[PATCH] futex: Detect mismatched requeue targets

[John Kacur]

Hello Darren

I took your patch from commit 84bc4af59081ee974dd80210e694ab59ebe51ce8
and I tried to git-cherry-pick it for v2.6.31.4-rt14

I had a little merge-commit to resolve. That wasn't too hard, but as the 
code is a bit different between the two versions, I would appreciate it if 
you could review the patch, and make sure that it still makes sense for 
v2.6.31.r-rt14

Thanks!
John