[RFC][PATCH 0/4] FUTEX_UNLOCK_PI wobbles

[Peter Zijlstra]

Hi,

During my last PI failing patch set it became obvious there's a number of
related fail in FUTEX_UNLOCK_PI that needed sorting before we can move on
with that stuff.

These here patches are the result of staring at that code for a wee bit.

Please have a very _very_ careful look at the last patch, it appears to not
explode when running:

  - perf bench futex lock-pi
  - selftests/futex

but given the immense amount of tricky involved with both PI and futex there is
bound to be something I've overlooked.

Do people have more/better futex-pi test cases?