[PATCH v4 5/7] kasan: allow kasan_check_read/write() to accept pointers to volatiles

From: Dmitry Vyukov
Date: Sat Jun 17 2017 - 05:15:56 EST


Currently kasan_check_read/write() accept 'const void*', make them
accept 'const volatile void*'. This is required for instrumentation
of atomic operations and there is just no reason to not allow that.

Signed-off-by: Dmitry Vyukov <dvyukov@xxxxxxxxxx>
Cc: Mark Rutland <mark.rutland@xxxxxxx>
Cc: Andrey Ryabinin <aryabinin@xxxxxxxxxxxxx>
Cc: Thomas Gleixner <tglx@xxxxxxxxxxxxx>
Cc: "H. Peter Anvin" <hpa@xxxxxxxxx>
Cc: Peter Zijlstra <peterz@xxxxxxxxxxxxx>
Cc: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
Cc: linux-kernel@xxxxxxxxxxxxxxx
Cc: x86@xxxxxxxxxx
Cc: linux-mm@xxxxxxxxx
Cc: kasan-dev@xxxxxxxxxxxxxxxx
---
include/linux/kasan-checks.h | 10 ++++++----
mm/kasan/kasan.c | 4 ++--
2 files changed, 8 insertions(+), 6 deletions(-)

diff --git a/include/linux/kasan-checks.h b/include/linux/kasan-checks.h
index b7f8aced7870..41960fecf783 100644
--- a/include/linux/kasan-checks.h
+++ b/include/linux/kasan-checks.h
@@ -2,11 +2,13 @@
#define _LINUX_KASAN_CHECKS_H

#ifdef CONFIG_KASAN
-void kasan_check_read(const void *p, unsigned int size);
-void kasan_check_write(const void *p, unsigned int size);
+void kasan_check_read(const volatile void *p, unsigned int size);
+void kasan_check_write(const volatile void *p, unsigned int size);
#else
-static inline void kasan_check_read(const void *p, unsigned int size) { }
-static inline void kasan_check_write(const void *p, unsigned int size) { }
+static inline void kasan_check_read(const volatile void *p, unsigned int size)
+{ }
+static inline void kasan_check_write(const volatile void *p, unsigned int size)
+{ }
#endif

#endif
diff --git a/mm/kasan/kasan.c b/mm/kasan/kasan.c
index c81549d5c833..edacd161c0e5 100644
--- a/mm/kasan/kasan.c
+++ b/mm/kasan/kasan.c
@@ -333,13 +333,13 @@ static void check_memory_region(unsigned long addr,
check_memory_region_inline(addr, size, write, ret_ip);
}

-void kasan_check_read(const void *p, unsigned int size)
+void kasan_check_read(const volatile void *p, unsigned int size)
{
check_memory_region((unsigned long)p, size, false, _RET_IP_);
}
EXPORT_SYMBOL(kasan_check_read);

-void kasan_check_write(const void *p, unsigned int size)
+void kasan_check_write(const volatile void *p, unsigned int size)
{
check_memory_region((unsigned long)p, size, true, _RET_IP_);
}
--
2.13.1.518.g3df882009-goog