Re: Two gdb 6.4 usage queries

[Jon Grant <jg at jguk dot org>]

Hi Mark,

Thanks for your reply with suggestions.

Mark Kettenis elucidated on 11/11/06 22:28:
>>  Hello,
>>
>>  Don't think I missed any reply.. I wonder if anyone could help me with
>>  some info on how solve the problems?
> 
> For one thing, those backtraces do not correspond to the same state.
> I don't know what the kde crash handler is doing, but it might be worth
> trying to disable it, such that your program just crashes.  The resulting
> core dump should be easier to interpret.  And if it isn't, you probably
> need to install the appropriote debug info packages for your system.

That sounds good. I've not noticed "core" files being dumped since I
switched to Kubuntu, do you know if I have to enable something somewhere
to get them?

>>> Attaching to program: /usr/bin/ark, process 6582
>>> (no debugging symbols found)
> 
> Do yourself a favour, and compile your code (all of it) with -g.

Unfortunately these are the binaries shipped with Kubuntu from KDE

>>> 0xffffe410 in __kernel_vsyscall ()
>>> (gdb) bt
>>> #0  0xffffe410 in __kernel_vsyscall ()
>>> #1  0xb7d09110 in ?? ()
>>> #2  0xb7d08f3c in ?? ()
>>> #3  0xbfc11bb4 in ?? ()
>>> #4  0xbfc11bb4 in ?? ()
>>> #5  0x00000000 in ?? ()
> 
> Make sure you install at least the debug info packages for glibc.

I really wish Kubuntu 6.06 had such packages, would make it a lot
simpler trying to give feedback on crashes.

Perhaps I shouldn't bother filing bugs until they start shipping binaries
which can produce useful backtraces out-of-the-box. The crashes are nearly
always not reproducible unfortunately.

I managed to find the bit of info I needed "frame n" and "show address"
which allowed me to calculate the position in the disassembled file I
got from objdump. GDB doesn't demangle symbols it seems too. Do you know
if it
only attempts to demangle using debug sections?

Please include my email address in any replies as I'm not a member of
this list.

Thanks for your help, Kind regards
Jon