archive mirror
 help / color / mirror / Atom feed
* [PATCH -tip v3] kasan: Emit different calls for instrumentable memintrinsics
@ 2023-02-13 20:13 Marco Elver
  2023-02-14 10:18 ` Peter Zijlstra
  0 siblings, 1 reply; 2+ messages in thread
From: Marco Elver @ 2023-02-13 20:13 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 <>
* Resend with actual fix.

* 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..3b35a88af60d 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=1)

^ permalink raw reply related	[flat|nested] 2+ messages in thread

end of thread, other threads:[~2023-02-14 16:17 UTC | newest]

Thread overview: 2+ messages (download: mbox.gz / follow: Atom feed)
-- links below jump to the message on this page --
2023-02-13 20:13 [PATCH -tip v3] kasan: Emit different calls for instrumentable memintrinsics Marco Elver
2023-02-14 10:18 ` Peter Zijlstra

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).