Today I compiled and installed the newest PHP 5.2 version (5.2.17). After some tests and running a typical phpinfo() command, I experienced segfaults of Apache:

[notice] child pid 20602 exit signal Segmentation fault (11), possible coredump in /tmp

By following the error log, calling phpinfo() seemed to be the only reason to cause a segfault like this. After running php -v the reason was obvious:

# php -v
This build of "eAccelerator" was compiled for PHP version 5.2.13. Rebuild it for your PHP version (5.2.17) or download precompiled binaries.
PHP 5.2.17 (cli) (built: Jan 29 2011 23:42:02)
Copyright (c) 1997-2010 The PHP Group

It is necessary to recompile eAccelator. But a new ./configure won't do the job, it is necessary to do a make clean before (I ran into the same problem without make clean)! So here we go in the extracted eAccelerator dir:

# make clean
# phpize
# ./configure
# make
# make install

After this I called phpinfo() several times, no crash was detected. And the php -v output looked like this:

# php -v
PHP 5.2.17 (cli) (built: Jan 29 2011 23:42:02)
Copyright (c) 1997-2010 The PHP Group