From 3d042592ebd4c7e44974d556de0b727cb7db4dab Mon Sep 17 00:00:00 2001 From: Chenguang Zhao Date: Mon, 11 May 2026 09:43:43 +0800 Subject: [PATCH] ethtool: fix ethnl_bitmap32_not_zero() bit interval semantics ethnl_bitmap32_not_zero() should return true if some bit in [start, end) is set: - Fix inverted memchr_inv() sense: return true when the scan finds a non-zero byte, not when the middle words are all zero. - Return false for an empty interval (end <= start). - When end is 32-bit aligned, indices in [start, end) do not include any bits from map[end_word]; return false after earlier checks found no non-zero data. Fixes: 10b518d4e6dd ("ethtool: netlink bitset handling") Signed-off-by: Chenguang Zhao Signed-off-by: Jakub Kicinski --- net/ethtool/bitset.c | 8 ++++---- 1 file changed, 4 insertions(+), 4 deletions(-) diff --git a/net/ethtool/bitset.c b/net/ethtool/bitset.c index 8bb98d3ea3db..a3a2cc6480a0 100644 --- a/net/ethtool/bitset.c +++ b/net/ethtool/bitset.c @@ -92,7 +92,7 @@ static bool ethnl_bitmap32_not_zero(const u32 *map, unsigned int start, u32 mask; if (end <= start) - return true; + return false; if (start % 32) { mask = ethnl_upper_bits(start); @@ -105,11 +105,11 @@ static bool ethnl_bitmap32_not_zero(const u32 *map, unsigned int start, start_word++; } - if (!memchr_inv(map + start_word, '\0', - (end_word - start_word) * sizeof(u32))) + if (memchr_inv(map + start_word, '\0', + (end_word - start_word) * sizeof(u32))) return true; if (end % 32 == 0) - return true; + return false; return map[end_word] & ethnl_lower_bits(end); }