffffffff
0xffffffff8060b038 <nmi_bus+24>: 0x80362410
0xffffffff8060b03c <nmi_bus+28>: 0xffffffff
0xffffffff8060b040 <nmi_bus+32>: 0x00000000
0xffffffff8060b044 <nmi_bus+36>: 0x00000000
0xffffffff8060b048 <nmi_bus+40>: 0x00000000
0xffffffff8060b04c <nmi_bus+44>: 0x00000000
0xffffffff8060b050 <nmi_bus+48>: 0x00000000
0xffffffff8060b054 <nmi_bus+52>: 0x00000000
0xffffffff8060b058 <nmi_bus+56>: 0x00000000
0xffffffff8060b05c <nmi_bus+60>: 0x00000000
0xffffffff8060b060 <mpacpi_lapic_base>: 0xfee00000
0xffffffff8060b064 <mpacpi_lapic_base+4>: 0x00000000
0xffffffff8060b068 <acpi_intrcold>: 0x00000000
0xffffffff8060b06c <acpi_intrcold+4>: 0x00000000
0xffffffff8060b070 <acpi_intr_deferq>: 0x09027b00
0xffffffff8060b074 <acpi_intr_deferq+4>: 0xffff8000
0xffffffff8060b078 <acpi_intr_deferq+8>: 0x00000000
0xffffffff8060b07c <acpi_intr_deferq+12>: 0x00000000
0xffffffff8060b080 <pci_mode>: 0x00000001
0xffffffff8060b084 <pci_conf_slock>: 0x00000000
0xffffffff8060b088 <pci_conf_slock+4>: 0x00000000
0xffffffff8060b08c <pci_conf_slock+8>: 0x00000000
0xffffffff8060b090 <pci_conf_slock+12>: 0x00000000
0xffffffff8060b094 <pci_conf_slock+16>: 0x00000000
0xffffffff8060b098 <pci_conf_slock+20>: 0x00000000
0xffffffff8060b09c <pci_conf_slock+24>: 0x00000000
0xffffffff8060b0a0 <pcim1_quirk_tbl>: 0x80000000
0xffffffff8060b0a4 <pcim1_quirk_tbl+4>: 0x10000e11
0xffffffff8060b0a8 <pcim1_quirk_tbl+8>: 0x80000000
0xffffffff8060b0ac <pcim1_quirk_tbl+12>: 0x20000e11
0xffffffff8060b0b0 <pcim1_quirk_tbl+16>: 0x80000000
0xffffffff8060b0b4 <pcim1_quirk_tbl+20>: 0x40000e11
0xffffffff8060b0b8 <pcim1_quirk_tbl+24>: 0x80000000
0xffffffff8060b0bc <pcim1_quirk_tbl+28>: 0x122d8086
0xffffffff8060b0c0 <pcim1_quirk_tbl+32>: 0x80000000
0xffffffff8060b0c4 <pcim1_quirk_tbl+36>: 0x71928086
0xffffffff8060b0c8 <pcim1_quirk_tbl+40>: 0x80001000
0xffffffff8060b0cc <pcim1_quirk_tbl+44>: 0x1121aaaa
0xffffffff8060b0d0 <pcim1_quirk_tbl+48>: 0x80001800
0xffffffff8060b0d4 <pcim1_quirk_tbl+52>: 0x1112aaaa
0xffffffff8060b0d8 <pcim1_quirk_tbl+56>: 0x80000000
0xffffffff8060b0dc <pcim1_quirk_tbl+60>: 0x07411039
0xffffffff8060b0e0 <pcim1_quirk_tbl+64>: 0x00000000
0xffffffff8060b0e4 <pcim1_quirk_tbl+68>: 0xffffffff
0xffffffff8060b0e8 <pcim1_quirk_tbl+72>: 0x00000000
0xffffffff8060b0ec <pcim1_quirk_tbl+76>: 0x00000000
0xffffffff8060b0f0 <pcim1_quirk_tbl+80>: 0x00000000
0xffffffff8060b0f4 <pcim1_quirk_tbl+84>: 0x00000000
0xffffffff8060b0f8 <pcim1_quirk_tbl+88>: 0x00000000
0xffffffff8060b0fc <pcim1_quirk_tbl+92>: 0x00000000
0xffffffff8060b100 <pci_bus_dma_tag>: 0x00000000
0xffffffff8060b104 <pci_bus_dma_tag+4>: 0x00000001
