| From | Linus Torvalds <> | Date | Fri, 2 Sep 2022 09:43:45 -0700 | Subject | Re: [PATCH v2 37/59] x86/putuser: Provide room for padding |
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So I don't hate this patch and it's probably good for consistency, but I really think that the retbleed tracking could perhaps be improved to let this be all unnecessary.
The whole return stack depth counting is already not 100% exact, and I think we could just make the rule be that we don't track leaf functions.
Why? It's just a off-by-one in the already not exact tracking. And - perhaps equally importantly - leaf functions are very very common dynamically, and I suspect it's trivial to see them.
Yes, yes, you could make objtool even smarter and actually do some kind of function flow graph thing (and I think some people were talking about that with the whole ret counting long long ago), but the leaf function thing is the really simple low-hanging fruit case of that.
Linus
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