Debugging the linux kernel core dump

From: gmate.amit@gmail.com (amit mehta)
To: kernelnewbies@lists.kernelnewbies.org
Subject: Debugging the linux kernel core dump
Date: Fri, 5 Aug 2011 12:16:22 +0530	[thread overview]
Message-ID: <CAOUxTKMChnch45asNEBogzKCdX5aNA-0CJY=Hbdao0C4O5=YEQ@mail.gmail.com> (raw)
In-Reply-To: <CAN1N8TiQNFfEh68=dt8FUDzud=p7Ae62u9d8TdfGNWg-bihzzA@mail.gmail.com>

On Fri, Aug 5, 2011 at 10:53 AM, Akash <email2akashjain@gmail.com> wrote:
> I think it was not built with -g otherwise the symbols would have been there
> in the vmlinux itself, right ?
Right.
> That is the reason I need to add symbols externally.
> Please dont ask me to rebuild the kernel, this is vanilla OpenSUSE 11.3
> symbols and debug kernel should be available somewhere. I just need to know
> how/where to add the symbols. The problem is not reproducible, I need to
> debug the core which I have on hand.
>
> Thanks.
> Akash
>
I "think" System.map file is not the file which gbd understands , On
my system, i tried this:
goon:/boot # gdb -q
(gdb) symbol-file System.map-2.6.32.12-0.7-default -readnow
`/boot/System.map-2.6.32.12-0.7-default': can't read symbols: File
format not recognized.

I might be missing something else as well.

-Amit

>
> On Thu, Aug 4, 2011 at 10:19 PM, amit mehta <gmate.amit@gmail.com> wrote:
>>
>> Not sure about the symbol table, but was your kernel compiled
>> with -g flag (-g to the CFLAGS variable in the kernel Makefile) ?
>>
>> -Amit
>>
>> On Fri, Aug 5, 2011 at 10:42 AM, Akash <email2akashjain@gmail.com> wrote:
>> > Hello,
>> >
>> > I have a core dump from following machine :
>> >
>> > # uname -a
>> > Linux sing-vto2-dst 2.6.34.8-0.2-desktop #1 SMP PREEMPT 2011-04-06
>> > 18:11:26
>> > +0200 x86_64 x86_64 x86_64 GNU/Linux
>> >
>> > I have opened this core in gdb
>> >
>> > # gdb vmlinux-2.6.34.8-0.2-desktop kernel.core0
>> > GNU gdb 6.6 (build 2009-10-05)
>> > Copyright (C) 2006 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.
>> > (no debugging symbols found)
>> > Program terminated with signal 11, Segmentation fault.
>> > #0? 0xffffffff8100ba60 in default_idle ()
>> >
>> >
>> > How can I add symbols to gdb ?
>> > When I try to add symbols from System.map I get following error :
>> >
>> > (gdb) add-symbol-file System.map-2.6.34.8-0.2-desktop
>> > The address where System.map-2.6.34.8-0.2-desktop has been loaded is
>> > missing
>> >
>> >
>> > At what address should the System.map be added ? How can I find out that
>> > address ?
>> >
>> > Thanks for any help.
>> >
>> > Akash
>> > _______________________________________________
>> > Kernelnewbies mailing list
>> > Kernelnewbies at kernelnewbies.org
>> > http://lists.kernelnewbies.org/mailman/listinfo/kernelnewbies
>> >
>> >
>
>