kgdb usage errors on strictly following kgdb authorss guide

[Gilad Ben-Yossef]

Lev Olshvang wrote:

>
> Hello all,
>
> I am looking for explanation of the  kgdb errors and usage advice.
>
> I am running Linux 2.6.15.5 system with a kgdb patches from the 
> kgfb.linsyssoft.com.
>
> I built a kernel with ethernet driver included (not module) and KGDB 
> remote debug enable over Ethernet.
>
> I am trying to strictly follow the guide I had downloaded from 
> linsyssoft.com
>
>
> First I tried to run debug other ethernet using kgdboe parameter on boot
>
> I built a kernel with ethernet driver included (not module) and KGDB 
> remote debug enable over Ethernet.
>
> And the gdb session was stuck because the target system did not 
> answered to ARP requsests
> for 10.0.0.3
> The corresponding section from gub.conf is
>
> title Linux-2.6.15.5-kgdb(eth)
> root (hd0,0)
> kernel /boot/vmlinuz-2.6.15.5-kgdb ro root=/dev/hda1 
> kgdboe=@10.0.0.6/, at 10.0.0.3/
> console=ttyS0,115200
>
>
> So I suppose I should manually load network driver, but how can I do 
> it from boot line and assign IP address to it ?
The answers, as very often with such simple questions, are in the kernel 
documentation directory:

Add 
"ip=<client-ip>:<server-ip>:<gw-ip>:<netmask>:<hostname>:<device>:<autoconf>" 
to the kernel command line. See 
http://lxr.linux.no/linux+v2.6.28.4/Documentation/filesystems/nfsroot.txt#L80 
for the details

> ------------------------------------------------------------------------------------------------------------------- 
>
>
> The second attempt I took with a serial 8250 driver
> I had build new kernel with Serial driver configured  for remote 
> debugging and
>
> changed boot line to :
>
> kernel /boot/vmlinuz-2.6.13-kgdb ro root=/dev/hda1 kgdbwait 
> kgdb8250=1,115200
>
> *Question1 :  - docs says it must be kgdb8250=ttyS1,115200,
> *
> but when I tried this , the debug session even did not come to kgdb 
> breakpoint.
I'm guessing it needs to be ttyS0 and not 1.
>
>
> gdbmod-2.4 ./vmlinux itle Linux-2.6.15.5-kgdb(eth)
>
>
> GNU gdb 6.4
> Copyright 2005 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"...Using host 
> libthread_db library "/lib/libthread_db.so.1".
>
> (gdb) set remotebaud 115200
> (gdb) target remote /dev/ttyS0
> Remote debugging using /dev/ttyS0
> breakpoint () at kernel/kgdb.c:1888
> 1888            atomic_set(&kgdb_setting_breakpoint, 0);
> (gdb) cont
> Continuing.
> [17179569.184000] Waiting for connection from remote gdb...
> [*17179569.184000] Invalid syntax for option kgdb8250=*
>
> [New thread 1737]
> Error while mapping shared library sections:
> ide_disk.ko: Success.
> Error while reading shared library symbols:
> ide_disk.ko: No such file or directory.
> Error while reading shared library symbols:
> ide_disk.ko: No such file or directory.
> [New thread 1774]
> Error while reading shared library symbols:
> ide_disk.ko: No such file or directory.
> Error while reading shared library symbols:
> ide_disk.ko: No such file or directory.
> [New thread 1747]
> Error while mapping shared library sections:
> generic.ko: Success.
> Error while reading shared library symbols:
> ide_disk.ko: No such file or directory.
> Error while reading shared library symbols:
> generic.ko: No such file or directory.
> Error while reading shared library symbols:
> ide_disk.ko: No such file or directory.
> Error while reading shared library symbols:
> generic.ko: No such file or directory.
> [New thread 1757]
> Error while mapping shared library sections
>
> Question 3 : Are those Succeses and Errors normal
No. I think you are missing the path to where the target kernel modules 
are. It should something like

set solib-absolute-prefix /dev/null
set solib-search-path /path/to/kernel/modules
> Question  4: How I can command to load my module from gdb line and set 
> a breakpoint to the function I would like to debug ?
>
Just load your modules on the target and then break in gdb and plant the 
break point. you can also plant a break point before loading the module 
(a defered break point) if you want to break in the module init function.\


Gilad
>
>
> Regards to the kenel gurus.
>
> Lev
>
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>


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Gilad Ben-Yossef 
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