On Fri, Oct 1, 2021 at 12:27 AM Kees Cook <keescook@xxxxxxxxxxxx> wrote: > > +ifdef CONFIG_CC_IS_GCC > +# The allocators already balk at large sizes, so silence the compiler > +# warnings for bounds checks involving those possible values. While > +# -Wno-alloc-size-larger-than would normally be used here, earlier versions > +# of gcc (<9.1) weirdly don't handle the option correctly when _other_ > +# warnings are produced (?!). Using -Walloc-size-larger-than=SIZE_MAX > +# doesn't work (as it is documented to), silently resolving to "0" prior to > +# version 9.1 (and producing an error more recently). Numeric values larger > +# than PTRDIFF_MAX also don't work prior to version 9.1, which are silently > +# ignored, continuing to default to PTRDIFF_MAX. So, left with no other > +# choice, we must perform a versioned check to disable this warning. > +# https://lore.kernel.org/lkml/20210824115859.187f272f@xxxxxxxxxxxxxxxx > +KBUILD_CFLAGS += $(call cc-ifversion, -ge, 0901, -Wno-alloc-size-larger-than) > +endif An amazing journey! Reviewed-by: Miguel Ojeda <ojeda@xxxxxxxxxx> Cheers, Miguel
