Comment 11 for bug 1028470

The issue is in part kernel related
this commit (introduced in 3.2.9) http://git.kernel.org/?p=linux/kernel/git/torvalds/linux.git;a=commitdiff;h=28d82dc1c4edbc352129f97f4ca22624d1fe61de introduced a epoll path limit of 1000 (1000 process listening on the same socket).

This commit (3.2.17) http://git.kernel.org/?p=linux/kernel/git/torvalds/linux.git;a=commitdiff;h=93dc6107a76daed81c07f50215fa6ae77691634f restore the old behavior for non nested epoll path (so you can use unlimited apache process)

Apache shouldn't hang but updating your kernel will solve the issue.
I've opened an apache ticket (https://issues.apache.org/bugzilla/show_bug.cgi?id=54502)