From 931003e202880128dfeb9d836e12e8a2fff7eed8 Mon Sep 17 00:00:00 2001 From: Yuan Chen Date: Tue, 11 Mar 2025 08:51:19 +0900 Subject: [PATCH] bpf: Fix the xdp_adjust_tail sample prog issue BugLink: https://bugs.launchpad.net/bugs/2101915 [ Upstream commit 4236f114a3ffbbfd217436c08852e94cae372f57 ] During the xdp_adjust_tail test, probabilistic failure occurs and SKB package is discarded by the kernel. After checking the issues by tracking SKB package, it is identified that they were caused by checksum errors. Refer to checksum of the arch/arm64/include/asm/checksum.h for fixing. v2: Based on Alexei Starovoitov's suggestions, it is necessary to keep the code implementation consistent. Fixes: c6ffd1ff7856 (bpf: add bpf_xdp_adjust_tail sample prog) Signed-off-by: Yuan Chen Signed-off-by: Andrii Nakryiko Link: https://lore.kernel.org/bpf/20240930024115.52841-1-chenyuan_fl@163.com Signed-off-by: Sasha Levin Signed-off-by: Koichiro Den Signed-off-by: Stefan Bader --- samples/bpf/xdp_adjust_tail_kern.c | 1 + 1 file changed, 1 insertion(+) diff --git a/samples/bpf/xdp_adjust_tail_kern.c b/samples/bpf/xdp_adjust_tail_kern.c index ffdd548627f0..da67bcad1c63 100644 --- a/samples/bpf/xdp_adjust_tail_kern.c +++ b/samples/bpf/xdp_adjust_tail_kern.c @@ -57,6 +57,7 @@ static __always_inline void swap_mac(void *data, struct ethhdr *orig_eth) static __always_inline __u16 csum_fold_helper(__u32 csum) { + csum = (csum & 0xffff) + (csum >> 16); return ~((csum & 0xffff) + (csum >> 16)); }