The problem - a WLC may crash after being up for 120 days
A 5500, 2500 or WiSM2 controller may crash after running 7.0.240.0 for 120 days. (In some cases, it may be longer than 120 days.) Leading up to the crash, mbuf allocations will be seen to increase across time:
(5500-4) >show memory mbuf summary
Maximum number of Mbufs.......................... 4608
Number of Mbufs Free............................. 1000
Number of Mbufs In Use........................... 3608
This problem only affects release 7.0.240.0. It does not affect 4400 or WiSM1 controllers. As 7.0.240.0 was released on Jan. 30, 2013, controllers will start being affected by this bug around May 30, 2013.
This bug is CSCue76126.
Workaround
Perform a scheduled reload of the controller during a change window, before running out of mbufs.
Fixed software
This bug will be fixed in the 7.0 MR5 release, in 1QCY14. If a 7.0.240.0-based image with the fix for CSCue76126 is required before the 7.0 MR5 release, open a TAC case.
The bug does not affect 7.0.235.3, nor does it affect 7.2 or above.