From edb799035dd7d41c3e81e1bef83e2a2120b08abb Mon Sep 17 00:00:00 2001 From: "Jose E. Marchesi" Date: Tue, 23 Jan 2024 21:17:29 +0100 Subject: bpf: avoid VLAs in progs/test_xdp_dynptr.c VLAs are not supported by either the BPF port of clang nor GCC. The selftest test_xdp_dynptr.c contains the following code: const size_t tcphdr_sz = sizeof(struct tcphdr); const size_t udphdr_sz = sizeof(struct udphdr); const size_t ethhdr_sz = sizeof(struct ethhdr); const size_t iphdr_sz = sizeof(struct iphdr); const size_t ipv6hdr_sz = sizeof(struct ipv6hdr); [...] static __always_inline int handle_ipv4(struct xdp_md *xdp, struct bpf_dynptr *xdp_ptr) { __u8 eth_buffer[ethhdr_sz + iphdr_sz + ethhdr_sz]; __u8 iph_buffer_tcp[iphdr_sz + tcphdr_sz]; __u8 iph_buffer_udp[iphdr_sz + udphdr_sz]; [...] } The eth_buffer, iph_buffer_tcp and other automatics are fixed size only if the compiler optimizes away the constant global variables. clang does this, but GCC does not, turning these automatics into variable length arrays. This patch removes the global variables and turns these values into preprocessor constants. This makes the selftest to build properly with GCC. Tested in bpf-next master. No regressions. Signed-off-by: Jose E. Marchesi Cc: Yonghong Song Cc: Eduard Zingerman Cc: david.faust@oracle.com Cc: cupertino.miranda@oracle.com Acked-by: Yonghong Song Link: https://lore.kernel.org/r/20240123201729.16173-1-jose.marchesi@oracle.com Signed-off-by: Alexei Starovoitov --- tools/testing/selftests/bpf/progs/test_xdp_dynptr.c | 10 +++++----- 1 file changed, 5 insertions(+), 5 deletions(-) (limited to 'tools') diff --git a/tools/testing/selftests/bpf/progs/test_xdp_dynptr.c b/tools/testing/selftests/bpf/progs/test_xdp_dynptr.c index 78c368e71797..67a77944ef29 100644 --- a/tools/testing/selftests/bpf/progs/test_xdp_dynptr.c +++ b/tools/testing/selftests/bpf/progs/test_xdp_dynptr.c @@ -18,11 +18,11 @@ #include "test_iptunnel_common.h" #include "bpf_kfuncs.h" -const size_t tcphdr_sz = sizeof(struct tcphdr); -const size_t udphdr_sz = sizeof(struct udphdr); -const size_t ethhdr_sz = sizeof(struct ethhdr); -const size_t iphdr_sz = sizeof(struct iphdr); -const size_t ipv6hdr_sz = sizeof(struct ipv6hdr); +#define tcphdr_sz sizeof(struct tcphdr) +#define udphdr_sz sizeof(struct udphdr) +#define ethhdr_sz sizeof(struct ethhdr) +#define iphdr_sz sizeof(struct iphdr) +#define ipv6hdr_sz sizeof(struct ipv6hdr) struct { __uint(type, BPF_MAP_TYPE_PERCPU_ARRAY); -- cgit v1.2.3