[CentOS] httpd stopped working under SELinux so I had to turn SELinux off. libxml2.so.2: failed to map segment from shared object: Permission denied

Hi.

CentOS 5.4 64-bit with SELinux, happily running for over a year, suddenly
httpd fails to start up, getting an error message like:

Starting httpd: Syntax error on line X of /etc/httpd/conf.d/php.conf:
Cannot load /etc/httpd/modules/libphp5.so into server: libxml2.so.2:
failed to map segment from shared object: Permission denied

I turned off SELinux and was able to start httpd.

But what went wrong?  And how to fix it and turn SELinux back on?

SElinux labels on libxml.so.2.6.26 are OK ( system_u:object_r:lib_t )
and "restorecon -n libxml.so.2.6.26" does not return anything.

No recent AVC denied entries in /var/log/audit/audit.log or /var/log/messages.

I googled the above error message but all I could find were web pages in Chinese
advising to run restorecon on libxml2.so file or turn off SElinux.

Any suggestions?

Thanks
Aleksey