Subject: fdisk/kernel oddity

From: Guido Guenther <[email-masked]>
Date: Wed, 25 Oct 2000 19:01:29 +0200

Hi,
I recently partitioned a second HD on an Indy with Keith's fdisk patch.
After some writing to it( cp -a /usr /mnt), I see the following:
Oct 25 16:00:37 bert kernel: 08:11: rw=0, want=1088320776, limit=533919
Oct 25 16:00:37 bert kernel: attempt to access beyond end of device
[..snip..]   
Oct 25 16:00:37 bert kernel: 08:11: rw=0, want=138373542, limit=533919
Oct 25 16:01:27 bert kernel: [rm:9357] Illegal instruction at 004059a4 ra=004028d8

08:11 is /dev/sda11 which is the "SGI volume", according to fdisk -l:
  Device  Info      Start       End   Sectors  Id  System
  /dev/sda1  boot         6       937   3872540  83  Linux native
  /dev/sda2  swap       938      1009    298850  83  Linux native
  /dev/sda9               0         4     20770   0  SGI volhdr
  /dev/sda11              0      1008   4191386   6  SGI volume

So the requsted block is *far* out of bounds.

What puzzles me even more is that I get illegal instructions for almost 
all commands I execute afterwards. Any comments on this one?
Regards,
 -- Guido

-- 
GPG-Public Key: finger [email-masked]

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From: Keith M Wesolowski <[email-masked]>
Date: Wed, 25 Oct 2000 10:14:53 -0700

> Oct 25 16:01:27 bert kernel: [rm:9357] Illegal instruction at 004059a4 ra=004028d8

Not to sound defensive, but I'm fairly sure this isn't an
fdisk-related problem. The partitions that fdisk creates follow the
spec as far as I can see.

> So the requsted block is *far* out of bounds.

These partitions look quite sane. I wonder, though, if there's
something about your specific partitioning that is confusing the
kernel's SGI disklabel support.

> all commands I execute afterwards. Any comments on this one?

I rather suspect that this is the same problem that causes the request
for the out-of-bounds block in the first place: kernel memory
corruption. Unfortunately I have few ideas as to what the specific
problem is. I would start bug-hunting in the sgi disklabel kernel
parts. Make sure that it's compatible with what fdisk is doing.

-- 
Keith M Wesolowski			[email-masked]
University of Nevada			http://www.chem.unr.edu
Chemistry Department Systems and Network Administrator

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From: Guido Guenther <[email-masked]>
Date: Wed, 25 Oct 2000 19:43:48 +0200

> spec as far as I can see.
I didn't want to blame fdisk for that(how could I, I want you to send
the patches upstream ASAP :)
> parts. Make sure that it's compatible with what fdisk is doing.
That's a starting point - thanks. Ian pointed out that it might be
related to the fact that I use two harddisks which is interesting since
I see the problems only when writing on sda, sdb seems to be o.k.
Regards,
 -- Guido

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From: Klaus Naumann <[email-masked]>
Date: Wed, 25 Oct 2000 22:46:12 +0200 (CEST)

> I see the problems only when writing on sda, sdb seems to be o.k.

This is a problem which I'm seeing for a loooooong time now.
I've been geeting this correuption a while back too - look at the mailing
list archives. The problem seems to be cache corruption as far as I can
see. Since Ralf checked in some small fixes for the cache handling it's a
bit better - but not completely fixed.
The Problem is also tracked on the buc tracker btw (#5) .

I have seen this only when copying from one harddisk to another.
Especialy if one wants to copy the kernel sources it will messup.

	CU, Klaus

-- 
Full Name   : Klaus Naumann     | (http://www.mgnet.de/) (Germany)
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Phone / FAX : ++49/177/7862964  | E-Mail: ([email-masked])
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From: Guido Guenther <[email-masked]>
Date: Thu, 26 Oct 2000 00:32:56 +0200

> bit better - but not completely fixed.
Can you explain in what sense it is "a bit better" now. 
> The Problem is also tracked on the buc tracker btw (#5) .
Ian was so kind to but it into the BTS after he told me that this is a
known problem. 
> Especialy if one wants to copy the kernel sources it will messup.
I also see problems when dd'ing from /dev/sda to e.g. /dev/null, 
so this does not only occur when copying between disks. Also in this
case I don't get the illegal instructions but rather strange
"/etc/shadow file not found" messages.
Regards,
 -- Guido

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From: Florian Lohoff <[email-masked]>
Date: Thu, 26 Oct 2000 14:19:08 +0200

> parts. Make sure that it's compatible with what fdisk is doing.

I agree here - This also would fit to the "Illegal Instruction" thing
he sees afterwards - It seems to be time to debug the kernel SGI Disklabel
support :)

Most interestingly i am running on an Indigo2 with 7 Disks attached 
and they all have SGI Disklabels - And i have no problems (Although
6 of the 7 have the exatly same geometrie)

Flo
-- 
Florian Lohoff		[email-masked]		      	+49-5201-669912
      "Write only memory - Oops. Time for my medication again ..."