On Thu, Dec 03, 2020 at 09:51:40AM +0100, Arnd Bergmann wrote: > On Thu, Dec 3, 2020 at 1:44 AM Kees Cook <keescook@xxxxxxxxxxxx> wrote: > > > > With UBSAN_OBJECT_SIZE disabled for GCC, only UBSAN_ALIGNMENT remained > > a noisy UBSAN option. Disable it for COMPILE_TEST so the rest of UBSAN > > can be used for full all*config builds or other large combinations. > > > > Link: https://lore.kernel.org/lkml/CAHk-=wgXW=YLxGN0QVpp-1w5GDd2pf1W-FqY15poKzoVfik2qA@xxxxxxxxxxxxxx/ > > Signed-off-by: Kees Cook <keescook@xxxxxxxxxxxx> > > Have you checked if this has a notable impact on allmodconfig compile speed > with gcc or clang? I think I've seen significant increases in build times before > with this, but I don't remember the actual magnitude. > > Making it 20% slower would probably be ok, but making it twice as slow might > be too much. For an x86_64 gcc allmodconfig before, I was seeing around 6m2s. After, I'm seeing around 6m17s, so that's about 8% longer build time. I will double-check clang... -- Kees Cook
