On some 32 bits architectures, including x86, GENMASK(31, 0) returns 0 instead of the expected ~0UL. This is the same on some 64 bits architectures with GENMASK_ULL(63, 0). This is due to an overflow in the shift operand, 1 << 32 for GENMASK, 1 << 64 for GENMASK_ULL. Fixes: 10ef6b0dffe404bcc54e94cb2ca1a5b18445a66b Cc: <stable@xxxxxxxxxxxxxxx> #v3.13+ Reported-by: Eric Paire <eric.paire@xxxxxx> Suggested-by: Peter Zijlstra <peterz@xxxxxxxxxxxxx> Signed-off-by: Maxime Coquelin <maxime.coquelin@xxxxxx> --- include/linux/bitops.h | 4 ++-- 1 file changed, 2 insertions(+), 2 deletions(-) diff --git a/include/linux/bitops.h b/include/linux/bitops.h index be5fd38..a49d7b7 100644 --- a/include/linux/bitops.h +++ b/include/linux/bitops.h @@ -18,8 +18,8 @@ * position @h. For example * GENMASK_ULL(39, 21) gives us the 64bit vector 0x000000ffffe00000. */ -#define GENMASK(h, l) (((U32_C(1) << ((h) - (l) + 1)) - 1) << (l)) -#define GENMASK_ULL(h, l) (((U64_C(1) << ((h) - (l) + 1)) - 1) << (l)) +#define GENMASK(h, l) ((~0UL >> (BITS_PER_LONG - (h - l + 1))) << l) +#define GENMASK_ULL(h, l) ((~0ULL >> (BITS_PER_LONG_LONG - (h - l + 1))) << l) extern unsigned int __sw_hweight8(unsigned int w); extern unsigned int __sw_hweight16(unsigned int w); -- 1.9.1 -- To unsubscribe from this list: send the line "unsubscribe stable" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html