Bug#219378: Further info
I once again tried to upgrade to the latest apache (now 126.96.36.199.1-5) and
still found this behavior. However, I managed to discover that the thing
that was hanging the apache processes was actually logrotate stuck in a
write() call that never returns. This behavior never happened with apache
1.3.28 and I have the most recent logrotate installed. Configuring apache
to not use logrotate and to log itself caused this behavior to stop.
I still consider this a bug in apache but have no further specifics to
offer at this time.