Re: [PATCH RFC v3 28/36] kmsan: enable KMSAN builds

[Andrey Konovalov <andreyknvl@google.com>]

On Fri, Nov 22, 2019 at 12:27 PM <glider@google.com> wrote:
>
> Make KMSAN usable by adding the necessary Makefile bits and calling
> KMSAN initialization routines (kmsan_initialize_shadow() and
> kmsan_initialize()) from init/main.c

I think it makes sense to split these two parts into separate patches as well.

>
> Signed-off-by: Alexander Potapenko <glider@google.com>
> To: Alexander Potapenko <glider@google.com>
> Cc: Jens Axboe <axboe@kernel.dk>
> Cc: Andy Lutomirski <luto@kernel.org>
> Cc: Vegard Nossum <vegard.nossum@oracle.com>
> Cc: Dmitry Vyukov <dvyukov@google.com>
> Cc: linux-mm@kvack.org
>
> ---
> This patch was previously called "kmsan: Changing existing files to
> enable KMSAN builds". Logically unrelated parts of it were split away.
>
> Change-Id: I37e0b7f2d2f2b0aeac5753ff9d6b411485fc374e
> ---
>  Makefile             | 3 ++-
>  init/main.c          | 3 +++
>  mm/Makefile          | 1 +
>  scripts/Makefile.lib | 6 ++++++
>  4 files changed, 12 insertions(+), 1 deletion(-)
>
> diff --git a/Makefile b/Makefile
> index 79be70bf2899..181ae2dac415 100644
> --- a/Makefile
> +++ b/Makefile
> @@ -478,7 +478,7 @@ export KBUILD_HOSTCXXFLAGS KBUILD_HOSTLDFLAGS KBUILD_HOSTLDLIBS LDFLAGS_MODULE
>
>  export KBUILD_CPPFLAGS NOSTDINC_FLAGS LINUXINCLUDE OBJCOPYFLAGS KBUILD_LDFLAGS
>  export KBUILD_CFLAGS CFLAGS_KERNEL CFLAGS_MODULE
> -export CFLAGS_KASAN CFLAGS_KASAN_NOSANITIZE CFLAGS_UBSAN
> +export CFLAGS_KASAN CFLAGS_KASAN_NOSANITIZE CFLAGS_UBSAN CFLAGS_KMSAN
>  export KBUILD_AFLAGS AFLAGS_KERNEL AFLAGS_MODULE
>  export KBUILD_AFLAGS_MODULE KBUILD_CFLAGS_MODULE KBUILD_LDFLAGS_MODULE
>  export KBUILD_AFLAGS_KERNEL KBUILD_CFLAGS_KERNEL
> @@ -898,6 +898,7 @@ KBUILD_CFLAGS += $(call cc-option,-fcf-protection=none)
>  endif
>
>  include scripts/Makefile.kasan
> +include scripts/Makefile.kmsan
>  include scripts/Makefile.extrawarn
>  include scripts/Makefile.ubsan
>
> diff --git a/init/main.c b/init/main.c
> index 91f6ebb30ef0..afcca2a38348 100644
> --- a/init/main.c
> +++ b/init/main.c
> @@ -32,6 +32,7 @@
>  #include <linux/nmi.h>
>  #include <linux/percpu.h>
>  #include <linux/kmod.h>
> +#include <linux/kmsan.h>
>  #include <linux/vmalloc.h>
>  #include <linux/kernel_stat.h>
>  #include <linux/start_kernel.h>
> @@ -554,6 +555,7 @@ static void __init mm_init(void)
>          */
>         page_ext_init_flatmem();
>         report_meminit();
> +       kmsan_initialize_shadow();
>         mem_init();
>         kmem_cache_init();
>         kmemleak_init();
> @@ -625,6 +627,7 @@ asmlinkage __visible void __init start_kernel(void)
>         sort_main_extable();
>         trap_init();
>         mm_init();
> +       kmsan_initialize();
>
>         ftrace_init();
>
> diff --git a/mm/Makefile b/mm/Makefile
> index d996846697ef..419e6e02dfaf 100644
> --- a/mm/Makefile
> +++ b/mm/Makefile
> @@ -71,6 +71,7 @@ obj-$(CONFIG_PAGE_POISONING) += page_poison.o
>  obj-$(CONFIG_SLAB) += slab.o
>  obj-$(CONFIG_SLUB) += slub.o
>  obj-$(CONFIG_KASAN)    += kasan/
> +obj-$(CONFIG_KMSAN)    += kmsan/
>  obj-$(CONFIG_FAILSLAB) += failslab.o
>  obj-$(CONFIG_MEMORY_HOTPLUG) += memory_hotplug.o
>  obj-$(CONFIG_MEMTEST)          += memtest.o
> diff --git a/scripts/Makefile.lib b/scripts/Makefile.lib
> index 179d55af5852..f9f38f7c1cd4 100644
> --- a/scripts/Makefile.lib
> +++ b/scripts/Makefile.lib
> @@ -140,6 +140,12 @@ _c_flags += $(if $(patsubst n%,, \
>                 $(CFLAGS_KASAN), $(CFLAGS_KASAN_NOSANITIZE))
>  endif
>
> +ifeq ($(CONFIG_KMSAN),y)
> +_c_flags += $(if $(patsubst n%,, \
> +               $(KMSAN_SANITIZE_$(basetarget).o)$(KMSAN_SANITIZE)y), \
> +               $(CFLAGS_KMSAN))
> +endif
> +
>  ifeq ($(CONFIG_UBSAN),y)
>  _c_flags += $(if $(patsubst n%,, \
>                 $(UBSAN_SANITIZE_$(basetarget).o)$(UBSAN_SANITIZE)$(CONFIG_UBSAN_SANITIZE_ALL)), \
> --
> 2.24.0.432.g9d3f5f5b63-goog
>