On Thu, Mar 26, 2020 at 11:31:10AM -0500, Josh Poimboeuf wrote: > On Wed, Mar 25, 2020 at 10:57:02PM -0700, Kees Cook wrote: > > > In the meantime I can still change objtool to ignore unreachable UD2s if > > > there aren't any better ideas. > > > > It'll still need the objtool change for CONFIG_UBSAN_TRAP, though based on > > the clang bug discussion, I'll probably _also_ be adding CONFIG_UBSAN_WARN > > which won't have an unreachable (and won't bloat the kernel). Testing > > still under way... it is possible that CONFIG_UBSAN_TRAP will go away > > in the future, though. If that happens, should I also remove the change > > at that time? > > I'll go ahead and make the patch and post it soon. It should be pretty > trivial. We can always revert it if CONFIG_UBSAN_TRAP goes away. Awesome, thanks very much. After digging into the WARN-style option, it seems that TRAP is unlikely to go away because it's Clang only; GCC doesn't support the "minimal runtime" option. Yay compilers. Anyway, I'll still get the WARN mode sent out. Thanks for looking at this; can you CC me on the patch? I'm trying to get more familiar with objtool so I don't have to bug you when objtool is angered by crazy stuff I do. ;) -- Kees Cook
