apache hangs in wait4

[Ivan Voras]

Hello,

I have a very embarrassing problem where apache22-worker, running
mod_fcgid with php, perl and python fastcgi processes, hangs daliy in wait4:

# procstat -k 54688
  PID    TID COMM             TDNAME           KSTACK
54688 101355 httpd            -                mi_switch
sleepq_catch_signals sleepq_wait_sig _sleep kern_wait sys_wait4
amd64_syscall Xfast_syscall

The only suspicious things in logs is this:

[Sat Jul 07 20:00:01 2012] [notice] SIGUSR1 received.  Doing graceful
restart
[Sat Jul 07 20:00:10 2012] [error] FastCGI process 41228 still did not
exit, terminating forcefully

The 41228 process is a Perl FastCGI web application using p5-FCGI
(wwsympa), and it is in the accept wchan.

Any ideas?