signal delivered to a different process?

[Richard Chen]

This is pretty weird situation. I have installed a signal
handler in startup.pl which showed that the signal is
delivered to a different process!

Here are the demo files:

$ cat conf/startup.pl
#!/usr/local/bin/perl
use lib '/usr/local/apache/modules';
$SIG{USR2}=sub {
        print STDERR "Received USR2 signal:\n";
        print STDERR "In SIG, pid=$$, ppid=".getppid()."\n";
};

# cat /usr/local/apache/modules/Apache/ChildInit.pm
package Apache::ChildInit;
sub handler {
        print STDERR "In ChildInit, pid=$$, ppid=".getppid()."\n";
        return;
}
1;

In httpd.conf I have these 2 lines added:
        PerlRequire conf/startup.pl
        PerlChildInitHandler Apache::ChildInit

After launching the modperl process we have:

$ ps -ef|grep http|grep root
root      5964     1  0 16:17 ?        00:00:00 /usr/local/apache/bin/httpd

$ tail -1 error_log
In ChildInit, pid=5965, ppid=5964

So the modperl parent process has pid 5964.
After sending USR2 signal to the modperl parent process, 
these lines appear in the error_log file:
        Received USR2 signal:
        In SIG, pid=5963, ppid=1

So the signal is delivered to the process 5963 instead of the correct 5964.

Has anyone seen this before?
Is this a bug in modperl or if the procedure for installing the handler 
is incorrect?

I used 
        Apache/1.3.17 (Unix) mod_perl/1.25 mod_ssl/2.8.0 OpenSSL/0.9.6
on a linux 6.1 box.

Thanks for any info.

Richard