Hi Kees, On Thu, May 01, 2025 at 12:48:17PM -0700, Kees Cook wrote: > While the randstruct GCC plugin was being rebuilt if the randstruct > seed changed, Clangs build did not notice the change. Include the hash > header directly so that it becomes a universal build dependency and full > rebuilds will happen if it changes. > > Signed-off-by: Kees Cook <[email protected]> > --- > Cc: Masahiro Yamada <[email protected]> > Cc: Nathan Chancellor <[email protected]> > Cc: Nicolas Schier <[email protected]> > Cc: Petr Pavlu <[email protected]> > Cc: Sebastian Andrzej Siewior <[email protected]> > Cc: <[email protected]> > --- > include/linux/vermagic.h | 1 - > scripts/Makefile.randstruct | 3 ++- > scripts/basic/Makefile | 11 ++++++----- > 3 files changed, 8 insertions(+), 7 deletions(-) > > diff --git a/include/linux/vermagic.h b/include/linux/vermagic.h > index 939ceabcaf06..335c360d4f9b 100644 > --- a/include/linux/vermagic.h > +++ b/include/linux/vermagic.h > @@ -33,7 +33,6 @@ > #define MODULE_VERMAGIC_MODVERSIONS "" > #endif > #ifdef RANDSTRUCT > -#include <generated/randstruct_hash.h> > #define MODULE_RANDSTRUCT "RANDSTRUCT_" RANDSTRUCT_HASHED_SEED > #else > #define MODULE_RANDSTRUCT > diff --git a/scripts/Makefile.randstruct b/scripts/Makefile.randstruct > index 24e283e89893..ab87219c6149 100644 > --- a/scripts/Makefile.randstruct > +++ b/scripts/Makefile.randstruct > @@ -12,6 +12,7 @@ randstruct-cflags-y \ > += -frandomize-layout-seed-file=$(objtree)/scripts/basic/randstruct.seed > endif > > -export RANDSTRUCT_CFLAGS := $(randstruct-cflags-y) > +export RANDSTRUCT_CFLAGS := $(randstruct-cflags-y) \ > + -include $(objtree)/scripts/basic/randstruct_hash.h
As the kernel test robot points out (on a report that you weren't included on for some reason...), this breaks the build in several places on next-20250502. https://lore.kernel.org/[email protected]/ $ make -skj"$(nproc)" ARCH=arm LLVM=1 clean allmodconfig arch/arm/vdso/vgettimeofday.o clang: error: cannot specify -o when generating multiple output files There are places in the kernel that filter out RANDSTRUCT_CFLAGS and this appears to cause other '-include' flags to be filtered out as well, such as the one in the efistub that includes hidden.h. > KBUILD_CFLAGS += $(RANDSTRUCT_CFLAGS) > diff --git a/scripts/basic/Makefile b/scripts/basic/Makefile > index dd289a6725ac..31637ce4dc5c 100644 > --- a/scripts/basic/Makefile > +++ b/scripts/basic/Makefile > @@ -8,9 +8,10 @@ hostprogs-always-y += fixdep > # before running a Clang kernel build. > gen-randstruct-seed := $(srctree)/scripts/gen-randstruct-seed.sh > quiet_cmd_create_randstruct_seed = GENSEED $@ > -cmd_create_randstruct_seed = \ > - $(CONFIG_SHELL) $(gen-randstruct-seed) \ > - $@ $(objtree)/include/generated/randstruct_hash.h > -$(obj)/randstruct.seed: $(gen-randstruct-seed) FORCE > + cmd_create_randstruct_seed = $(CONFIG_SHELL) $(gen-randstruct-seed) \ > + $(obj)/randstruct.seed $(obj)/randstruct_hash.h > + > +$(obj)/randstruct_hash.h $(obj)/randstruct.seed: $(gen-randstruct-seed) FORCE > $(call if_changed,create_randstruct_seed) > -always-$(CONFIG_RANDSTRUCT) += randstruct.seed > + > +always-$(CONFIG_RANDSTRUCT) += randstruct.seed randstruct_hash.h > -- > 2.34.1 >
