[PATCH 22/43] kmsan: initialize the output of READ_ONCE_NOCHECK()
STALE1653d
From: Alexander Potapenko <glider@google.com>
Date: 2021-12-14 16:23:17
Also in:
linux-mm, lkml
Subsystem:
generic include/asm header files, the rest · Maintainers:
Arnd Bergmann, Linus Torvalds
Revision v1 of 11 in this series.
Revisions (11)
READ_ONCE_NOCHECK() is already used by KASAN to ignore memory accesses from e.g. stack unwinders. Define READ_ONCE_NOCHECK() for KMSAN so that it returns initialized values. This helps defeat false positives from leftover stack contents. Signed-off-by: Alexander Potapenko <glider@google.com> --- Link: https://linux-review.googlesource.com/id/I07499eb3e8e59c0ad2fd486cedc932d958b37afd --- include/asm-generic/rwonce.h | 5 +++-- 1 file changed, 3 insertions(+), 2 deletions(-)
diff --git a/include/asm-generic/rwonce.h b/include/asm-generic/rwonce.h
index 8d0a6280e9824..7cf993af8e1ea 100644
--- a/include/asm-generic/rwonce.h
+++ b/include/asm-generic/rwonce.h@@ -25,6 +25,7 @@ #include <linux/compiler_types.h> #include <linux/kasan-checks.h> #include <linux/kcsan-checks.h> +#include <linux/kmsan-checks.h> /* * Yes, this permits 64-bit accesses on 32-bit architectures. These will
@@ -69,14 +70,14 @@ unsigned long __read_once_word_nocheck(const void *addr) /* * Use READ_ONCE_NOCHECK() instead of READ_ONCE() if you need to load a - * word from memory atomically but without telling KASAN/KCSAN. This is + * word from memory atomically but without telling KASAN/KCSAN/KMSAN. This is * usually used by unwinding code when walking the stack of a running process. */ #define READ_ONCE_NOCHECK(x) \ ({ \ compiletime_assert(sizeof(x) == sizeof(unsigned long), \ "Unsupported access size for READ_ONCE_NOCHECK()."); \ - (typeof(x))__read_once_word_nocheck(&(x)); \ + kmsan_init((typeof(x))__read_once_word_nocheck(&(x))); \ }) static __no_kasan_or_inline
--
2.34.1.173.g76aa8bc2d0-goog