[openib-general] Fwd: issues in ipoib

[Roland Dreier]

    Michael> No, I think there's no problem - user callback has
    Michael> finished running and that's all we care about.

I don't think so -- because then the unregister call can return and
the client module free the client struct before the wake_up() runs,
which leads to use-after-free.

    Michael> But I'd like to point out that using rwsem gets all these
    Michael> corners right automatically. Reconsider that approach?

Again, I don't think so -- rwsem just hides the race from you.  There
is a race with semaphores (access semaphore after waking up waiter)
which is the original reason for creating struct completion.

 - R.