Oct 5 03:39:03 server kernel: grsec: From 188.8.131.52: denied resource overstep by requesting 8392704 for RLIMIT_STACK against limit 8388608 for /usr/sbin/httpd[httpd:6832] uid/euid:48/48 gid/egid:48/48, parent /usr/sbin/httpd[httpd:6806] uid/euid:0/0 gid/egid:0/0
Thank you for the question. The kernel is just reporting that an application exceed a limit you have configured on your system or that the application set for itself. ASL doesnt set these limits, neither does the kernel, the ASL kernel just has the added capability of reporting when a limited has been exceeded. A vanilla kernel does not have the ability to log this, so you wouldn't know this was happening.
So, short answer, a limit you have configured on your system has been exceeded. Either because of a problem with an application wrongly exceeding them, or your limits (or the applications) are too low.
The default limit most vendors set for the stack (with any kernel) is 8MB. You may want to find out why you are overstepping the default limits. Odds are something is wrong with whatever google is accessing (a buggy web app for example) and its cascading out of control, eating up the stack and being killed off so it wont kill the system (and that action is being logged not caused by the kernel). A stack limit being exceeded by apache is a pretty strange thing to happen, so I'd look at your web logs to see if you have bigger issues like its segfaulting, or something is blinding going outside the stack.
In short, this is the application killing itself, and the kernel is just logging it (not causing it). So theres not anything we can do, its an application error with apache. If I had to guess, you probably have a signal 11 (segfault) happening and thats triggering the RLIMIT_STACK limit.