Re: analysing a coredump

On 2023-11-29, void <void@f-m.fm> wrote:
> Hi,
>
> httpd had an unexpected coredump. I installed gbd and with
> what little i know of it, ran gdb against the dump:
>
> (gdb) core /httpd.core
> [New LWP 101030]
> Core was generated by `/usr/local/sbin/httpd -DNOHTTPACCEPT'.
> Program terminated with signal SIGSEGV, Segmentation fault.
> Address not mapped to object.
> #0  0x000000083f237930 in ?? ()
> (gdb) bt full
> #0  0x000000083f237930 in ?? ()
> No symbol table info available.
>
> (goes on like this for another 10 lines)
>
> I *guess* [1] I'll need to recompile apache24 with debug symbols then 
> wait for another crash. Is there anything else i can do regarding this problem?
>
> [1] gdb etc aren't my wheelhouse *at all* but i'm willing to learn, and any 
> tips/pointers would be much appreciated, thanks

Hi, there are certainly people here who are doing such regularly.
I am only doing it when a bug hits me. I recommend recompiling with
debug symbols, and also setting -O0 (because otherwise many
interesting things get "optimized away").

Then a backtrace should give proper locations to be found in the
source, and probably understood from there.

Since I cannot remember the options, I coded them into my build
engine, as such:
https://gitr.daemon.contact/sysup/commit/?id=3e15a711236c90ac9d525b83d1388cb8e4e1141d
Adding these options to make.conf has worked for me (but may depend on how
the port is designed).

Also there is a "lldb" command on the system, which may or may not
give better results, anyway that has elaborate features.

cheerio & good luck!