Does your Syslog contain KERNEL messages from various APs that look like this:
Mar 26 18:51 ip-addr1 KERNEL(ap-name-A@ip-addr1): OS_CANCEL_TIMER failed!!
Mar 26 19:05 ip-addr2 KERNEL(ap-name-B@ip-addr2): OS_CANCEL_TIMER failed!!
Mar 26 22:15 ip-addr3 KERNEL(ap-name-C@ip-addr3): OS_CANCEL_TIMER failed!!
Mar 26 22:19 ip-addr4 KERNEL(ap-name-D@ip-addr4): OS_CANCEL_TIMER failed!!
Mar 26 22:16 ip-addr5 KERNEL(ap-name-A@ip-addr5): OS_CANCEL_TIMER failed!!
Mar 26 23:51 ip-addr6 KERNEL(ap-name-F@ip-addr6): OS_CANCEL_TIMER failed!!
I am using 6.4.2.4 but you can find references to this error on AirHeads for
previous versions of ArubaOS. The error is reported by several different
models of APs. I opened a support call on this message and here is my
interpretation of the answer I got:
This has been classified as indicating a minor bug caused by a null pointer
address. The AP uses a timer as part of its logic when managing data that
is buffered for delivery to a client. When a client leaves an AP, the AP
cancels the timer that was being used for that client. Part of this
cancellation routine involves freeing up the data buffer. This would
be done by reference to a pointer. If the pointer has already been freed
or otherwise zeroed out, an error ensues. This manifests itself as a
failure in the routine for cancelling the client's timer.
I can't say with certainty but this would seem to be a benign bug and the
only way you might know about it is if you are checking your Syslog on
a daily basis. The memory allocated to the client is being "double-freed",
the NULL pointer reference is trapped (good programming practice) and
an error is reported.
If I have interpreted this incorrectly I will rely on the Aruba reviewers
to correct me.