From: Guenter Roeck Date: Sat, 10 Feb 2024 19:15:56 +0000 (-0800) Subject: parisc: Fix csum_ipv6_magic on 32-bit systems X-Git-Url: http://git.maquefel.me/?a=commitdiff_plain;h=4408ba75e4ba80c91fde7e10bccccf388f5c09be;p=linux.git parisc: Fix csum_ipv6_magic on 32-bit systems Calculating the IPv6 checksum on 32-bit systems missed overflows when adding the proto+len fields into the checksum. This results in the following unit test failure. # test_csum_ipv6_magic: ASSERTION FAILED at lib/checksum_kunit.c:506 Expected ( u64)csum_result == ( u64)expected, but ( u64)csum_result == 46722 (0xb682) ( u64)expected == 46721 (0xb681) not ok 5 test_csum_ipv6_magic This is probably rarely seen in the real world because proto+len are usually small values which will rarely result in overflows when calculating the checksum. However, the unit test code uses large values for the length field, causing the test to fail. Fix the problem by adding the missing carry into the final checksum. Cc: Palmer Dabbelt Fixes: 1da177e4c3f4 ("Linux-2.6.12-rc2") Cc: stable@vger.kernel.org Signed-off-by: Guenter Roeck Tested-by: Charlie Jenkins Reviewed-by: Charlie Jenkins Signed-off-by: Helge Deller --- diff --git a/arch/parisc/include/asm/checksum.h b/arch/parisc/include/asm/checksum.h index f705e5dd10742..e619e67440db9 100644 --- a/arch/parisc/include/asm/checksum.h +++ b/arch/parisc/include/asm/checksum.h @@ -163,7 +163,8 @@ static __inline__ __sum16 csum_ipv6_magic(const struct in6_addr *saddr, " ldw,ma 4(%2), %7\n" /* 4th daddr */ " addc %6, %0, %0\n" " addc %7, %0, %0\n" -" addc %3, %0, %0\n" /* fold in proto+len, catch carry */ +" addc %3, %0, %0\n" /* fold in proto+len */ +" addc 0, %0, %0\n" /* add carry */ #endif : "=r" (sum), "=r" (saddr), "=r" (daddr), "=r" (len),