[users@httpd] CGI Processes hanging in state "W"

[Steve Swift <st...@gmail.com>]

If we monitor the /server-status page of our apache 2.0.57 running under
linux we notice a build up of processes that are hung in state "W", which is
"Sending Reply":

6-1    13451    1/3/3    W     0.83    1141    0    0.0    0.01    0.01
9.135.165.197    climate.uk.ibm.com    POST /sat/satindex.cmd HTTP/1.1

They are *always* CGI scripts, but the language in which they are written
varies. We have checked the scripts (there are many different ones) and we
can see absolutely no way that the scripts themselves could hang.  In the
simplest scripts there were no loops and nothing that could possibly wait.

I've seen mention of packet loss causing this problem, and while that is a
possibility, we see no other symptoms of packet loss, and anyway, why would
it affect only CGI scripts?

We've been trying to isolate the cause of this, and are just about out of
ideas. Any suggestions on what we might look for?

Is there any mechanism inside apache itself which we could use to terminate
cgi scripts which generate no output after a certain time? This would also
be very useful for scripts that *do* go into a loop during development!

-- 
Steve Swift
http://www.swiftys.org.uk