Messages in this thread | | | Date | Wed, 12 Jan 2022 12:06:04 +0100 | From | Peter Zijlstra <> | Subject | Re: [PATCH v2 1/1] psi: Fix uaf issue when psi trigger is destroyed while being polled |
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On Tue, Jan 11, 2022 at 11:11:32AM -0800, Linus Torvalds wrote:
> Of course, in practice, for pointers, the whole "dereference off a > pointer" on the read side *does* imply a barrier in all relevant > situations. So yes, a smp_store_release() -> READ_ONCE() does work in > practice, although it's technically wrong (in particular, it's wrong > on alpha, because of the completely broken memory ordering that alpha > has that doesn't even honor data dependencies as read-side orderings)
On a tangent, that actually works, even on Alpha, see commit d646285885154 ("alpha: Override READ_ONCE() with barriered implementation").
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