[PATCH] Increase fork signal safety for single-threaded processes [BZ #19703]

[Florian Weimer]

On 05/11/2016 09:59 PM, Tulio Magno Quites Machado Filho wrote:
> I suggest to fork the SIGUSR2 sender first.
> Sometimes the SIGUSR1 sender floods the parent to the point it takes seconds
> to fork the second sender.

I believe this is a different issue: sigusr1_sender_pid may be 0 if 
SIGUSR1 arrives very early, and we send SIGSTOP to the current process 
group, not just the subprocess.  This is consistent with no output at 
all from the test program (which is what I saw in this case).

I will commit a fix for this test issue shortly.

Florian