session_start hangs

Question

since a few hours our server hangs every time you do a session_start.

For testing purposes i created a script which looks like this:

Answer 1

For me, the problem seemed to originate from SeLinux. The needed command was chcon -R -t httpd_sys_content_t [www directory] to give access to the right directory. See https://askubuntu.com/questions/451922/apache-access-denied-because-search-permissions-are-missing