Innodb mutex locking ?!? Inserts start stacking after 18-24hours, restart required
Similar to my problem if you have the performance_schema enabled, solved after the upgrade of MySql server version.

Starting from 5.5.16 to 5.5.22 is affected by a deadlock. 
No queries can be run when it happens:
Bug 13898343 - THREAD LOOPS ENDLESSLY IN LF_PINBOX_PUT_PINS WHILE HOLDING LOCK_THREAD_COUNT

An infinite thread loop could develop within Performance Schema, 
causing the server to become unresponsive. (Bug #13898343)


See changelog

First of all try disabling performance_schema

Hope his helps