0xffffffff8060b108 <pci_bus_dma_tag+8>: 0x01000000
0xffffffff8060b10c <pci_bus_dma_tag+12>: 0x00000000
0xffffffff8060b110 <pci_bus_dma_tag+16>: 0x00000000
0xffffffff8060b114 <pci_bus_dma_tag+20>: 0x00000001
0xffffffff8060b118 <pci_bus_dma_tag+24>: 0x00000000
0xffffffff8060b11c <pci_bus_dma_tag+28>: 0x00000000
0xffffffff8060b120 <pci_bus_dma_tag+32>: 0x8035ce80
0xffffffff8060b124 <pci_bus_dma_tag+36>: 0xffffffff
0xffffffff8060b128 <pci_bus_dma_tag+40>: 0x8035cbf0
0xffffffff8060b12c <pci_bus_dma_tag+44>: 0xffffffff
0xffffffff8060b130 <pci_bus_dma_tag+48>: 0x8035d230
0xffffffff8060b134 <pci_bus_dma_tag+52>: 0xffffffff
0xffffffff8060b138 <pci_bus_dma_tag+56>: 0x8035d4c0
0xffffffff8060b13c <pci_bus_dma_tag+60>: 0xffffffff
0xffffffff8060b140 <pci_bus_dma_tag+64>: 0x8035d350
0xffffffff8060b144 <pci_bus_dma_tag+68>: 0xffffffff
0xffffffff8060b148 <pci_bus_dma_tag+72>: 0x8035c630
0xffffffff8060b14c <pci_bus_dma_tag+76>: 0xffffffff
0xffffffff8060b150 <pci_bus_dma_tag+80>: 0x8035c4c0
0xffffffff8060b154 <pci_bus_dma_tag+84>: 0xffffffff
0xffffffff8060b158 <pci_bus_dma_tag+88>: 0x8035c9d0
0xffffffff8060b15c <pci_bus_dma_tag+92>: 0xffffffff
0xffffffff8060b160 <pci_bus_dma_tag+96>: 0x8035cd50
0xffffffff8060b164 <pci_bus_dma_tag+100>: 0xffffffff
0xffffffff8060b168 <pci_bus_dma_tag+104>: 0x8035c7d0
0xffffffff8060b16c <pci_bus_dma_tag+108>: 0xffffffff
0xffffffff8060b170 <pci_bus_dma_tag+112>: 0x8035c650
0xffffffff8060b174 <pci_bus_dma_tag+116>: 0xffffffff
0xffffffff8060b178 <pci_bus_dma_tag+120>: 0x8035c540
0xffffffff8060b17c <pci_bus_dma_tag+124>: 0xffffffff
0xffffffff8060b180 <pci_bus_dma_tag+128>: 0x8035c4f0
0xffffffff8060b184 <pci_bus_dma_tag+132>: 0xffffffff
0xffffffff8060b188 <pci_bus_dma_tag+136>: 0x00000000
0xffffffff8060b18c <pci_bus_dma_tag+140>: 0x00000000
0xffffffff8060b190 <pci_bus_dma_tag+144>: 0x00000000
0xffffffff8060b194 <pci_bus_dma_tag+148>: 0x00000000
0xffffffff8060b198 <pci_bus_dma_tag+152>: 0x00000000
0xffffffff8060b19c <pci_bus_dma_tag+156>: 0x00000000
0xffffffff8060b1a0 <pci_bus_dma64_tag>: 0x00000000
0xffffffff8060b1a4 <pci_bus_dma64_tag+4>: 0x00000000
0xffffffff8060b1a8 <pci_bus_dma64_tag+8>: 0x00000000
0xffffffff8060b1ac <pci_bus_dma64_tag+12>: 0x00000000
0xffffffff8060b1b0 <pci_bus_dma64_tag+16>: 0x00000000
0xffffffff8060b1b4 <pci_bus_dma64_tag+20>: 0x00000000
0xffffffff8060b1b8 <pci_bus_dma64_tag+24>: 0x00000000
0xffffffff8060b1bc <pci_bus_dma64_tag+28>: 0x00000000
0xffffffff8060b1c0 <pci_bus_dma64_tag+32>: 0x8035ce80
0xffffffff8060b1c4 <pci_bus_dma64_tag+36>: 0xffffffff
0xffffffff8060b1c8 <pci_bus_dma64_tag+40>: 0x8035cbf0
