PHP Fatal error: require(): unable to unlock pthread lock

Question

I'm using LAMP on Debian Linux. Apache 2.2.22-12, PHP 5.4.4.

Sometimes I get this error and then i couldn't reload page or open pages, which includes file with this error. After I've got such error i couldn't restart apache

Restarting web server: apache2(98)Address already in use: make_sock: could not bind to address [::]:80

(98)Address already in use: make_sock: could not bind to address 0.0.0.0:80 no listening sockets available, shutting down

Unable to open logs

Action 'start' failed.

The Apache error log may have more information. failed!

In apache log file:

[Wed Nov 21 15:07:55 2012] [warn] child process 4020 still did not exit, sending a SIGTERM

[Wed Nov 21 15:07:55 2012] [warn] child process 4021 still did not exit, sending a SIGTERM

[Wed Nov 21 15:07:55 2012] [warn] child process 4022 still did not exit, sending a SIGTERM

[Wed Nov 21 15:07:57 2012] [error] child process 1309 still did not exit, sending a SIGKILL

[Wed Nov 21 15:07:57 2012] [error] child process 1310 still did not exit, sending a SIGKILL

[Wed Nov 21 15:07:57 2012] [error] child process 1311 still did not exit, sending a SIGKILL

And host log:

[Wed Nov 21 12:21:24 2012] [error] [client 127.0.0.1] PHP Fatal error: require(): unable to unlock pthread lock in ~/www/yii/yii-1.1.11.58da45/framework/base/CApplication.php on line 127

There is

$config=require($config);

Or:

[Wed Nov 14 21:04:26 2012] [error] [client 127.0.0.1] PHP Fatal error: require_once(): unable to unlock pthread lock in ~/projects/politiya/index.php on line 14

There is:

require_once($game_loader);

---

I've deleted php-apc and now lamp works good.

Answer 1

Fix

As mentioned here, I had to quickly uninstall and reinstall apc (literaly takes 5s):

1 sudo pecl uninstall apc

2 sudo pecl install apc

BUT change the no which is already filled in for pthread mutexes into a yes

AND change the yes which is already filled in for pthread read/write locks into a no.

Answer 2

This error happens because of a 'deadlock bug' in APC. A php bug report page says that, this bug is fixed in APC 3.1.8

Also we can see the APC change logs here

Answer 3

Just an FYI (in response to OMG's comment about APC version bug), I'm running APC 3.1.13 and PHP 5.4.17 and I still got the bug:

unable to obtain pthread lock (EDEADLK)