compiler.h: Enforce that READ_ONCE_NOCHECK() access size is sizeof(long) (b16d8ecf) · Commits · 戴 / test

READ_ONCE_NOCHECK() unconditionally performs a sizeof(long)-sized access, so enforce that the size of the pointed-to object that we are loading from is the same size as 'long'. Reported-by:

Marco Elver <elver@google.com> Signed-off-by:

Will Deacon <will@kernel.org>

include/linux/compiler.h

+5 −2

Original line number	Diff line number	Diff line
		@@ -254,9 +254,12 @@ unsigned long __read_once_word_nocheck(const void *addr)
		*/
		#define READ_ONCE_NOCHECK(x) \
		({ \
		unsigned long __x = __read_once_word_nocheck(&(x)); \
		unsigned long __x; \
		compiletime_assert(sizeof(x) == sizeof(__x), \
		"Unsupported access size for READ_ONCE_NOCHECK()."); \
		__x = __read_once_word_nocheck(&(x)); \
		smp_read_barrier_depends(); \
		__x; \
		(typeof(x))__x; \
		})

		static __no_kasan_or_inline

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