Re: RFC: mutex: hung tasks on SMP platforms withasm-generic/mutex-xchg.h

From: Will Deacon
Date: Tue Aug 07 2012 - 13:38:17 EST


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
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