Re: SIGFPE handler is naive

On Tue, Aug 14, 2012 at 08:40:06AM -0400, Robert Haas wrote:
> On Tue, Aug 14, 2012 at 6:50 AM, Greg Stark <stark(at)mit(dot)edu> wrote:
> > It is possible to check if the signal was synchronous or was sent from
> > an external process. You can check siginfo->si_pid to see who sent you
> > the signal. I'm not sure checking that and handling it at
> > check_for_interrupts if it's asynchronous is the best solution or not
> > though.
>
> If that's portable it might be an option, but I doubt that it is.

I suspect it is portable. Nonetheless, kill() is not the only SIGFPE source
that ought to produce a PANIC. Library code might trigger the signal, at
which point we cannot assume that elog(ERROR) will leave an acceptable system
state. To call this fixed, we need a whitelist of safe sources, not a
blacklist of bogus sources.

That said, I agree that the effort and risk may be out of proportion.