MO-Drive under 2.4.7 usinf vfat

Hi all,

I have just tested the new 2.4.7 kernel to see, whether it now works with a MO-Drive using the vfat filesystem. Unfortunately it still doesn't. Mounting a disk and writing to it is ok. However, when I try to read a file off the disk, the program crashes with a Segmentation fault and I get a oops in the messages file (see attachment). I tried ksymoops on this file, but either I did something wrong or it couldn't analyse it.

I hope, this issue will be fixed soon cause I would like to switch over to the 2.4 kernel series without scratching my set of MO-disks.

Regards
Detlev

Btw, please answer by email as well because I think I got removed from the mailing list somehow (or is it that quiet?).

Detlev Offenbach
[email protected]

Jul 21 14:38:21 majestix kernel: Unable to handle kernel NULL pointer dereference at virtual address 00000000
Jul 21 14:38:21 majestix kernel:  printing eip:
Jul 21 14:38:21 majestix kernel: 00000000
Jul 21 14:38:21 majestix kernel: *pde = 00000000
Jul 21 14:38:21 majestix kernel: Oops: 0000
Jul 21 14:38:21 majestix kernel: CPU:    0
Jul 21 14:38:21 majestix kernel: EIP:    0010:[<00000000>]
Jul 21 14:38:21 majestix kernel: EFLAGS: 00010282
Jul 21 14:38:21 majestix kernel: eax: 00000000   ebx: d729dcc0   ecx: 00004000   edx: d729dce0
Jul 21 14:38:21 majestix kernel: esi: 40017000   edi: 00000000   ebp: 00004000   esp: d727ff80
Jul 21 14:38:21 majestix kernel: ds: 0018   es: 0018   ss: 0018
Jul 21 14:38:21 majestix kernel: Process more (pid: 1191, stackpage=d727f000)
Jul 21 14:38:21 majestix kernel: Stack: e2bad8fd d729dcc0 40017000 00004000 d729dce0 d729dcc0 ffffffea c012e156 
Jul 21 14:38:21 majestix kernel:        d729dcc0 40017000 00004000 d729dce0 d727e000 08050b68 08050b68 bffff49c 
Jul 21 14:38:21 majestix kernel:        c0106c2b 00000003 40017000 00004000 08050b68 08050b68 bffff49c 00000003 
Jul 21 14:38:21 majestix kernel: Call Trace: [sys_read+150/208] [system_call+51/56] 
Jul 21 14:38:21 majestix kernel: 
Jul 21 14:38:21 majestix kernel: Code:  Bad EIP value.

You might try the -ac series. I recall 2048 byte blocks being implemented in its version of vfat (which is likely the problem you're hitting). Perhaps that particular patch hasn't made it to Linus' tree, yet.

-Steven
In a time of universal deceit, telling the truth is a revolutionary act.
			-- George Orwell

Does anyone know if patches exist against the stock RedHat 7.1 kernel(2.4.2-2) to support remote kernel debugging(kgdb). I would also be interested in the same for kdb, but I'm primarily interested in kgdb.

If it doesn't exist I guess I will have to try to port the patches over myself, I just didn't want to reinvent the wheel.

hopefully TIA,
michael

just in case you are wondering where to download kgdb from, there is one maintained at sourceforge by Amit Kale

http://kgdb.sourceforge.net/

Hi,

I am not maintaining a kgdb patch for RH7.1 as yet. This is an extact from the newly uploaded FAQ page on kgdb website.

Why only one kernel version is supported?
I enhance kgdb and add documentation to kgdb webpage frequently. This process is easy with a single kernel version as I can work on enhancing and supporting newer kernel versions at the same time. I myself need kgdb for kernel debugging on newer kernels for the translation filesystem. Supporting older kernels involves backporting enhancements and testing them. Usually a kgdb patch works for multiple kernel versions with a bit of application of failed hunks by hand. I plan to support a fixed 2.4 kernel version and a top of the line 2.5
kernel, once 2.5 kernel branch starts.

Amit Kale
Veritas Software ( http://www.veritas.com )

Look in the src.rpm for the kernel, there's a ikd patch there...

ftp://oss.sgi.com/projects/xfs/download/Release-1.0/patches/linux-2.4.2-kdb-04112001.patch.gz is kdb v1.8 against Redhat 7.1. There are no XFS dependencies in that
patch, but kdb and xfs hit a couple of common files so you might need
to resolve some patch failures.

It is a lot easier to start from that patch instead of trying to convert a kdb patch from a standard kernel onto Redhat's kernel. RH took patches from the -ac tree as well which really messed up kdb, it took me several hours to work out whta RH had done to each file, and I had all the kdb patches. AFAICR, the IKD patch in RH 7.1 does not fit correctly.

Correction, that patch is against a standard 2.4.2 kernel. The closest
I could find is ftp://oss.sgi.com/projects/xfs/download/testing/Release-1.0.1-PR3/patches/patch-RH2.4.3-xfs-1.0.1-kdb That is against Rawhide rather than RH 7.1 but it should be fairly
close. So many patches, so little time :(.

Hi,

Is the capacity of your MO disk more than 640M?
In order to clarify a problem, please send the debugging output of FAT.

---------------------- start example --------------------------------

 $ mount -t vfat /dev/sda /mnt -o debug
 $ dmesg | tail
  Type:   Optical Device                     ANSI SCSI revision: 02
Attached scsi removable disk sda at scsi0, channel 0, id 5, lun 0
sym53c875-0-<5,*>: asynchronous.
SCSI device sda: 310352 2048-byte hdwr sectors (636 MB)
sda: Write Protect is off
 sda:
MSDOS: Hardware sector size is 2048
[MS-DOS FS Rel. 12,FAT 16,check=n,conv=b,uid=0,gid=0,umask=022]
[me=0xf8,cs=8,#f=2,fs=1,fl=38,ds=77,de=512,data=85,se=0,ts=310352,ls=2048,rc=0,fc=4294967295]
Transaction block size = 2048
---------------------- end example --------------------------------

Perhaps, your MO disk will have the `ls' of a value smaller than 2048. Logical sector size smaller than device sector size cannot be handled with FAT of 2.4 series.

Thanks.

OGAWA Hirofumi <[email protected]>

Hi!

Try -o loop

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details at http://atrey.karlin.mff.cuni.cz/~pavel/velo/index.html.