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

Ok I face the same problem on 2 PC, 1 is MAC mini XAMPP, 1 is Windows 10 Xampp. Both is php spent infinity to run session_start(). Both PHP version is 7.x.x

I found that session files is lock to read and write. So that I added code to make PHP read session files and immediately unlock when done with

<?php
session_start([
    'read_and_close' => true,
]);
?>

or

<?php
//For PHP 5.x
session_start();

session_write_close();
?>

After this PHP unlock session file => Problems solve

Answer 2

If you use pgAdmin 4 this can happen as well.

If you have File > Preferences > SQL Editor > Options > "Auto Commit" disabled, and you just ran a query using the query tool but didn't manually commit, then session_start() will freeze.

Enable auto commit, or manually commit, or just close pgAdmin, and it will no longer freeze.

Answer 3

To throw another answer into the mix for those going bananas, I had a session_start() dying only in particular cases and scripts. The reason my session was dying was ultimately because I was storing a lot of data in them after a particularly intensive script, and ultimately the call to session_start() was exhausting the 'memory_limit' setting in php.ini.

After increasing 'memory_limit', those session_start() calls no longer killed my script.

Answer 4

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

Answer 5

There are many reasons for that, here are a few of them:

A. The session file could be opened exclusively. When the file lock is not released properly for whatever reason, it is causing session_start() to hang infinitely on any future script executions. Workaround: use session_set_save_handler() and make sure the write function uses fopen($file, 'w') instead of fopen($file, 'x')

B. Never use the following in your php.ini file (entropie file to "/dev/random"), this will cause your session_start() to hang:

<?php
ini_set("session.entropy_file", "/dev/random");
ini_set("session.entropy_length", "512");
?>

C. session_start() needs a directory to write to.

You can get Apache plus PHP running in a normal user account. Apache will then of course have to listen to an other port than 80 (for instance, 8080).

Be sure to do the following things: - create a temporary directory PREFIX/tmp - put php.ini in PREFIX/lib - edit php.ini and set session.save_path to the directory you just created

Otherwise, your scripts will seem to 'hang' on session_start().

Answer 6

In my case it seems like it was the NFS Share that was locking the session , after restarting the NFS server and only enabled 1 node of web clients the sessions worked normally .