[openib-general] Kernel Oops related to IPoIB (multicast module?)

[Sean Hefty]

Jack Morgenstein wrote:
> The following Oops occurred upon unloading the openib driver.  I unloaded the
> driver immediately following a reboot (the driver had been loaded during the
> boot sequence).  I did NOT run opensm before unloading the driver.
> 
> Evidently, ipoib was still attempting to connect with an SA, when the ipoib
> module was unloaded (modprobe -r). After the ipoib module was unloaded (or at
> least rendered inaccessible), the ib_sa module attempted to invoke 
> "ib_sa_mcmember_rec_callback" (for a callback address that was part of the
> unloaded ipoib module).  Hence, the Oops below.
> 
> The "modprobe" process in the trace below is "modprobe -r ib_sa" (After
> unloading ib_ipoib, we attempt to unload ib_sa). Following the Oops, I've
> included info on the running environment.

Thanks for the additional information.  I've been trying to reproduce this, but
haven't been able to yet.  I did notice that there's a several second delay when
calling modprobe -r ip_iboib, but only if I've tried to configure ib0 first.
(No SM was running.)

I am confused on one area.  After executing modprobe -r ib_ipoib, what kept
ib_sa loaded?  (Why was modprobe -r ib_sa necessary?)  I would have expected it
to be unloaded at the same time.

- Sean