[c-nsp] CEF CPUHOG on GSR 12.0(S)

[David Freedman]

Recently we've been seeing some messages in the log with regards to
a CPUHOG event occuring on some engine 2 linecards we have running.

It didn't seem to be traffic affecting, and looked a little like this:

SLOT 6:Oct 12 03:17:41 DST: %SYS-3-CPUHOG: Task ran for 7312 msec (0/0),
process = CEF LC IPC Background, PC = 400FC324.

Box is running 12.0(32)S5 and has not logged these messages before.

This slot faces an upstream provider.

Upon speaking with another provider, running 12.0(32)S6, they have
been seeing the same messages on their kit but not at the same times, on
E2 linecards facing an IXP, they are running S6.

We are both running IPv6 and I have all routing messages filtered on the
upstream port (in case this was related to any RH0 nastyness)

#sh ipv6 access-list
IPv6 access list bogons6
    deny ipv6 any any routing sequence 10
<snip>

One thing of note is that this could be related to bugid CSCsb12281 but
this does not seem to effect S6, could any friendly cisco people on here
expand a bit on this bug?

Many thanks,

Dave.