On Wed, 6 Dec 2006, Matthew Wilcox wrote: > It's just been pointed out to me that the parisc one isn't safe. > > <dhowells> imagine variable X is set to 3 > <dhowells> CPU A issues cmpxchg(&X, 3, 5) > <dhowells> you'd expect that to change X to 5 > <dhowells> but what if CPU B assigns 6 to X between cmpxchg reading X > and it setting X?
The same could happen with a regular cmpxchg. Cmpxchg changes it to 5 and then other cpu performs a store before the next instruction. - To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to [EMAIL PROTECTED] More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
