From 55a2346c7ac4bbf6ee6972394237bf31e29a1c05 Mon Sep 17 00:00:00 2001 From: Marco Elver Date: Thu, 22 Oct 2020 13:45:53 +0200 Subject: [PATCH] kcsan: Never set up watchpoints on NULL pointers Avoid setting up watchpoints on NULL pointers, as otherwise we would crash inside the KCSAN runtime (when checking for value changes) instead of the instrumented code. Because that may be confusing, skip any address less than PAGE_SIZE. Reviewed-by: Dmitry Vyukov Signed-off-by: Marco Elver Signed-off-by: Paul E. McKenney --- kernel/kcsan/encoding.h | 6 +++++- 1 file changed, 5 insertions(+), 1 deletion(-) diff --git a/kernel/kcsan/encoding.h b/kernel/kcsan/encoding.h index 1a6db2f..4f73db6 100644 --- a/kernel/kcsan/encoding.h +++ b/kernel/kcsan/encoding.h @@ -48,7 +48,11 @@ static inline bool check_encodable(unsigned long addr, size_t size) { - return size <= MAX_ENCODABLE_SIZE; + /* + * While we can encode addrs= PAGE_SIZE && size <= MAX_ENCODABLE_SIZE; } static inline long -- 2.7.4