PHP defunct

[nowhere]

Hi,
I've found that my server has a lot of entries like this:

userftp  8420  0.0  0.3 257204 63652 ?        S    14:55   0:00  |   \_ /usr/bin/php /home/userftp/public_html/wp-content/plugins/tweet-blender/ws.php
nobody    5732  0.0  0.4 265364 70860 ?        S    14:48   0:00  \_ /usr/local/apache/bin/httpd -k start -DSSL
userftp  5842  0.0  0.3 257204 63656 ?        S    14:48   0:00  |   \_ /usr/bin/php /home/userftp/public_html/wp-content/plugins/tweet-blender/ws.php
nobody    5778  0.0  0.2 226160 48724 ?        S    14:48   0:00  \_ /usr/local/apache/bin/httpd -k start -DSSL
userftp  5841  0.0  0.3 257204 63652 ?        S    14:48   0:00  |   \_ /usr/bin/php /home/userftp/public_html/wp-content/plugins/tweet-blender/ws.php
userftp 10282  0.5  0.3 257208 63656 ?        S    15:03   0:00  |   \_ /usr/bin/php /home/userftp/public_html/index.php
nobody    5820  0.0  0.3 230992 53572 ?        S    14:48   0:00  \_ /usr/local/apache/bin/httpd -k start -DSSL
nobody    5851  0.0  0.3 228560 51132 ?        S    14:48   0:00  \_ /usr/local/apache/bin/httpd -k start -DSSL
userftp  8669  0.1  0.3 257204 63648 ?        S    14:57   0:00  |   \_ /usr/bin/php /home/userftp/public_html/wp-content/plugins/tweet-blender/ws.php
nobody    5948  0.0  0.3 231032 53636 ?        S    14:49   0:00  \_ /usr/local/apache/bin/httpd -k start -DSSL
userftp  9044  0.1  0.3 257204 63652 ?        S    14:59   0:00  |   \_ /usr/bin/php /home/userftp/public_html/wp-content/plugins/tweet-blender/ws.php
nobody    5949  0.0  0.3 230992 53616 ?        S    14:49   0:00  \_ /usr/local/apache/bin/httpd -k start -DSSL
userftp  9879  0.1  0.3 257204 63652 ?        S    15:00   0:00  |   \_ /usr/bin/php /home/userftp/public_html/wp-content/plugins/tweet-blender/ws.php
nobody    5950  0.0  0.2 226156 48696 ?        S    14:49   0:00  \_ /usr/local/apache/bin/httpd -k start -DSSL
userftp  5986  0.0  0.3 257204 63656 ?        S    14:49   0:00  |   \_ /usr/bin/php /home/userftp/public_html/wp-content/plugins/tweet-blender/ws.php
userftp 10382  0.7  0.3 257208 63652 ?        S    15:04   0:00  |   \_ /usr/bin/php /home/userftp/public_html/index.php
nobody    5961  0.0  0.3 230868 53548 ?        S    14:49   0:00  \_ /usr/local/apache/bin/httpd -k start -DSSL
userftp  8697  8.4  0.0      0     0 ?        Z    14:57   0:36  |   \_ [php] <defunct>

If i do a "top" I get:

[email protected] [/dev]# top
top - 15:08:36 up 25 min,  1 user,  load average: 2.20, 3.32, 3.00
Tasks: 461 total,   2 running, 432 sleeping,   0 stopped,  27 zombie
Cpu(s): 31.1%us,  0.8%sy,  0.0%ni, 64.8%id,  3.3%wa,  0.0%hi,  0.0%si,  0.0%st
Mem:  16316232k total, 10749956k used,  5566276k free,   115964k buffers
Swap: 16383992k total,        0k used, 16383992k free,  1326548k cached

  PID USER      PR  NI  VIRT  RES  SHR S %CPU %MEM    TIME+  COMMAND
11795 userftp  20   0  261m  72m  10m R 99.6  0.5   0:12.53 php
12061 userftp  20   0  251m  62m  10m S  9.2  0.4   0:00.50 php
12060 userftp  20   0  251m  62m  10m S  8.6  0.4   0:00.50 php
12059 userftp  20   0  251m  62m  10m S  6.6  0.4   0:00.50 php
 2763 mysql     20   0 2175m  94m 4940 S  2.0  0.6   0:39.98 mysqld
12039 root      20   0 15296 1556  952 R  0.7  0.0   0:00.05 top
.....

It looks clear that /home/userftp/public_html/wp-content/plugins/tweet-blender/ws.php is the cause of this problem.
In fact the wordpress plugin error log reports:

[email protected] [/]# tail /home/userftp/public_html/wp-content/plugins/tweet-blender/error_log
[20-Aug-2013 13:10:59 UTC] PHP Warning:  Division by zero in /home/userftp/public_html/wp-content/plugins/tweet-blender/ws.php on line 151
[20-Aug-2013 13:11:15 UTC] PHP Warning:  Division by zero in /home/userftp/public_html/wp-content/plugins/tweet-blender/ws.php on line 151
[20-Aug-2013 13:11:49 UTC] PHP Warning:  Division by zero in /home/userftp/public_html/wp-content/plugins/tweet-blender/ws.php on line 151
[20-Aug-2013 13:11:50 UTC] PHP Warning:  Division by zero in /home/userftp/public_html/wp-content/plugins/tweet-blender/ws.php on line 151
[20-Aug-2013 13:12:06 UTC] PHP Warning:  Division by zero in /home/userftp/public_html/wp-content/plugins/tweet-blender/ws.php on line 151
[20-Aug-2013 13:12:41 UTC] PHP Warning:  Division by zero in /home/userftp/public_html/wp-content/plugins/tweet-blender/ws.php on line 151
[20-Aug-2013 13:12:57 UTC] PHP Warning:  Division by zero in /home/userftp/public_html/wp-content/plugins/tweet-blender/ws.php on line 151

At this point what should I do as this situation (plugin error and consequent "php defunct" zombies) is randomly causing server slowness and connection error to other websites hosted on this machine.
Of course I can contact user and tell him to disable plugin (WordPress › Tweet Blender « WordPress Plugins) but this is a patch not a solution. What would I do if all user tomorrow install that plugin?

Any suggestion is welcome
Thanks

 

[kdean]

At minimum have them make sure Tweet Blender is up-to-date, so them running an older version could be a problem.

 

[nowhere]

Already checked that and it's the last version 4.0.1
Actually in accordance with customer I've disabled it and after Apache restart things seams ok.
The major issue actually is that a single wordpress plugin can make all other hostings unreachable. I thought users were more isolated and was hard for a user to slowdown the rest of the server

 

[ThinIce]

That does come as a bit of a shock to most, but under suphp there isn't inherantly an ability to say "user n can only have x instantiations running at once".

You'll want something like CloudLinux for that, afaik

 

[cPanelMichael]

Hello

Yes, typically you will want to advise the end-user to disable that plugin or utilize software such as Cloud Linux that can limit resource usage on a per-account basis.

Thank you.

 

[nowhere]

Ok I understand.
Maybe I could just try to block specific files (like wp-cron.php or /tweet-blender/ws.php) globally on apache so users can still use cronjob to schedule them.
What could be the best way?