Apparently this can be caused by something like logrotate sending many "reload" signals to apache in quick succession:
<https://access.redhat.com/solutions/2626601> I experienced such an apache crash this morning when the logs were rotated. I've now adjusted my logrotate config to only reload apache once (despite many sections for different web site's logs, some of which have specifically different user/group settings for the files) and will see if that avoids another crash tomorrow.
