[1.] One line summary of the problem:
Reading at the end of block device fails.
[2.] Full description of the problem/report:
I have three machines, all with one hard disk, and one machine always
fails reading few last kB's at the end of its hard disk. It works fine
on two other hard disks. (Disk sizes and partition information at the
end of message.)
AFAIR I've seen something like this on some CD-ROM's also (IDE CD-ROM
drive using SCSI emulation)...
Here's an example:
---
22:51:59 toosa root [/tmp]grep hda9 /proc/partitions
3 9 88326 hda9
22:52:06 toosa root [/tmp]dd if=/dev/hda9 of=/dev/null skip=88324 bs=1k
count=2
dd: /dev/hda9: Input/output error
0+0 records in
0+0 records out
---
When I run this, I get these messages on syslog:
---
Dec 7 22:52:10 toosa kernel: attempt to access beyond end of device
Dec 7 22:52:10 toosa kernel: 03:09: rw=0, want=88328, limit=88326
---
Instead, reading a few sectors from earlier position works fine:
---
22:58:41 toosa root [/tmp]dd if=/dev/hda9 of=/dev/null skip=88322 bs=1k
count=2
2+0 records in
2+0 records out
---
I wouldn't have noticed this unless the swap partition
hadn't been at the end of the hard disk... ;-) Lots of oopses at the
same time, programs crash, etc.
[3.] Keywords (i.e., modules, networking, kernel):
I/O, end of disk, block device
[4.] Kernel version (from /proc/version):
Linux version 2.4.16 (root@masiina) (gcc version 2.95.2 20000220 (Debian
GNU/Linux)) #1 Mon Nov 26 20:20:53 EET 2001
[6.] A small shell script or example program which triggers the
problem (if possible)
This script prints out command line which may trigger the problem. It
assumes (block) device to be tested is /dev/hda.
---
#!/bin/bash
HD=hda
LINE=$(grep $HD /proc/partitions | tail -1)
DEV=$(echo $LINE | awk '{print $4;}')
POS=$(echo $LINE | awk '{print $3-2;}')
echo dd if=/dev/"$DEV" of=/dev/null skip=$POS bs=1k count=2
---
[7.] Environment
[7.1.] Software (add the output of the ver_linux script here)
If some fields are empty or look unusual you may have an old version.
Compare to the current minimal requirements in Documentation/Changes.
Linux toosa 2.4.16 #1 Mon Nov 26 20:20:53 EET 2001 i586 unknown
Gnu C 2.95.2
Gnu make 3.79.1
binutils 2.9.5.0.37
...
mount 2.10q
modutils 2.4.2
e2fsprogs 1.19
reiserfsprogs 3.x.0j
PPP 2.4.0
Linux C Library 2.1.3
ldd: version 1.9.11
Procps 2.0.6
Net-tools 1.54
Console-tools 0.2.3
Sh-utils 2.0
Modules Loaded ipt_MASQUERADE iptable_nat ip_conntrack
iptable_filter rtc nls_iso8859-1 nls_cp437 msdos autofs4 ip_tables lp
parport_pc parport 3c509 minix vfat fat
util-linux is of version 2.10q. Debian doesn't seem to have fdformat any
more.
[7.2.] Processor information (from /proc/cpuinfo):
processor : 0
vendor_id : CyrixInstead
cpu family : 5
model : 2
model name : 6x86 2x Core/Bus Clock
stepping : 7
fdiv_bug : no
hlt_bug : no
f00f_bug : no
coma_bug : yes
fpu : yes
fpu_exception : yes
cpuid level : 1
wp : yes
flags : fpu cyrix_arr
bogomips : 132.30
[7.3.] Module information (from /proc/modules):
ipt_MASQUERADE 1200 1 (autoclean)
iptable_nat 12656 0 (autoclean) [ipt_MASQUERADE]
ip_conntrack 12800 1 (autoclean) [ipt_MASQUERADE iptable_nat]
iptable_filter 1696 0 (autoclean) (unused)
rtc 5472 0 (autoclean)
nls_iso8859-1 2848 2 (autoclean)
nls_cp437 4352 2 (autoclean)
msdos 4784 2 (autoclean)
autofs4 8032 0 (unused)
ip_tables 10400 5 [ipt_MASQUERADE iptable_nat iptable_filter]
lp 5824 0
parport_pc 12320 1
parport 13792 1 [lp parport_pc]
3c509 5744 1
minix 17984 0 (unused)
vfat 9264 0 (unused)
fat 29184 0 [msdos vfat]
[7.5.] Other information that might be relevant to the problem
(please look in /proc and include all information that you
think to be relevant):
Disks on all machines (first hard disk is the one I've problems with):
1: hda: 10003456 sectors (5122 MB) w/256KiB Cache, CHS=622/255/63
2: hde: 80063424 sectors (40992 MB) w/2048KiB Cache, CHS=79428/16/63,
UDMA(66)
3: hde: 60036480 sectors (30739 MB) w/1916KiB Cache, CHS=59560/16/63,
UDMA(100)
/proc/partitions (on problematic machine):
---
major minor #blocks name
3 0 5001728 hda
3 1 8001 hda1
3 2 409657 hda2
3 3 1 hda3
3 5 1028128 hda5
3 6 1919736 hda6
3 7 1534176 hda7
3 8 8001 hda8
3 9 88326 hda9
---
And on other machines:
---
major minor #blocks name
33 0 40031712 hde
33 1 15592 hde1
33 2 512064 hde2
33 3 39504024 hde3
---
and
---
major minor #blocks name
33 0 30018240 hde
33 1 8001 hde1
33 2 1028160 hde2
33 3 1 hde3
33 5 313236 hde5
33 6 722893 hde6
33 7 8001 hde7
33 8 2056288 hde8
33 9 2056288 hde9
33 10 2032191 hde10
33 11 465853 hde11
33 12 21326256 hde12
---
Partition table print from fdisk on first machine, end of hda is also
end of /dev/hda9:
---
01:14:14 toosa root [/tmp]fdisk /dev/hda
Command (m for help): p
Disk /dev/hda: 255 heads, 63 sectors, 622 cylinders
Units = cylinders of 16065 * 512 bytes
Device Boot Start End Blocks Id System
/dev/hda1 * 1 1 8001 a OS/2 Boot Manager
/dev/hda2 2 52 409657+ 6 FAT16
/dev/hda3 53 622 4578525 5 Extended
/dev/hda5 * 53 180 1028128+ 6 FAT16
/dev/hda6 * 181 419 1919736 83 Linux
/dev/hda7 * 420 610 1534176 83 Linux
/dev/hda8 * 611 611 8001 83 Linux
/dev/hda9 * 612 622 88326 82 Linux swap
---
I can't help noticing that the size of that swap partition isn't
divisible by 4 (but 2 instead). Other partitions on these disks have odd
size or are divisible by 4, I tried this on few of them with no problems.
--
Sakari Ailus
sakari.ailus@retiisi.dyndns.org
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