0xffffffff8060b1cc <pci_bus_dma64_tag+44>: 0xffffffff
0xffffffff8060b1d0 <pci_bus_dma64_tag+48>: 0x8035d230
0xffffffff8060b1d4 <pci_bus_dma64_tag+52>: 0xffffffff
0xffffffff8060b1d8 <pci_bus_dma64_tag+56>: 0x8035d4c0
0xffffffff8060b1dc <pci_bus_dma64_tag+60>: 0xffffffff
0xffffffff8060b1e0 <pci_bus_dma64_tag+64>: 0x8035d350
0xffffffff8060b1e4 <pci_bus_dma64_tag+68>: 0xffffffff
0xffffffff8060b1e8 <pci_bus_dma64_tag+72>: 0x8035c630
0xffffffff8060b1ec <pci_bus_dma64_tag+76>: 0xffffffff
0xffffffff8060b1f0 <pci_bus_dma64_tag+80>: 0x8035c4c0
0xffffffff8060b1f4 <pci_bus_dma64_tag+84>: 0xffffffff
0xffffffff8060b1f8 <pci_bus_dma64_tag+88>: 0x00000000
0xffffffff8060b1fc <pci_bus_dma64_tag+92>: 0x00000000
0xffffffff8060b200 <pci_bus_dma64_tag+96>: 0x8035cd50
0xffffffff8060b204 <pci_bus_dma64_tag+100>: 0xffffffff
0xffffffff8060b208 <pci_bus_dma64_tag+104>: 0x8035c7d0
0xffffffff8060b20c <pci_bus_dma64_tag+108>: 0xffffffff
0xffffffff8060b210 <pci_bus_dma64_tag+112>: 0x8035c650
0xffffffff8060b214 <pci_bus_dma64_tag+116>: 0xffffffff
0xffffffff8060b218 <pci_bus_dma64_tag+120>: 0x8035c540
0xffffffff8060b21c <pci_bus_dma64_tag+124>: 0xffffffff
0xffffffff8060b220 <pci_bus_dma64_tag+128>: 0x8035c4f0
0xffffffff8060b224 <pci_bus_dma64_tag+132>: 0xffffffff
0xffffffff8060b228 <pci_bus_dma64_tag+136>: 0x00000000
0xffffffff8060b22c <pci_bus_dma64_tag+140>: 0x00000000
0xffffffff8060b230 <pci_bus_dma64_tag+144>: 0x00000000
0xffffffff8060b234 <pci_bus_dma64_tag+148>: 0x00000000
0xffffffff8060b238 <pci_bus_dma64_tag+152>: 0x00000000
0xffffffff8060b23c <pci_bus_dma64_tag+156>: 0x00000000
0xffffffff8060b240 <isa_bus_dma_tag>: 0x01000000
0xffffffff8060b244 <isa_bus_dma_tag+4>: 0x00000000
0xffffffff8060b248 <isa_bus_dma_tag+8>: 0x00000000
0xffffffff8060b24c <isa_bus_dma_tag+12>: 0x00000000
0xffffffff8060b250 <isa_bus_dma_tag+16>: 0x01000000
0xffffffff8060b254 <isa_bus_dma_tag+20>: 0x00000000
0xffffffff8060b258 <isa_bus_dma_tag+24>: 0x80365d00
0xffffffff8060b25c <isa_bus_dma_tag+28>: 0xffffffff
0xffffffff8060b260 <isa_bus_dma_tag+32>: 0x8035ce80
0xffffffff8060b264 <isa_bus_dma_tag+36>: 0xffffffff
0xffffffff8060b268 <isa_bus_dma_tag+40>: 0x8035cbf0
0xffffffff8060b26c <isa_bus_dma_tag+44>: 0xffffffff
0xffffffff8060b270 <isa_bus_dma_tag+48>: 0x8035d230
0xffffffff8060b274 <isa_bus_dma_tag+52>: 0xffffffff
0xffffffff8060b278 <isa_bus_dma_tag+56>: 0x8035d4c0
0xffffffff8060b27c <isa_bus_dma_tag+60>: 0xffffffff
0xffffffff8060b280 <isa_bus_dma_tag+64>: 0x8035d350
0xffffffff8060b284 <isa_bus_dma_tag+68>: 0xffffffff
0xffffffff8060b288 <isa_bus_dma_tag+72>: 0x8035c630
0xffffffff8060b28c <isa_bus_dma_tag+76>: 0xffffffff
