RFC: mutex: hung tasks on SMP platforms with asm-generic/mutex-xchg.h

On Tue, Aug 07, 2012 at 06:33:44PM +0100, Will Deacon wrote:

What I think is happening is that B writes the -1 in __mutex_lock_common
and, after seeing a NULL owner (C may not have set that yet), drops through
to the:

	if (atomic_xchg(&lock->count, -1) == 1)
		goto done;

Sorry, should have proofread that. I meant to say:

 What I think is happening is that B writes the -1 in __mutex_lock_common
 after seeing a NULL owner (C may not have set that yet) and dropping through
 to the:
 
 	if (atomic_xchg(&lock->count, -1) == 1)
 		goto done;
 

Will