A white page in the Magento Admin usually means that the server encountered an internal error of some sort (normally HTTP Status code 500 would be displayed, but most sites disable exception printing to the screen by default).
By default, Magento will disable PHP Fatal Exceptions from being printed to the browser as a security precaution for live production sites, though you can enable it in the Magento Admin (perhaps not right now if you can't see anything but a white page, of course...)
Before proceeding any further, though, it's important to know if you've installed the latest 1.9.1.1 update released on May 1 or the applied the security patch SUPEE-5344 from Magento that address the recently discovered remote code execution vulnerability. Both are availble on the Magento Downloads page.
If you haven't installed them yet, you may want to consider disabling access to the site and / or turning off the web server software to limit futher risk or exposing customer data to the vulnerablility immediately. Then follow the steps outlined here to check for the signature of the exploit on your system.
You can also do a quick check via this handy online tool: http://magento.com/security-patch - note that if you have your Admin configured to force SSL, you may need to use the
As this post points out, his friend saw the same kind of symptom you reported, which would normally just require some digging through logs to see what code is failing, but if you haven't installed the patches above, it may indicate you system has been compromised.
The good news is that it's relatively easy to figure out if you've been compromised and Magento's release some additional guidelines on securing file permisisons of your server installatio...(if you're running Linux / other *Nix like OS).
It's also easy to dig through your logs to identify the source of the problem, but only if you have logging enabled in System > Configuration > Developer > Log Settings : Enabled = Yes
The details you'll need to identify the root cause of the error are going to be stored in one of the following locations on your system (or more than one):
- Apache Logs - large & verbose, include info on all requests to the web servre and the status code returned to the client after responding to the request. May take some time to comb through, and the location varies on different versions of linux, but my Red Hat systems show them in /var/log/httpd :
[user@web /var/log/httpd]# ls -lat
total 1147680
-rw-r--r-- 1 root root 751138867 May 9 23:15 access_log
-rw-r--r-- 1 root root 3681609 May 9 23:15 error_log
-rw-r--r-- 1 root apache 2794970 May 9 23:14 suexec_log
drwxr-xr-x 25 root root 4096 May 9 06:07 ..
-rw-r--r-- 1 root root 711 May 8 10:22 ssl_error_log
The ls command with the -lat flag lists the files most recently updated so you can guess where to start looking (access_log and error_log. Below is an example of using the tail command to print out the last few lines of the file. Your output will differ, but you'll be looking for a GET or POST request and the number printed afterwards - I show 200 because they succeeded but your problem will show 500 indicating an exception.
[user@web /var/log/httpd]# tail access_log
162.104.1.233 - - [09/May/2015:23:18:17 -0500] "GET /js/varien/js.js HTTP/1.1" 200 6335 "http://www.flextonegamecalls.com/fawn-bawl.html" "Mozilla/5.0 (iPad; CPU OS 7_0_6 like Mac OS X) AppleWebKit/537.51.1 (KHTML, like Gecko) GSA/5.1.42378 Mobile/11B651 Safari/9537.53"
162.104.1.233 - - [09/May/2015:23:18:17 -0500] "GET /js/varien/form.js HTTP/1.1" 200 3199 "http://www.flextonegamecalls.com/fawn-bawl.html" "Mozilla/5.0 (iPad; CPU OS 7_0_6 like Mac OS X) AppleWebKit/537.51.1 (KHTML, like Gecko) GSA/5.1.42378 Mobile/11B651 Safari/9537.53"
162.104.1.233 - - [09/May/2015:23:18:17 -0500] "GET /js/varien/menu.js HTTP/1.1" 200 1450 "http://www.flextonegamecalls.com/fawn-bawl.html" "Mozilla/5.0 (iPad; CPU OS 7_0_6 like Mac OS X) AppleWebKit/537.51.1 (KHTML, like Gecko) GSA/5.1.42378 Mobile/11B651 Safari/9537.53"
[user@web /var/log/httpd]# tail error_log
[Sat May 09 23:12:31 2015] [error] [client 188.165.15.234] File does not exist: /var/www/vhosts/default/htdocs/cv_-0-months_cv_Black_pR_0-99_cv_single_mfg_Baby-Planet_Travel-System-Frame.htm
[Sat May 09 23:13:32 2015] [error] [client 66.249.65.23] File does not exist: /var/www/vhosts/default/htdocs/cv_Blue_pR_100-249_cv_single-2_Strollers.htm
PHP Warning: Module 'gnupg' already loaded in Unknown on line 0
PHP Warning: Module 'gnupg' already loaded in Unknown on line 0
PHP Warning: Module 'gnupg' already loaded in Unknown on line 0
[Sat May 09 23:15:04 2015] [error] [client 66.249.82.165] File does not exist: /var/www/vhosts/default/htdocs/images
PHP Warning: Module 'gnupg' already loaded in Unknown on line 0
PHP Warning: Module 'gnupg' already loaded in Unknown on line 0
[Sat May 09 23:16:34 2015] [error] [client 188.165.15.234] File does not exist: /var/www/vhosts/default/htdocs/pR_250-400_cv_double_mfg_Baby-Planet_Lightweight-Strollers.htm
[Sat May 09 23:17:19 2015] [error] [client 66.249.65.19] File does not exist: /var/www/vhosts/default/htdocs/cv_double_mfg_Baby-Planet_cv_3_Strollers.htm
The above is doing the same thing but on the error_log file. You should find some correlation between the timestamps of the entries in this file with the ones showing the 500 response in access_log above it.