0xffffffff8060b290 <isa_bus_dma_tag+80>: 0x8035c4c0
0xffffffff8060b294 <isa_bus_dma_tag+84>: 0xffffffff
0xffffffff8060b298 <isa_bus_dma_tag+88>: 0x8035c9d0
0xffffffff8060b29c <isa_bus_dma_tag+92>: 0xffffffff
0xffffffff8060b2a0 <isa_bus_dma_tag+96>: 0x8035cd50
0xffffffff8060b2a4 <isa_bus_dma_tag+100>: 0xffffffff
0xffffffff8060b2a8 <isa_bus_dma_tag+104>: 0x8035c7d0
0xffffffff8060b2ac <isa_bus_dma_tag+108>: 0xffffffff
0xffffffff8060b2b0 <isa_bus_dma_tag+112>: 0x8035c650
0xffffffff8060b2b4 <isa_bus_dma_tag+116>: 0xffffffff
0xffffffff8060b2b8 <isa_bus_dma_tag+120>: 0x8035c540
0xffffffff8060b2bc <isa_bus_dma_tag+124>: 0xffffffff
0xffffffff8060b2c0 <isa_bus_dma_tag+128>: 0x8035c4f0
0xffffffff8060b2c4 <isa_bus_dma_tag+132>: 0xffffffff
0xffffffff8060b2c8 <powernow_initialized.8186>: 0x00000000
0xffffffff8060b2cc <powernow_initialized.8186+4>: 0x00000002
0xffffffff8060b2d0 <ddb_cpu>: 0xffffffff
0xffffffff8060b2d4 <ddb_cpu+4>: 0x00000000
0xffffffff8060b2d8 <db_trap_symbol_value>: 0x00000000
0xffffffff8060b2dc <db_trap_symbol_value+4>: 0x00000000
0xffffffff8060b2e0 <db_syscall_symbol_value>: 0x00000000
0xffffffff8060b2e4 <db_syscall_symbol_value+4>: 0x00000000
0xffffffff8060b2e8 <db_kdintr_symbol_value>: 0x00000000
0xffffffff8060b2ec <db_kdintr_symbol_value+4>: 0x00000000
0xffffffff8060b2f0 <db_trace_symbols_found>: 0x00000000
0xffffffff8060b2f4 <db_trace_symbols_found+4>: 0x00000000
0xffffffff8060b2f8 <machine>: 0x36646d61
0xffffffff8060b2fc <machine+4>: 0x38780034
0xffffffff8060b300 <machine_arch+2>: 0x34365f36
0xffffffff8060b304 <machine_arch+6>: 0x00000000
0xffffffff8060b308 <cpureset_delay>: 0x000007d0
0xffffffff8060b30c <msgbuf_p_cnt>: 0x00000001
0xffffffff8060b310 <exec_map>: 0x07c70800
0xffffffff8060b314 <exec_map+4>: 0xffff8000
0xffffffff8060b318 <mb_map>: 0x07c70000
0xffffffff8060b31c <mb_map+4>: 0xffff8000
0xffffffff8060b320 <phys_map>: 0x07c70400
0xffffffff8060b324 <phys_map+4>: 0xffff8000
0xffffffff8060b328 <delay_func>: 0x803615e0
0xffffffff8060b32c <delay_func+4>: 0xffffffff
0xffffffff8060b330 <initclock_func>: 0x803615b0
0xffffffff8060b334 <initclock_func+4>: 0xffffffff
0xffffffff8060b338 <waittime>: 0xffffffff
0xffffffff8060b33c <dumpmag>: 0x8fca0101
0xffffffff8060b340 <dumpsize>: 0x000fbf8f
0xffffffff8060b344 <dumpsize+4>: 0x00000000
0xffffffff8060b348 <dumplo>: 0x00820387
0xffffffff8060b34c <dumplo+4>: 0x00000000
0xffffffff8060b350 <idt_lock>: 0x00000000
EXCEPT for dumpmag and dunpsize.
Any ideas what's going wrong? Probably I'm making some stupid mistake for the off-by-one block. But what's zeroing out magic and size?