Date:   Wed, 8 Mar 2023 13:07:35 -0800
From:   Andrew Morton <akpm@...ux-foundation.org>
To:     kernel test robot <lkp@...el.com>
Cc:     Marco Elver <elver@...gle.com>, llvm@...ts.linux.dev,
        oe-kbuild-all@...ts.linux.dev, linux-kernel@...r.kernel.org,
        Linux Memory Management List <linux-mm@...ck.org>,
        Andrey Konovalov <andreyknvl@...il.com>,
        Alexander Potapenko <glider@...gle.com>
Subject: Re: ld.lld: error: undefined symbol: memcpy

On Thu, 9 Mar 2023 05:01:04 +0800 kernel test robot <lkp@...el.com> wrote:

> tree:   https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git master
> head:   63355b9884b3d1677de6bd1517cd2b8a9bf53978
> commit: 36be5cba99f6f9984a9a9f0454f95a38f4184d3e kasan: treat meminstrinsic as builtins in uninstrumented files
> date:   6 days ago
> config: powerpc-randconfig-r036-20230305 (https://download.01.org/0day-ci/archive/20230309/202303090422.ss2Hbm4f-lkp@intel.com/config)
> compiler: clang version 17.0.0 (https://github.com/llvm/llvm-project 67409911353323ca5edf2049ef0df54132fa1ca7)
> reproduce (this is a W=1 build):
>         wget https://raw.githubusercontent.com/intel/lkp-tests/master/sbin/make.cross -O ~/bin/make.cross
>         chmod +x ~/bin/make.cross
>         # install powerpc cross compiling tool for clang build
>         # apt-get install binutils-powerpc-linux-gnu
>         # https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/commit/?id=36be5cba99f6f9984a9a9f0454f95a38f4184d3e
>         git remote add linus https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git
>         git fetch --no-tags linus master
>         git checkout 36be5cba99f6f9984a9a9f0454f95a38f4184d3e
>         # save the config file
>         mkdir build_dir && cp config build_dir/.config
>         COMPILER_INSTALL_PATH=$HOME/0day COMPILER=clang make.cross W=1 O=build_dir ARCH=powerpc olddefconfig
>         COMPILER_INSTALL_PATH=$HOME/0day COMPILER=clang make.cross W=1 O=build_dir ARCH=powerpc SHELL=/bin/bash
> 
> If you fix the issue, kindly add following tag where applicable
> | Reported-by: kernel test robot <lkp@...el.com>
> | Link: https://lore.kernel.org/oe-kbuild-all/202303090422.ss2Hbm4f-lkp@intel.com/
> 
> All errors (new ones prefixed by >>):
> 
> >> ld.lld: error: undefined symbol: memcpy
>    >>> referenced by xmon.c:1896 (arch/powerpc/xmon/xmon.c:1896)
>    >>>               arch/powerpc/xmon/xmon.o:(prregs) in archive vmlinux.a
>    >>> referenced by zstd_compress.c:4814 (lib/zstd/compress/zstd_compress.c:4814)
>    >>>               lib/zstd/compress/zstd_compress.o:(ZSTD_createCDict_advanced2) in archive vmlinux.a
>    >>> referenced by zstd_compress.c:4910 (lib/zstd/compress/zstd_compress.c:4910)
>    >>>               lib/zstd/compress/zstd_compress.o:(ZSTD_initStaticCDict) in archive vmlinux.a
>    >>> referenced 5 more times
> --
> >> ld.lld: error: undefined symbol: memset
>    >>> referenced by slab_common.c:579 (mm/slab_common.c:579)
>    >>>               mm/slab_common.o:(kmem_dump_obj) in archive vmlinux.a
>    >>> referenced by kasan_test.c:558 (mm/kasan/kasan_test.c:558)
>    >>>               mm/kasan/kasan_test.o:(kmalloc_oob_in_memset) in archive vmlinux.a
>    >>> referenced by kasan_test.c:505 (mm/kasan/kasan_test.c:505)
>    >>>               mm/kasan/kasan_test.o:(kmalloc_oob_memset_2) in archive vmlinux.a
>    >>> referenced 10 more times
> 

Will this fix?

From: Alexander Potapenko <glider@...gle.com>
Subject: x86: kmsan: don't rename memintrinsics in uninstrumented files
Date: Fri, 3 Mar 2023 15:14:30 +0100

clang -fsanitize=kernel-memory already replaces calls to
memset/memcpy/memmove and their __builtin_ versions with
__msan_memset/__msan_memcpy/__msan_memmove in instrumented files, so
there is no need to override them.

In non-instrumented versions we are now required to leave memset() and
friends intact, so we cannot replace them with __msan_XXX() functions.

Link: https://lkml.kernel.org/r/20230303141433.3422671-1-glider@google.com
Signed-off-by: Alexander Potapenko <glider@...gle.com>
Suggested-by: Marco Elver <elver@...gle.com>
Reviewed-by: Marco Elver <elver@...gle.com>
Cc: Kees Cook <keescook@...omium.org>
Cc: Daniel Vetter <daniel@...ll.ch>
Cc: Geert Uytterhoeven <geert@...ux-m68k.org>
Cc: Helge Deller <deller@....de>
Cc: Tetsuo Handa <penguin-kernel@...ove.sakura.ne.jp>
Signed-off-by: Andrew Morton <akpm@...ux-foundation.org>
---


--- a/arch/x86/include/asm/string_64.h~x86-kmsan-dont-rename-memintrinsics-in-uninstrumented-files
+++ a/arch/x86/include/asm/string_64.h
@@ -15,22 +15,11 @@
 #endif
 
 #define __HAVE_ARCH_MEMCPY 1
-#if defined(__SANITIZE_MEMORY__) && defined(__NO_FORTIFY)
-#undef memcpy
-#define memcpy __msan_memcpy
-#else
 extern void *memcpy(void *to, const void *from, size_t len);
-#endif
 extern void *__memcpy(void *to, const void *from, size_t len);
 
 #define __HAVE_ARCH_MEMSET
-#if defined(__SANITIZE_MEMORY__) && defined(__NO_FORTIFY)
-extern void *__msan_memset(void *s, int c, size_t n);
-#undef memset
-#define memset __msan_memset
-#else
 void *memset(void *s, int c, size_t n);
-#endif
 void *__memset(void *s, int c, size_t n);
 
 #define __HAVE_ARCH_MEMSET16
@@ -70,13 +59,7 @@ static inline void *memset64(uint64_t *s
 }
 
 #define __HAVE_ARCH_MEMMOVE
-#if defined(__SANITIZE_MEMORY__) && defined(__NO_FORTIFY)
-#undef memmove
-void *__msan_memmove(void *dest, const void *src, size_t len);
-#define memmove __msan_memmove
-#else
 void *memmove(void *dest, const void *src, size_t count);
-#endif
 void *__memmove(void *dest, const void *src, size_t count);
 
 int memcmp(const void *cs, const void *ct, size_t count);
_

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