On Mon, Aug 30, 2021 at 09:31:28PM -0700, Guenter Roeck wrote: > On Fri, Aug 27, 2021 at 09:30:14AM -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 e4f5895badb5..8e7e73a642e2 100644 > > --- a/Makefile > > +++ b/Makefile > > @@ -995,7 +995,6 @@ 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 += $(call cc-disable-warning, array-bounds) > > KBUILD_CFLAGS += $(call cc-disable-warning, stringop-overflow) > > > > This patch causes 'alpha' builds to fail when trying to build an image with > gcc 11.2. > > In file included from include/linux/string.h:20, > from include/linux/bitmap.h:11, > from include/linux/cpumask.h:12, > from include/linux/smp.h:13, > from include/linux/lockdep.h:14, > from include/linux/spinlock.h:63, > from include/linux/mmzone.h:8, > from include/linux/gfp.h:6, > from include/linux/mm.h:10, > from include/linux/pagemap.h:8, > from arch/alpha/mm/init.c:10: > 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); > > Seen in next-20210830. Ah-ha, thanks for the report! I didn't see this in my builds -- what config target did you use for this? Looks like GCC isn't happy about an unsigned long->void * conversion here... include/asm/page.h:#define PAGE_OFFSET 0xfffffc0000000000UL ... include/uapi/asm/setup.h:#define KERNEL_START_PHYS 0x1000000 /* required: Wildfire/Titan/Marvel */ include/uapi/asm/setup.h:#define EMPTY_PGT (PAGE_OFFSET+KERNEL_START_PHYS+0x04000) ... mm/init.c: memset((void *) EMPTY_PGT, 0, PAGE_SIZE); I'll try to figure out the right annotations to fix this... -- Kees Cook
