Comment 3 for bug 1342158

After a bit of searching it looks like this is a bug in file: sql/sql_show.cc function: mysqld_list_processes() . I noticed a recent commit in the upstream MySQL 5.6 code base that makes a copy of the global thread list and changes the thread lock to monitor removed threads. This insures that newly created threads aren't included in the loop and that old threads cannot be removed during processing.

It's just a hunch but it might be worth taking a quick look at:

http://bazaar.launchpad.net/~mysql/mysql-server/5.6/revision/5927#sql/sql_show.cc