[PATCH 4.14 006/104] kasan: add no_sanitize attribute for clang builds

[Greg Kroah-Hartman]

4.14-stable review patch.  If anyone has any objections, please let me know.

------------------

From: Andrey Konovalov <andreyknvl@xxxxxxxxxx>

commit 12c8f25a016dff69ee284aa3338bebfd2cfcba33 upstream.

KASAN uses the __no_sanitize_address macro to disable instrumentation of
particular functions.  Right now it's defined only for GCC build, which
causes false positives when clang is used.

This patch adds a definition for clang.

Note, that clang's revision 329612 or higher is required.

[andreyknvl@xxxxxxxxxx: remove redundant #ifdef CONFIG_KASAN check]
  Link: http://lkml.kernel.org/r/c79aa31a2a2790f6131ed607c58b0dd45dd62a6c.1523967959.git.andreyknvl@xxxxxxxxxx
Link: http://lkml.kernel.org/r/4ad725cc903f8534f8c8a60f0daade5e3d674f8d.1523554166.git.andreyknvl@xxxxxxxxxx
Signed-off-by: Andrey Konovalov <andreyknvl@xxxxxxxxxx>
Acked-by: Andrey Ryabinin <aryabinin@xxxxxxxxxxxxx>
Cc: Alexander Potapenko <glider@xxxxxxxxxx>
Cc: Dmitry Vyukov <dvyukov@xxxxxxxxxx>
Cc: David Rientjes <rientjes@xxxxxxxxxx>
Cc: Thomas Gleixner <tglx@xxxxxxxxxxxxx>
Cc: Ingo Molnar <mingo@xxxxxxxxxx>
Cc: David Woodhouse <dwmw@xxxxxxxxxxxx>
Cc: Andrey Konovalov <andreyknvl@xxxxxxxxxx>
Cc: Will Deacon <will.deacon@xxxxxxx>
Cc: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>
Cc: Paul Lawrence <paullawrence@xxxxxxxxxx>
Cc: Sandipan Das <sandipan@xxxxxxxxxxxxxxxxxx>
Cc: Kees Cook <keescook@xxxxxxxxxxxx>
Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
Signed-off-by: Linus Torvalds <torvalds@xxxxxxxxxxxxxxxxxxxx>
Cc: Sodagudi Prasad <psodagud@xxxxxxxxxxxxxx>
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>

---
 include/linux/compiler-clang.h |    3 +++
 1 file changed, 3 insertions(+)

--- a/include/linux/compiler-clang.h
+++ b/include/linux/compiler-clang.h
@@ -17,6 +17,9 @@
  */
 #define __UNIQUE_ID(prefix) __PASTE(__PASTE(__UNIQUE_ID_, prefix), __COUNTER__)
 
+#undef __no_sanitize_address
+#define __no_sanitize_address __attribute__((no_sanitize("address")))
+
 /* Clang doesn't have a way to turn it off per-function, yet. */
 #ifdef __noretpoline
 #undef __noretpoline