Re: [git pull] Please pull powerpc.git next branch

On Thu, 2014-08-14 at 16:16 +1000, Benjamin Herrenschmidt wrote:

Another interesting one in the "OMG" category is the series from Michael
adding memory barriers to spin_is_locked(). That's also the result of many
days of debugging to figure out why the semaphore code would occasionally
crash in ways that made no sense. It ended up being some creative lock
stacking that was defeated by the fact that our locks allow a load inside
the locked section to be re-ordered with the load of the lock value itself
(I'm still of two mind about whether to kill that once and for all by putting
a heavier barrier back into our lock implementation...). The fixes come with
a long explanation in the cset comments, feel free to read it if you feel
like having a headache today.

Talking of which, I should have tagged that for stable... I'll forward them
separately when you've pulled.

Michael: If I miss this while I'm away next week, can you take care of it ?

Cheers,
Ben.