On Wed, May 13, 2026 at 09:36:17AM +0200, Peter Zijlstra wrote: > On Tue, May 12, 2026 at 08:33:44PM -0700, Josh Poimboeuf wrote: > > Sometimes Clang arm64 code jumps to the end of the function for UB. > > No need to make that an error for checksum runs. > > I'm not sure I understand the rationale. If the compiler trips UB, we > want to be complaining about that no? > > Same as when clang just stops code-gen, also something we commonly see > when it hits UB.
Right, but I guess the question is, should we always warn about that, or should we only warn about it when doing stack validation or ORC or some other CFG-traversing thing? The checksum thing is only used when manually enabled by klp-build (never for normal kernel builds), so it would be a weird spot to report the Clang "jumping to the end of the function" UB. If we care about that for arm64 then the UB check probably belongs in a new standalone objtool command that would get used during a regular kernel build. -- Josh
