Hi!
Both kernel 2.4.2 and 2.4.3 have an error in handling magneto-
optical disks (MOs) with 2048-byte blocks when they are formatted
with FAT.
Conditions
----------
- Kernel 2.4.2 or 2.4.3 (most likely ALL 2.4.x kernels)
- MO with 2048-byte blocks (e.g. 3.5" 640 MB)
(it doesn't matter if it's a LIMDOW-MO or a normal MO)
- FAT fs on that MO
If any of the conditions are not met, for example
- ext2 on the MO, or
- an MO with 512-byte blocks
(e.g. 3.5" 230 MB and 3.5" 540 MB) and FAT, or
- a kernel 2.2.x,
the problem doesn't occur.
Symptoms
--------
- Directly accessing the device (e.g. dd if=/dev/sda of=/tmp/sda.bin)
is OKAY.
- Mounting the MO is OKAY.
- Navigating through the directory tree on the MO is OKAY.
- Writing files onto the MO seems to be okay (haven't tried
to read these files under 2.2.x yet)
- But as soon as you try to READ a FILE, the program (e.g. cat)
SEGFAULTs and a kernel OOPS occurs.
This happens both with the new and with the old aic7xxx
driver (as offered in kernel 2.4.3).
- After the Oops, one cannot umount the device anymore.
'fuser -v /vmo' says:
USER PID ACCESS COMMAND
/vmo root kernel mount /vmo
- mount says:
/dev/sda on /vmo type vfat (rw,noexec,nosuid,nodev)
Oops (output from ksymoops)
---------------------------
-------BEGIN--------
ksymoops 2.4.0 on i686 2.4.3. Options used
-V (default)
-k /tmp/ksyms (specified) [immediately copied from /proc after Oops]
-l /proc/modules (default)
-o /lib/modules/2.4.3/ (default)
-m /boot/System.map (specified)
Warning (compare_maps): ksyms_base symbol scsi_logging_level_R__ver_scsi_logging_level
not found in System.map. Ignoring ksyms_base entry
Apr 19 16:05:39 pc8 kernel: Unable to handle kernel NULL pointer dereference at
virtual address 00000000
Apr 19 16:05:39 pc8 kernel: 00000000
Apr 19 16:05:39 pc8 kernel: *pde = 00000000
Apr 19 16:05:39 pc8 kernel: Oops: 0000
Apr 19 16:05:39 pc8 kernel: CPU: 0
Apr 19 16:05:39 pc8 kernel: EIP: 0010:[agp_frontend_cleanup+0/-1072693248]
Apr 19 16:05:39 pc8 kernel: EFLAGS: 00010282
Apr 19 16:05:39 pc8 kernel: eax: 00000000 ebx: e4fc2cc0 ecx: 00004000 edx:
e4fc2ce0
Apr 19 16:05:39 pc8 kernel: esi: 0804cea8 edi: 00000000 ebp: 00004000 esp:
e4cebf80
Apr 19 16:05:39 pc8 kernel: ds: 0018 es: 0018 ss: 0018
Apr 19 16:05:39 pc8 kernel: Process cat (pid: 682, stackpage=e4ceb000)
Apr 19 16:05:39 pc8 kernel: Stack: c01589fd e4fc2cc0 0804cea8 00004000 e4fc2ce0
e4fc2cc0 ffffffea c012cce6
Apr 19 16:05:39 pc8 kernel: e4fc2cc0 0804cea8 00004000 e4fc2ce0 e4cea000
00004000 0804cea8 bffff604
Apr 19 16:05:39 pc8 kernel: c0106e83 00000003 0804cea8 00004000 00004000
0804cea8 bffff604 00000003
Apr 19 16:05:39 pc8 kernel: Call Trace: [fat_cache_add+173/176] [sys_read+150/208]
[system_call+51/56]
Apr 19 16:05:39 pc8 kernel: Code: Bad EIP value.
Using defaults from ksymoops -t elf32-i386 -a i386
1 warning issued. Results may not be reliable.
