From 4bb06b60d982355e22647b3d12d6619419f8c1fa Mon Sep 17 00:00:00 2001 From: Vasily Gorbik Date: Wed, 8 Jul 2026 12:02:14 +0200 Subject: [PATCH] s390/checksum: Fix csum_partial() without vector facility Currently csum_partial() calls csum_copy() with copy=false and dst=NULL. On machines without the vector facility, csum_copy() falls back to cksm(dst, ...), causing the checksum to be calculated from address zero instead of the source buffer. The VX implementation already checksums data loaded from src. Make the fallback do the same by passing src to cksm(). Fixes: dcd3e1de9d17 ("s390/checksum: provide csum_partial_copy_nocheck()") Reviewed-by: Heiko Carstens Signed-off-by: Vasily Gorbik --- arch/s390/lib/csum-partial.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/arch/s390/lib/csum-partial.c b/arch/s390/lib/csum-partial.c index 458abd9bac70..9d74ceff136c 100644 --- a/arch/s390/lib/csum-partial.c +++ b/arch/s390/lib/csum-partial.c @@ -23,7 +23,7 @@ static __always_inline __wsum csum_copy(void *dst, const void *src, int len, __w if (!cpu_has_vx()) { if (copy) memcpy(dst, src, len); - return cksm(dst, len, sum); + return cksm(src, len, sum); } kernel_fpu_begin(&vxstate, KERNEL_VXR_V16V23); fpu_vlvgf(16, (__force u32)sum, 1);