From 4dc4793c9d93990d2566c31fb046db565fa0b6ed Mon Sep 17 00:00:00 2001 From: Guenter Roeck Date: Sat, 10 Feb 2024 11:15:56 -0800 Subject: [PATCH] parisc: Fix csum_ipv6_magic on 32-bit systems [ Upstream commit 4408ba75e4ba80c91fde7e10bccccf388f5c09be ] 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 Signed-off-by: Sasha Levin --- arch/parisc/include/asm/checksum.h | 3 ++- 1 file changed, 2 insertions(+), 1 deletion(-) diff --git a/arch/parisc/include/asm/checksum.h b/arch/parisc/include/asm/checksum.h index 7efcd901b965..0a0263951450 100644 --- a/arch/parisc/include/asm/checksum.h +++ b/arch/parisc/include/asm/checksum.h @@ -178,7 +178,8 @@ 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),