[Crash-utility] how to analyze a 32bit dump with a 64bit crash

Wright, David dwright at egenera.com
Tue Mar 27 15:46:23 UTC 2007


Hi Dave,

This seemed like the perfect opportunity to ask if this proves
there might be a market for my cross-compilation additions to
crash. 

Not the byte-swapping stuff.  The lack of hosannas from your
end has caused me to tearfully conclude that I didn't make the
cut.

So let me propose a couple of things:

1)  How about if I just submit my diffs that allowed for
    cross-compilation of the x86 version on a 64-bit platform?
    Plus any bug fixes or other minor amendations I had?

2)  I might have a better solution to this whole "how to do
    byte-swapping, where needed, without confusing everything
    in sight?"  A partial solution, anyway.

    The model would be based on the difference between malloc
    and calloc calling sequences.  With malloc, you just specify
    the length you want.  With calloc, you specify a number of
    items and the length of each item.

    We could have a readmem variant that incorporates the calloc
    style.  Don't specify a length, specify an item count and an
    item length.  Then the byte swappers could hook into this,
    but ordinary code would still do a readmem-style thing.  
    Would this be any better?

Regards,

  -- David "that's a little more information than I needed" Wright
 

> -----Original Message-----
> From: crash-utility-bounces at redhat.com 
> [mailto:crash-utility-bounces at redhat.com] On Behalf Of Dave Anderson
> Sent: Tuesday, March 27, 2007 11:29 AM
> To: blackmagic02881 at gmail.com
> Cc: Discussion list for crash utility usage, maintenance and 
> development
> Subject: Re: [Crash-utility] how to analyze a 32bit dump with 
> a 64bit crash
> 
> Ming Zhang wrote:
> 
> > On Tue, 2007-03-27 at 10:17 -0500, Dave Anderson wrote:
> > > Ming Zhang wrote:
> > > > Hi All
> > > >
> > > > My laptop has 64bit fc6 and crash utility. One of the 
> development
> > > > machine is 32bit RHEL4. whenever i try to open the dump 
> generated
> > > > by
> > > > that box, I got a unknown format error. i can analyze 
> the dump with
> > > > the
> > > > crash from that RHEL4, and also my laptop can analyze 
> the dump from
> > > > another 64bit RHEL4.
> > > >
> > > > so my question is how to allow the crash in a 64bit box 
> to open a
> > > > dump
> > > > from a 32bit box?
> > > >
> > > > Thanks!
> > > >
> > > > Ming
> > > >
> > > >
> > > >
> > > Try copying a 32-bit crash utility to the 64-bit laptop,
> > > and running it from there.
> >
> > i thought about this. could u enlighten us why single crash 
> cannot do
> > that? implementation limitation or more deeper reason?
> >
> 
> Most definitely an implementation limitation.  The source only
> builds in the machine-specific source code based upon the
> host machine type.
> 
> >
> > >
> > > Here's an example:
> > >
> > > # uname -m
> > > x86_64
> > > # file ./crash
> > > ./crash: ELF 32-bit LSB executable, Intel 80386, version 
> 1 (SYSV), for
> > > GNU/Linux 2.2.5, dynamically linked (uses shared libs), 
> not stripped
> > > # ./crash /tmp/vm*
> > >
> > > crash 4.0-3.21
> > > Copyright (C) 2002, 2003, 2004, 2005, 2006, 2007  Red Hat, Inc.
> > > Copyright (C) 2004, 2005, 2006  IBM Corporation
> > > Copyright (C) 1999-2006  Hewlett-Packard Co
> > > Copyright (C) 2005, 2006  Fujitsu Limited
> > > Copyright (C) 2006, 2007  VA Linux Systems Japan K.K.
> > > Copyright (C) 2005  NEC Corporation
> > > Copyright (C) 1999, 2002  Silicon Graphics, Inc.
> > > Copyright (C) 1999, 2000, 2001, 2002  Mission Critical Linux, Inc.
> > > This program is free software, covered by the GNU General Public
> > > License,
> > > and you are welcome to change it and/or distribute copies 
> of it under
> > > certain conditions.  Enter "help copying" to see the conditions.
> > > This program has absolutely no warranty.  Enter "help 
> warranty" for
> > > details.
> > >
> > > GNU gdb 6.1
> > > Copyright 2004 Free Software Foundation, Inc.
> > > GDB is free software, covered by the GNU General Public 
> License, and
> > > you are
> > > welcome to change it and/or distribute copies of it under certain
> > > conditions.
> > > Type "show copying" to see the conditions.
> > > There is absolutely no warranty for GDB.  Type "show warranty" for
> > > details.
> > > This GDB was configured as "i686-pc-linux-gnu"...
> > >
> > >       KERNEL: /tmp/vmlinux
> > > DEBUG KERNEL: /tmp/vmlinux-2.4.21-1.1931.2.421.ent.debug
> > >     DUMPFILE: /tmp/vmcore
> > >         CPUS: 1
> > >         DATE: Tue Sep  9 18:02:05 2003
> > >       UPTIME: 05:04:13
> > > LOAD AVERAGE: 9.96, 10.56, 10.89
> > >        TASKS: 72
> > >     NODENAME: moe.lab.boston.redhat.com
> > >      RELEASE: 2.4.21pre1
> > >      VERSION: #3 Tue Sep 9 14:13:17 EDT 2003
> > >      MACHINE: i686  (501 Mhz)
> > >       MEMORY: 128 MB
> > >        PANIC: "Oops: 0002" (check log for details)
> > >          PID: 3701
> > >      COMMAND: "sh"
> > >         TASK: c791c000
> > >          CPU: 0
> > >        STATE: TASK_RUNNING (PANIC)
> > >
> > > crash>
> > >
> > > Dave
> > >
> 
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