[peruser] interesting peruser problem

Stefan Seufert stefan at seuf.de
Fri Apr 7 13:20:40 MDT 2006

Hi Alex,

> The problem have at Multiplexer, after killing this process apache began
> working normally. We try do strace on this process
> and has only
> strace -p 18271
> Process 18271 attached - interrupt to quit
> poll(
> What all. We are try compiling peruser with gcc-4.1 but has same result.

Did you try to send another request while stracing the multiplexer? It
is supposed to block if no requests come in.

The most likely cause for these segfaults is that you do not specifiy
which user should be used by the vhost serving the request. Make sure
you have a XXX option in each vhost and a corresponding YYY option in
the global config.

If you cannot find anything you might want to post your config, allowing
us to have a look at it.

If there is no problem with the config the most useful piece of
information is always a backtrace of the crash. Here is a short summary
how to get one:

You can also try to get a gdb backtrace by doing the following:
1) Build apache with the -g option. You can do this by typing

# make CCFLAGS=-g

instead of just

# make

when building apache.

2) Start apache as usual. Look at the logs to determinate the PID of the
multiplexer process

3) Attach the debugger using

# gdb /path/to/httpd PID

4) The debugger will attach itself and stop the process. Type "continue"
at the gdb prompt

(gdb) continue

5) Then issue a request to the server using your favorite Browser,
telnet or whatever. If the multiplexer dies gdb should show a message
confirming the segfault and show its prompt. Then you can use the
backtrace command to find out where it crashed:

(gdb) bt full

6) send us the output of your gdb session and we might be able to tell more.


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