root process tries to kill child, but fails.

[Rocco]

Binary package hint: apache2

Gutsy apache2-mpm-prefork 2.2.4-3build1

The main process running as root tries to kill of child but fails. An strace -p of the root process shows:

wait4(13592, 0x7fff831e8c3c, WNOHANG|WSTOPPED, NULL) = 0
wait4(13593, 0x7fff831e8c3c, WNOHANG|WSTOPPED, NULL) = 0
wait4(13522, 0x7fff831e8c3c, WNOHANG|WSTOPPED, NULL) = 0
wait4(13524, 0x7fff831e8c3c, WNOHANG|WSTOPPED, NULL) = 0
wait4(13592, 0x7fff831e8c5c, WNOHANG|WSTOPPED, NULL) = 0
kill(13592, SIG_0) = 0
rt_sigprocmask(SIG_BLOCK, [CHLD], [], 8) = 0
rt_sigaction(SIGCHLD, NULL, {SIG_DFL}, 8) = 0
rt_sigprocmask(SIG_SETMASK, [], NULL, 8) = 0
nanosleep({1, 0}, {1, 0}) = 0
wait4(13592, 0x7fff831e8c3c, WNOHANG|WSTOPPED, NULL) = 0
wait4(13593, 0x7fff831e8c3c, WNOHANG|WSTOPPED, NULL) = 0
wait4(13522, 0x7fff831e8c3c, WNOHANG|WSTOPPED, NULL) = 0
wait4(13524, 0x7fff831e8c3c, WNOHANG|WSTOPPED, NULL) = 0
wait4(13592, 0x7fff831e8c5c, WNOHANG|WSTOPPED, NULL) = 0
kill(13592, SIG_0) = 0
rt_sigprocmask(SIG_BLOCK, [CHLD], [], 8) = 0
rt_sigaction(SIGCHLD, NULL, {SIG_DFL}, 8) = 0
rt_sigprocmask(SIG_SETMASK, [], NULL, 8) = 0
nanosleep({1, 0}, <unfinished ...>
Process 32521 detached

The child lives on:
ps aux | grep 13592
www-data 13592 0.0 1.1 347084 37144 ? S Nov09 0:00 /usr/sbin/apache2 -k start

This is a serios problem since childs never gets killed and it will take more and more memory on the server, when more and more childs are started and never killed off. Server listens to both 80 and 443.