There is a known issue when Oracle Access Manager components such as WebPass, Policy Manager and WebGates are installed on Oracle HTTP Server.
Typically, while installing the WebPass (say) , the httpd.conf of HTTP Server will be pointed out and after the webpass configurations are updated in the httpd.conf, the Http Server should be restarted.
The below error was encountered in Apache error log while restarting HTTP Server
/u01/osinfra/Apache/Apache/logs/httpd.pid overwritten — Unclean shutdown of previous Apache run?
*** glibc detected *** realloc(): invalid size: 0x0819e4a8 ***
This is because of the perl module in the Apache server.
Edit the httpd.conf and comment the below line.
LoadModule perl_module libexec/libperl.so
Attempt to start the HTTP Server is succesful.