Intermittent hanging of scripts when loading plugins.php or update-core.php

[ryan.burnette]

When loading plugins.php or update-core.php I am intermittently having the process hang, and the subsequent dump fails. This is happening on multiple sites. All are running WordPress 3.9.

The configuration is the same on each server. Ubuntu 14.04, Nginx 1.6.0 and PHP 5.5.9. I'm using php5-fpm referenced through a .sock. Let me know if I need to provide more detail there.

I changed my PHP settings to log slow requests and this is what appears in the log.

`[07-May-2014 13:19:08] [pool www] pid 5020
script_filename = /srv/staging.mysite.com/wordpress/wp-admin/update-core.php
[0x00007f77aa537b68] fread() /srv/staging.mysite.com/wordpress/wp-includes/class-http.php:1008
[0x00007f77aa5379c0] request() /srv/staging.mysite.com/wordpress/wp-includes/class-http.php:333
[0x00007f77aa5377d8] _dispatch_request() /srv/staging.mysite.com/wordpress/wp-includes/class-http.php:249
[0x00007f77aa537660] request() /srv/staging.mysite.com/wordpress/wp-includes/class-http.php:378
[0x00007f77aa537538] post() /srv/staging.mysite.com/wordpress/wp-includes/http.php:195
[0x00007f77aa537428] wp_remote_post() /srv/staging.mysite.com/wordpress/wp-content/plugins/acf-gallery/acf-gallery-update.php:136
[0x00007f77aa537310] get_remote() /srv/staging.mysite.com/wordpress/wp-content/plugins/acf-gallery/acf-gallery-update.php:165
[0x00007fff2e87c320] check_update() unknown:0
[0x00007f77aa537178] call_user_func_array() /srv/staging.mysite.com/wordpress/wp-includes/plugin.php:192
[0x00007f77aa537000] apply_filters() /srv/staging.mysite.com/wordpress/wp-includes/option.php:1379
[0x00007f77aa536d98] set_site_transient() /srv/staging.mysite.com/wordpress/wp-includes/update.php:253
[0x00007fff2e87c9a0] wp_update_plugins() unknown:0
[0x00007f77aa536bb0] call_user_func_array() /srv/staging.mysite.com/wordpress/wp-includes/plugin.php:470
[0x00007f77aa5369c8] do_action() /srv/staging.mysite.com/wordpress/wp-admin/admin.php:315
[0x00007f77aa536808] +++ dump failed`

Through my troubleshooting I have found that this is not related to a plugin. It happens even when I completely empty the plugins directory.

I want to troubleshoot further to determine if there's a bug or incompatibility here but I'm not sure what to try next.

[ryan.burnette]

I should add the multiple separate servers are exhibiting this behavior. All with similar configurations and completely different subsets of plugins. I have observed this with no plugins installed whatsoever.

[DrewAPicture]

@dd32 or @nacin care to take a look?

[dd32]

Unfortunately this doesn't really provide much of an insight into the issue, and doesn't appear to be a WordPress issue, rather it's a server configuration or PHP incompatibility (as the reporter noted).

I don't think there's anything we can do here, other than agree that this instance of PHP is having problems, most likely during HTTP requests, it could be a PHP bug, a ubuntu bug, or anything else.