From mboxrd@z Thu Jan  1 00:00:00 1970
From: thayumker@gmail.com (Thayumanavar S)
Date: Wed, 11 May 2011 07:49:24 +0530
Subject: Seeing symbols of modules in kgdb setup
In-Reply-To: <20110510200019.GH5513@trikaliotis.net>
References: <20110510200019.GH5513@trikaliotis.net>
Message-ID: <BANLkTimFPHwgAarj1dMDVTci9Be8XSAVGA@mail.gmail.com>
To: kernelnewbies@lists.kernelnewbies.org
List-Id: kernelnewbies.lists.kernelnewbies.org

> I think the tutorial on Linsyssoft helped me a lot (but only after
> combining it with other resources): http://kgdb.linsyssoft.com/quickstart.htm.
>
> I have built a custom kernel with kgdb. kgdboc and kgdbwait are set up,
> I can break into my machine over serial. I can single step through the
> kernel, as long as no modules are involved.
>
> As soon as I have a module, I do not see its symbols or source anymore.
> http://kgdb.linsyssoft.com/downloads.htm mentions a modified "gdbmod",
> which has additional functionality to allow this.
You can use add-symbol-file to add symbol information to your modules.
Say as an example,
add-symbol-file /home/myhome/mymod.ko <text-address> -s .data
<data-address> -s .bss <bss-address>.
You can get the text-address, data-address, bss-address of the module
where it is loaded ( after loading the module) via:
cat /sys/module/mymod/sections/.text
cat /sys/module/mymod/sections/.data
cat /sys/module/mymod/sections/.bss
Recent kernel versions contain kgdb as part of the mainline kernel and
no need to apply any kernel patches if you use this kernel.

Thanks,
Thayumanavar S.