From a0393787a789646ef01ebf558871c93d20a0bcb2 Mon Sep 17 00:00:00 2001 From: "Matthieu Baerts (NGI0)" Date: Fri, 3 Oct 2025 17:24:17 +0200 Subject: [PATCH] selftests/bpf: fix implicit-function-declaration errors When trying to build the latest BPF selftests, with a debug kernel config, Pahole 1.30 and CLang 20.1.8 (and GCC 15.2), I got these errors: progs/dynptr_success.c:579:9: error: call to undeclared function 'bpf_dynptr_slice'; ISO C99 and later do not support implicit function declarations [-Wimplicit-function-declaration] 579 | data = bpf_dynptr_slice(&ptr, 0, NULL, 1); | ^ progs/dynptr_success.c:579:9: note: did you mean 'bpf_dynptr_size'? .virtme/build-debug-btf//tools/include/vmlinux.h:120280:14: note: 'bpf_dynptr_size' declared here 120280 | extern __u32 bpf_dynptr_size(const struct bpf_dynptr *p) __weak __ksym; | ^ progs/dynptr_success.c:579:7: error: incompatible integer to pointer conversion assigning to '__u64 *' (aka 'unsigned long long *') from 'int' [-Wint-conversion] 579 | data = bpf_dynptr_slice(&ptr, 0, NULL, 1); | ^ ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ progs/dynptr_success.c:596:9: error: call to undeclared function 'bpf_dynptr_slice'; ISO C99 and later do not support implicit function declarations [-Wimplicit-function-declaration] 596 | data = bpf_dynptr_slice(&ptr, 0, NULL, 10); | ^ progs/dynptr_success.c:596:7: error: incompatible integer to pointer conversion assigning to 'char *' from 'int' [-Wint-conversion] 596 | data = bpf_dynptr_slice(&ptr, 0, NULL, 10); | ^ ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ I don't have these errors without the debug kernel config from kernel/configs/debug.config. With the debug kernel, bpf_dynptr_slice() is not declared in vmlinux.h. It is declared there without debug.config. The fix is similar to what is done in dynptr_fail.c which is also using bpf_dynptr_slice(): bpf_kfuncs.h is now included. Signed-off-by: Matthieu Baerts (NGI0) --- tools/testing/selftests/bpf/progs/dynptr_success.c | 1 + 1 file changed, 1 insertion(+) diff --git a/tools/testing/selftests/bpf/progs/dynptr_success.c b/tools/testing/selftests/bpf/progs/dynptr_success.c index 127dea342e5a6..60daf5ce8eb28 100644 --- a/tools/testing/selftests/bpf/progs/dynptr_success.c +++ b/tools/testing/selftests/bpf/progs/dynptr_success.c @@ -6,6 +6,7 @@ #include #include #include +#include "bpf_kfuncs.h" #include "bpf_misc.h" #include "errno.h"