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> - $ptr.byte_sub(offset).cast::<$type>() > + ($field_ptr:expr, $Container:ty, $($fields:tt)*) => {{ > + let offset: usize = ::core::mem::offset_of!($Container, $($fields)*); > + let field_ptr = $field_ptr; > + let container_ptr = field_ptr.byte_sub(offset).cast::<$Container>(); > + if false { This jumped out at me. It's something that I'd like to recommend NOT doing, here or anywhere else, because: a) Anything of the form "if false" will get removed by any compiler worthy of the name, especially in kernel builds. b) It is a "magic trick", in that the code is on the face of it, unnecessary. So that's not something that you would pick as your first choice anyway. But as I see now that Miguel has also pointed out, the -O2 optimization level that we build at makes it either unreliable or broken, so it's Bad Magic. :) Anyway, I don't know where this pattern came from, but it's not a good one for kernel builds. thanks, -- John Hubbard