Magento System Log : <mage_root>/var/log/system.log
[user@web log]# tail system.log
2015-05-10T04:09:51+00:00 ERR (3): Notice: Undefined variable: storeId in /var/www/vhosts/ardo-usa.com/httpdocs/app/design/frontend/rwd/allium/template/catalog/product/list/related.phtml on line 47
2015-05-10T04:23:35+00:00 ERR (3): Notice: Use of undefined constant OBJECT_TYPE_INFO - assumed 'OBJECT_TYPE_INFO' in /var/www/vhosts/site.com/httpdocs/app/code/community/Strategery/Logger/Model/Observer.php on line 79
Your content will differ, but if you correlate the time stamps of the entries here with the ones from your apache log above, you should find specific info relating to your issue.
Magento Error Log : <magento-root>/var/log/exception.log
[user@web log]# tail -n 20 exception.log
#11 /var/www/vhosts/site.com/httpdocs/app/Mage.php(684): Mage_Core_Model_App->run(Array)
#12 /var/www/vhosts/site.com/httpdocs/index.php(87): Mage::run('', 'store')
#13 {main}
Next exception 'Exception' with message 'Serialization of 'Mage_Core_Model_Config_Element' is not allowed' in /var/www/vhosts/ardo-usa.com/httpdocs/app/code/community/Strategery/Logger/Model/Logger.php:26
Stack trace:
#0 /var/www/vhosts/site.com/httpdocs/app/code/community/Strategery/Logger/Model/Logger.php(0): serialize()
#1 /var/www/vhosts/site.com/httpdocs/app/code/community/Strategery/Logger/Model/Logger.php(46): Strategery_Logger_Model_Logger->log('Info', '/admin/report_s...', Array)
#2 /var/www/vhosts/site.com/httpdocs/app/code/community/Strategery/Logger/Model/Observer.php(28): Strategery_Logger_Model_Logger->info('/admin/report_s...', Array)
#3 /var/www/vhosts/site.com/httpdocs/app/code/core/Mage/Core/Model/App.php(1338): Strategery_Logger_Model_Observer->info(Object(Varien_Event_Observer))
#4 /var/www/vhosts/site.com/httpdocs/app/code/core/Mage/Core/Model/App.php(1317): Mage_Core_Model_App->_callObserverMethod(Object(Strategery_Logger_Model_Observer), 'info', Object(Varien_Event_Observer))
#5 /var/www/vhosts/ardo-usa.com/httpdocs/app/Mage.php(448): Mage_Core_Model_App->dispatchEvent('controller_acti...', Array)
#6 /var/www/vhosts/site.com/httpdocs/app/code/core/Mage/Core/Controller/Varien/Action.php(550): Mage::dispatchEvent('controller_acti...', Array)
#7 /var/www/vhosts/site.com/httpdocs/app/code/core/Mage/Core/Controller/Varien/Action.php(422): Mage_Core_Controller_Varien_Action->postDispatch()
#8 /var/www/vhosts/site.com/httpdocs/app/code/core/Mage/Core/Controller/Varien/Router/Standard.php(250): Mage_Core_Controller_Varien_Action->dispatch('coupons')
#9 /var/www/vhosts/site.com/httpdocs/app/code/core/Mage/Core/Controller/Varien/Front.php(172): Mage_Core_Controller_Varien_Router_Standard->match(Object(Mage_Core_Controller_Request_Http))
#10 /var/www/vhosts/site.com/httpdocs/app/code/core/Mage/Core/Model/App.php(354): Mage_Core_Controller_Varien_Front->dispatch()
#11 /var/www/vhosts/site.com/httpdocs/app/Mage.php(684): Mage_Core_Model_App->run(Array)
#12 /var/www/vhosts/site.com/httpdocs/index.php(87): Mage::run('', 'store')
#13 {main}
Notice that I use tail with the -n 20 flag to get it to print the last 20 lines insted of the default 10. That's because the exception.log file contains the full stack trace generated when the exception was thrown and includes every function that was called during the failure. Look for the first sentence before the lines starting with # character. That will tell you what file caused the exception and what line of code caused the error. In the above case, it was a plugin so I'd probably review what was happeneing and contact the vendor if needed.
Hope this helps troubelshoot the issue, post your findings in here (but obscure any sensitive info from your systems when you do) and I'll see if I can help further in the debug process.
