On Wed, Feb 10, 2021 at 02:17:57AM +0300, Andrey Rybainin wrote: > >>>> Subject: ubsan: Require GCC-8+ or Clang to use UBSAN > >>>> > >>>> Just like how we require GCC-8.2 for KASAN due to compiler bugs, require > >>>> a sane version of GCC for UBSAN. > >>>> > >>>> Specifically, before GCC-8 UBSAN doesn't respect -fwrapv and thinks > >>>> signed arithmetic is buggered. > >>> > >>> Actually removing CONFIG_UBSAN_SIGNED_OVERFLOW would give us the same > >>> effect without restricting GCC versions. > >> > >> Is that preferable? Always happy to remove code, just need some > >> justification behind it. > > > > Is Peter's patch acceptable or do you want to do something else? > > I do prefer to just remove the code, I'll send the patch shortly.
I have a specific goal of getting both signed and unsigned overflow detection working sanely, so removing this entirely from the kernel really makes working on that difficult. :) I view the primary problem as compiler-specific. I'd much rather we correctly mask against versions (or better yet, behaviors). -- Kees Cook