-------END----------
Output of 'strace -v -f -s 16384 cat /vmo/out' ('out' is an mbox file)
----------------------------------------------------------------------
-------BEGIN--------
execve("/bin/cat", ["cat", "/vmo/out"], [/* 51 vars */]) = 0
uname({sysname="Linux", nodename="pc8", release="2.4.3", version="#8 Thu Apr 19
15:46:00 CEST 2001", machine="i686"}) = 0
brk(0) = 0x804c048
open("/etc/ld.so.preload", O_RDONLY) = -1 ENOENT (No such file or directory)
open("/etc/ld.so.cache", O_RDONLY) = 3
fstat64(3, {st_dev=makedev(3, 7), st_ino=12488, st_mode=S_IFREG|0644, st_nlink=1,
st_uid=0, st_gid=0, st_blksize=4096, st_blocks=232, st_size=117364,
st_atime=2001/04/19-15:57:37, st_mtime=2001/04/18-12:33:10,
st_ctime=2001/04/18-12:33:10}) = 0
old_mmap(NULL, 117364, PROT_READ, MAP_PRIVATE, 3, 0) = 0x40017000
close(3) = 0
open("/lib/libc.so.6", O_RDONLY) = 3
[uninteresting stuff (reading from libc) deleted]
fstat64(3, {st_dev=makedev(3, 7), st_ino=28585, st_mode=S_IFREG|0755, st_nlink=1,
st_uid=0, st_gid=0, st_blksize=4096, st_blocks=2714, st_size=1382179,
st_atime=2001/04/19-15:57:37, st_mtime=2001/01/19-07:14:03,
st_ctime=2001/04/12-22:58:14}) = 0
old_mmap(NULL, 4096, PROT_READ|PROT_WRITE, MAP_PRIVATE|MAP_ANONYMOUS, -1, 0) =
0x40034000
old_mmap(NULL, 1123876, PROT_READ|PROT_EXEC, MAP_PRIVATE, 3, 0) = 0x40035000
mprotect(0x4013e000, 38436, PROT_NONE) = 0
old_mmap(0x4013e000, 24576, PROT_READ|PROT_WRITE, MAP_PRIVATE|MAP_FIXED, 3, 0x108000)
= 0x4013e000
old_mmap(0x40144000, 13860, PROT_READ|PROT_WRITE, MAP_PRIVATE|MAP_FIXED|MAP_ANONYMOUS,
-1, 0) = 0x40144000
close(3) = 0
munmap(0x40017000, 117364) = 0
getpid() = 627
brk(0) = 0x804c048
brk(0x804c070) = 0x804c070
brk(0x804d000) = 0x804d000
open("/usr/share/locale/locale.alias", O_RDONLY) = 3
fstat64(3, {st_dev=makedev(33, 3), st_ino=4868132, st_mode=S_IFREG|0644, st_nlink=1,
st_uid=0, st_gid=0, st_blksize=4096, st_blocks=8, st_size=2576,
st_atime=2001/04/19-15:56:38, st_mtime=2001/01/19-07:15:30,
st_ctime=2001/04/12-22:58:20}) = 0
old_mmap(NULL, 4096, PROT_READ|PROT_WRITE, MAP_PRIVATE|MAP_ANONYMOUS, -1, 0) =
0x40017000
[uninteresting stuff (reading from locale.alias) deleted]
read(3, "", 4096) = 0
close(3) = 0
munmap(0x40017000, 4096) = 0
open("/usr/lib/locale/de_DE/LC_CTYPE", O_RDONLY) = 3
fstat64(3, {st_dev=makedev(33, 3), st_ino=8821444, st_mode=S_IFREG|0644, st_nlink=1,
st_uid=0, st_gid=0, st_blksize=4096, st_blocks=272, st_size=133060,
st_atime=2001/04/19-15:56:38, st_mtime=2001/01/19-07:17:07,
st_ctime=2001/04/12-22:58:15}) = 0
old_mmap(NULL, 133060, PROT_READ, MAP_PRIVATE, 3, 0) = 0x40148000
close(3) = 0
fstat64(1, {st_dev=makedev(3, 7), st_ino=111848, st_mode=S_IFCHR|0620, st_nlink=1,
st_uid=0, st_gid=5, st_blksize=4096, st_blocks=0, st_rdev=makedev(4, 2),
st_atime=2001/04/19-15:57:37, st_mtime=2001/04/19-15:57:37,
st_ctime=2001/04/19-15:53:47}) = 0
open("/vmo/out", O_RDONLY|O_LARGEFILE) = 3
fstat64(3, {st_dev=makedev(8, 0), st_ino=44, st_mode=S_IFREG|0644, st_nlink=1,
st_uid=0, st_gid=0, st_blksize=16384, st_blocks=768, st_size=391404,
st_atime=2000/12/06-18:17:54, st_mtime=2000/12/06-18:17:54,
st_ctime=2000/12/06-18:17:54}) = 0
brk(0x8052000) = 0x8052000
read(3, <unfinished ...>
+++ killed by SIGSEGV +++
-------END----------
PC components
-------------
- Thunderbird 1 GHz on Abit KT7A-RAID
- 1 UDMA HD on ide0
- 1 CD on ide0
- 2 UDMA HDs on ide2 (Highpoint RAID controller, RAID
not configured)
- Fujitsu MCE3064SS 3.5" 640 MB SCSI MO drive (LIMDOW capable)
on channel A of an Adaptec 3940 (basically 2 x 2940
on one board using a PCI-to-PCI bridge)
- SuSE Linux Professional 7.1 (with home-made kernel 2.4.3)
- all Linux partitions formatted with ext2
If someone could fix this, I'd be willing to get him or her
a chocolate bar. A LARGE chocolate bar :-)
Best regards,
Marc-Jano
P.S.: Didn't find any recent email address of the FAT code maintainer.
Where should I mail such a bug to next time?
--
http://mjk.c64.org/
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