On Wed, Feb 02, 2022 at 08:09:03AM -0800, Guenter Roeck wrote: > On Wed, Aug 18, 2021 at 01:11:17AM -0700, Kees Cook wrote: > > With the recent fixes for flexible arrays and expanded FORTIFY_SOURCE > > coverage, it is now possible to enable -Warray-bounds. Since both > > GCC and Clang include -Warray-bounds in -Wall, we just need to stop > > disabling it. > > > > Cc: Arnd Bergmann <arnd@xxxxxxxx> > > Cc: Masahiro Yamada <masahiroy@xxxxxxxxxx> > > Cc: linux-kbuild@xxxxxxxxxxxxxxx > > Co-developed-by: Gustavo A. R. Silva <gustavoars@xxxxxxxxxx> > > Signed-off-by: Gustavo A. R. Silva <gustavoars@xxxxxxxxxx> > > Signed-off-by: Kees Cook <keescook@xxxxxxxxxxxx> > > --- > > Makefile | 1 - > > 1 file changed, 1 deletion(-) > > > > diff --git a/Makefile b/Makefile > > index a4aca01a4835..af22b83cede7 100644 > > --- a/Makefile > > +++ b/Makefile > > @@ -1072,7 +1072,6 @@ KBUILD_CFLAGS += $(call cc-disable-warning, stringop-truncation) > > > > # We'll want to enable this eventually, but it's not going away for 5.7 at least > > KBUILD_CFLAGS += $(call cc-disable-warning, zero-length-bounds) > > -KBUILD_CFLAGS += -Wno-array-bounds > > KBUILD_CFLAGS += $(call cc-disable-warning, stringop-overflow) > > > > # Another good warning that we'll want to enable eventually > > alpha:defconfig: > > In function '__memset', > inlined from '__bad_pagetable' at arch/alpha/mm/init.c:79:2: > ./arch/alpha/include/asm/string.h:37:32: error: '__builtin_memset' offset [0, 8191] is out of the bounds [0, 0] [-Werror=array-bounds] > 37 | return __builtin_memset(s, c, n); > | ^~~~~~~~~~~~~~~~~~~~~~~~~ > In function '__memset', > inlined from '__bad_page' at arch/alpha/mm/init.c:86:2: > ./arch/alpha/include/asm/string.h:37:32: error: '__builtin_memset' offset [0, 8191] is out of the bounds [0, 0] [-Werror=array-bounds] > 37 | return __builtin_memset(s, c, n); > | ^~~~~~~~~~~~~~~~~~~~~~~~~ > In function '__memset', > inlined from 'paging_init' at arch/alpha/mm/init.c:256:2: > ./arch/alpha/include/asm/string.h:37:32: error: '__builtin_memset' offset [0, 8191] is out of the bounds [0, 0] [-Werror=array-bounds] > 37 | return __builtin_memset(s, c, n); Ah! With Arnd and Nathan's help, I saw: https://lore.kernel.org/all/20210912160149.2227137-3-linux@xxxxxxxxxxxx/ which is solving the same problem (just manifested through different diagnostics). The same solution works here. I'll get the patches sent... -- Kees Cook
