Messages in this thread | | | Date | Tue, 16 Mar 2021 11:49:20 -0700 | From | Kees Cook <> | Subject | Re: [PATCH v8 3/8] Use atomic_t for ucounts reference counting |
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On Mon, Mar 15, 2021 at 03:19:17PM -0700, Linus Torvalds wrote: > It just saturates, and doesn't have the "don't do this" case, which > the ucounts case *DOES* have.
Right -- I saw that when digging through the thread. I'm honestly curious, though, why did the 0-day bot find a boot crash? (I can't imagine ucounts wrapped in 0.4 seconds.) So it looked like an increment-from-zero case, which seems like it would be a bug?
> I know you are attached to refcounts, but really: they are not only > more expensive, THEY LITERALLY DO THE WRONG THING.
Heh, right -- I'm not arguing that refcount_t MUST be used, I just didn't see the code path that made them unsuitable: hitting INT_MAX - 128 seems very hard to do. Anyway, I'll go study it more to try to understand what I'm missing.
-- Kees Cook
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