archive mirror
 help / color / mirror / Atom feed
* [PATCH -tip v2] kasan: Emit different calls for instrumentable memintrinsics
@ 2023-02-13 20:10 Marco Elver
  0 siblings, 0 replies; only message in thread
From: Marco Elver @ 2023-02-13 20:10 UTC (permalink / raw)
  To: elver, Peter Zijlstra
  Cc: Masahiro Yamada, Nathan Chancellor, Nick Desaulniers,
	Nicolas Schier, Andrey Ryabinin, Alexander Potapenko,
	Andrey Konovalov, Dmitry Vyukov, Vincenzo Frascino, linux-kbuild,
	kasan-dev, linux-kernel, Ingo Molnar, Tony Lindgren, Ulf Hansson,
	Jakub Jelinek, linux-toolchains

Clang 15 will provide an option to prefix calls to memcpy/memset/memmove
with __asan_ in instrumented functions:

GCC will add support in future:

Use it to regain KASAN instrumentation of memcpy/memset/memmove on
architectures that require noinstr to be really free from instrumented
mem*() functions (all GENERIC_ENTRY architectures).

Fixes: 69d4c0d32186 ("entry, kasan, x86: Disallow overriding mem*() functions")
Signed-off-by: Marco Elver <>
* Use asan-kernel-mem-intrinsic-prefix=1, so that once GCC supports the
  param, it also works there (it needs the =1).

The Fixes tag is just there to show the dependency, and that people
shouldn't apply this patch without 69d4c0d32186.
 scripts/Makefile.kasan | 7 +++++++
 1 file changed, 7 insertions(+)

diff --git a/scripts/Makefile.kasan b/scripts/Makefile.kasan
index b9e94c5e7097..78336b04c077 100644
--- a/scripts/Makefile.kasan
+++ b/scripts/Makefile.kasan
@@ -38,6 +38,13 @@ endif
 CFLAGS_KASAN += $(call cc-param,asan-stack=$(stack_enable))
+# Instrument memcpy/memset/memmove calls by using instrumented __asan_mem*()
+# instead. With compilers that don't support this option, compiler-inserted
+# memintrinsics won't be checked by KASAN.
+CFLAGS_KASAN += $(call cc-param,asan-kernel-mem-intrinsic-prefix)

^ permalink raw reply related	[flat|nested] only message in thread

only message in thread, other threads:[~2023-02-13 20:10 UTC | newest]

Thread overview: (only message) (download: mbox.gz / follow: Atom feed)
-- links below jump to the message on this page --
2023-02-13 20:10 [PATCH -tip v2] kasan: Emit different calls for instrumentable memintrinsics Marco Elver

This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox;
as well as URLs for NNTP newsgroup(s).