Re: GDB process (on Linux) cooperating with the debugged process (some particular pthread on it)

[Andrew Burgess via Gdb <gdb@sourceware.org>]

Basile Starynkevitch <basile@starynkevitch.net> writes:

> Hello all,
>
> Is it possible for the debugged process (for me the RefPerSys inference engine,
> GPL licensed, see below) which has several threads to send GDB commands or
> interact with the debugger process.

I'm not aware of any existing, general technique for having the debuggee
send commands to the debugger.  There is some limited support for JIT
like processes to allow the process to give GDB debug information for
the dynamically generated code, but nothing beyond that.

>
> This on Linux only (often x86-64, kernel 6.12.27); some event loop of the
> debugged process could run in a particular pthread (which I don't want to debug
> with such a weird GDB).
>
> In general help on debugging a multithreaded Linux process is welcome. Can I
> stop (or GDB step) only one thread and let the others run?

You can turn on non-stop mode with 'set non-stop on'.  In non-stop mode,
when one thread stops, other threads are left running.

HTH
Thanks,
Andrew