[TUHS] self-reproducing programs

Random832 random832 at fastmail.com
Fri Mar 25 00:41:54 AEST 2016

On Thu, Mar 24, 2016, at 10:24, Tony Finch wrote:
> There was only ever one instance of the
> program running, but its pid changed hundreds of times per second.
> Since it had daemonized, I couldn't use process groups to kill it.
> Since it was running as root, I couldn't use `kill -TERM -1` to kill just
> one user's processes.
> Since it was a production server, I reslly didn't want to reboot.
> I tried picking a pid somewhat larger than the program's rapidly
> increasing pid, and ran a script: while !kill $pid; do :; done

Out of a curiosity, if a C program executes kill(-1, SIGSTOP), will it
itself be stopped? Or can SIGSTOP be ignored?

If so, maybe you could have solved it by stopping everything and then
continuing everything but the offending program. Of course, then you
risk that other programs on the system may have side effects from being
stopped and continued (interrupted system calls they may not be able to
handle, etc)

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