nettrace: disable BPF program when necessary if btf_modules not supported

Signed-off-by: Menglong Dong <imagedong@tencent.com>

Author: menglongdong

shared/bpf_utils.c

@@ -114,20 +114,28 @@ exist:;
 	return 0;
 }
 
-int btf_get_arg_count(char *name)
+static struct btf *local_btf;
+const struct btf_type *btf_get_type(char *name)
 {
-	struct btf *local_btf = btf__load_vmlinux_btf();
 	const struct btf_type *t;
 	int id;
 
 	if (!local_btf)
-		return -ENOTSUP;
+		local_btf= btf__load_vmlinux_btf();
 
 	id = btf__find_by_name(local_btf, name);
 	if (id < 0)
-		return -ENOENT;
+		return NULL;
 
 	t = btf__type_by_id(local_btf, id);
+	return t;
+}
+
+int btf_get_arg_count(char *name)
+{
+	const struct btf_type *t;
+
+	t = btf_get_type(name);
 	if (!t)
 		return -ENOENT;
 

shared/bpf_utils.h

@@ -63,6 +63,7 @@ static inline int perf_output(int fd, perf_buffer_sample_fn fn)
 }
 
 int compat_bpf_attach_kprobe(int fd, char *name, bool ret);
+const struct btf_type *btf_get_type(char *name);
 int btf_get_arg_count(char *name);
 
 #endif

src/trace_tracing.c

@@ -101,14 +101,15 @@ static void tracing_load_rules()
 
 static void tracing_check_args()
 {
-	bool support_feat_args_ext;
+	bool support_feat_args_ext, support_btf_modules;
 	trace_t *trace;
 
 	support_feat_args_ext = tracing_support_feat_args_ext();
 	if (!support_feat_args_ext)
 		pr_warn("tracing kernel function with 6+ arguments is not"
-			"supportd by your kernel, following function is "
-			"skipped:\n");
+			"supportd by your kernel, following functions "
+			"are skipped:\n");
+
 	trace_for_each(trace) {
 		if (trace_is_invalid(trace) || !trace_is_enable(trace) ||
 		    !trace_is_func(trace))
@@ -119,6 +120,23 @@ static void tracing_check_args()
 			trace_set_invalid(trace);
 		}
 	}
+
+	support_btf_modules = kernel_has_config("DEBUG_INFO_BTF_MODULES");
+	if (!support_btf_modules)
+		pr_warn("CONFIG_DEBUG_INFO_BTF_MODULES is not supported "
+			"by your kernel, following functions are "
+			"skipped:\n");
+
+	trace_for_each(trace) {
+		if (trace_is_invalid(trace) || !trace_is_enable(trace) ||
+		    !trace_is_func(trace))
+			continue;
+
+		if (!support_btf_modules && !btf_get_type(trace->name)) {
+			pr_warn("\t%s\n", trace->name);
+			trace_set_invalid(trace);
+		}
+	}
 }
 
 static int tracing_trace_load()