Can a process be stopped via a systemtap probe so gdb can be attached?

Question

We have a multi-process application where debugging a specific child process is proving difficult. Due to messaging timeouts between the processes we don't have time to attach gdb to the target child, so I was wondering if I can stop a process via an systemtap probe?

A simple probe should, I think, be needed, eg.:

probe process("exeName").mark("STOP_HERE")
{
    force_sig(SIGSTOP, current);
}

Unfortunately, the above's not compiling ... any ideas?

---

I'm not a systemtap expert, so this isn't probably the best solution, but here's my crude solution for anyone interested:

#!/bin/stap -g

global gdbRunning = 0;

probe process(@1).mark(@2)
{
    raise(%{ SIGSTOP %});

    gdbCmd = sprintf("cgdb -- -q -ex 'thread find %d' %s %d", tid(), @1, pid());

    if (gdbRunning == 0)
    {
        gdbRunning = 1;
        printf("STOP PID %d TID %d [%s]\n", pid(), tid(), gdbCmd);
        system(gdbCmd);
    }
    else
    {
        printf("STOP PID %d TID %d\n", pid(), tid());
    }
}

Answer 1

See man function::raise(3stap), new as of systemtap 2.3 (2013-07-25).

stap -g -e 'probe WHATEVER { raise(%{ SIGSTOP %}) }'

You need guru mode to let your script use this function.