Add a wrapper for memset() that prevents unpoisoning. This is useful
for filling memory allocator redzones.

Signed-off-by: Ilya Leoshkevich <iii@linux.ibm.com>
---
 include/linux/kmsan.h | 13 +++++++++++++
 1 file changed, 13 insertions(+)

diff --git a/include/linux/kmsan.h b/include/linux/kmsan.h
index 23de1b3d6aee..5f50885f2023 100644
--- a/include/linux/kmsan.h
+++ b/include/linux/kmsan.h
@@ -255,6 +255,14 @@ void kmsan_enable_current(void);
  */
 void kmsan_disable_current(void);
 
+/*
+ * memset_no_sanitize_memory(): memset() without KMSAN instrumentation.
+ */
+static inline void *memset_no_sanitize_memory(void *s, int c, size_t n)
+{
+	return __memset(s, c, n);
+}
+
 #else
 
 static inline void kmsan_init_shadow(void)
@@ -362,6 +370,11 @@ static inline void kmsan_disable_current(void)
 {
 }
 
+static inline void *memset_no_sanitize_memory(void *s, int c, size_t n)
+{
+	return memset(s, c, n);
+}
+
 #endif
 
 #endif /* _LINUX_KMSAN_H */
-- 
2.45.1

On Wed, Jun 19, 2024 at 5:45 PM Ilya Leoshkevich <iii@linux.ibm.com> wrote:
>
> Add a wrapper for memset() that prevents unpoisoning. This is useful
> for filling memory allocator redzones.
>
> Signed-off-by: Ilya Leoshkevich <iii@linux.ibm.com>
Reviewed-by: Alexander Potapenko <glider@google.com>

> ---
>  include/linux/kmsan.h | 13 +++++++++++++
>  1 file changed, 13 insertions(+)
>
> diff --git a/include/linux/kmsan.h b/include/linux/kmsan.h
> index 23de1b3d6aee..5f50885f2023 100644
> --- a/include/linux/kmsan.h
> +++ b/include/linux/kmsan.h
> @@ -255,6 +255,14 @@ void kmsan_enable_current(void);
>   */
>  void kmsan_disable_current(void);
>
> +/*
> + * memset_no_sanitize_memory(): memset() without KMSAN instrumentation.
> + */
Please make this a doc comment, like in the rest of the file.
(Please also fix kmsan_enable_current/kmsan_disable_current in the
respective patch)