1 files changed, 77 insertions, 0 deletions
diff --git a/tools/testing/selftests/bpf/progs/kfunc_implicit_args_tracing.c b/tools/testing/selftests/bpf/progs/kfunc_implicit_args_tracing.c
new file mode 100644
index 000000000000..995f8b8b5b9e
--- /dev/null
+++ b/tools/testing/selftests/bpf/progs/kfunc_implicit_args_tracing.c
@@ -0,0 +1,77 @@
+// SPDX-License-Identifier: GPL-2.0
+/* Copyright (c) 2026 Meta Platforms, Inc. and affiliates. */
+
+#include <vmlinux.h>
+#include <bpf/bpf_helpers.h>
+#include <bpf/bpf_tracing.h>
+#include <errno.h>
+
+extern int bpf_kfunc_implicit_arg(int a) __weak __ksym;
+
+char _license[] SEC("license") = "GPL";
+
+/* Shared arg checks; reports arg count and aux, returns 1 on success. */
+static __always_inline __u64
+check_implicit_args(void *ctx, __u64 *arg_cnt, __u64 *aux_arg)
+{
+	__u64 a = 0, aux = 0, z = 0;
+	__u64 result;
+	__s64 err;
+
+	*arg_cnt = bpf_get_func_arg_cnt(ctx);
+	result = *arg_cnt == 2;
+
+	err = bpf_get_func_arg(ctx, 0, &a);
+	result &= err == 0 && (int)a == 5;
+
+	err = bpf_get_func_arg(ctx, 1, &aux);
+	*aux_arg = aux;
+	result &= err == 0 && aux != 0;
+
+	err = bpf_get_func_arg(ctx, 2, &z);
+	result &= err == -EINVAL;
+
+	return result;
+}
+
+__u64 fentry_result;
+__u64 fentry_arg_cnt;
+__u64 fentry_aux_arg;
+
+SEC("fentry/bpf_kfunc_implicit_arg")
+int BPF_PROG(trace_implicit_arg_fentry)
+{
+	__u64 ret = 0;
+	__s64 err;
+
+	fentry_result = check_implicit_args(ctx, &fentry_arg_cnt, &fentry_aux_arg);
+
+	err = bpf_get_func_ret(ctx, &ret);
+	fentry_result &= err == -EOPNOTSUPP;
+
+	return 0;
+}
+
+__u64 fexit_result;
+__u64 fexit_arg_cnt;
+__u64 fexit_aux_arg;
+
+SEC("fexit/bpf_kfunc_implicit_arg")
+int BPF_PROG(trace_implicit_arg_fexit)
+{
+	__u64 ret = 0;
+	__s64 err;
+
+	fexit_result = check_implicit_args(ctx, &fexit_arg_cnt, &fexit_aux_arg);
+
+	err = bpf_get_func_ret(ctx, &ret);
+	fexit_result &= err == 0 && ret == 5;
+
+	return 0;
+}
+
+SEC("syscall")
+int trigger_implicit_arg(void *ctx)
+{
+	return bpf_kfunc_implicit_arg(5);
+}