Re: CET/IBT support and live-patches

On Tue, Nov 23, 2021 at 03:58:51PM -0500, Joe Lawrence wrote:

Yep, kpatch-build uses its own klp-relocation conversion and not kallsyms.

I'm not familiar with CET/IBT, but it sounds like if a function pointer
is not taken at build time (or maybe some other annotation), the
compiler won't generate the needed endbr landing spot in said function?

Currently it does, but then I'm having objtool scribble it on purpose.

 And that would be a problem for modules using kallsyms lookup to get to
said function.

Which is ofcourse the whole purpose of the exercise. If it's not
exported you don't get to call it via a back-door :-) This should kill a
whole heap of dodgy modules quite dead I hope.