1 files changed, 24 insertions, 15 deletions

diff --git a/kernel/trace/trace_fprobe.c b/kernel/trace/trace_fprobe.c
index e27305d31fc5..b40fa59159ac 100644
--- a/kernel/trace/trace_fprobe.c
+++ b/kernel/trace/trace_fprobe.c
@@ -919,14 +919,15 @@ static void __find_tracepoint_module_cb(struct tracepoint *tp, struct module *mo
 	struct __find_tracepoint_cb_data *data = priv;
 
 	if (!data->tpoint && !strcmp(data->tp_name, tp->name)) {
-		data->tpoint = tp;
-		if (!data->mod) {
+		/* If module is not specified, try getting module refcount. */
+		if (!data->mod && mod) {
+			/* If failed to get refcount, ignore this tracepoint. */
+			if (!try_module_get(mod))
+				return;
+
 			data->mod = mod;
-			if (!try_module_get(data->mod)) {
-				data->tpoint = NULL;
-				data->mod = NULL;
-			}
 		}
+		data->tpoint = tp;
 	}
 }
 
@@ -939,11 +940,9 @@ static void __find_tracepoint_cb(struct tracepoint *tp, void *priv)
 }
 
 /*
- * Find a tracepoint from kernel and module. If the tracepoint is in a module,
- * this increments the module refcount to prevent unloading until the
- * trace_fprobe is registered to the list. After registering the trace_fprobe
- * on the trace_fprobe list, the module refcount is decremented because
- * tracepoint_probe_module_cb will handle it.
+ * Find a tracepoint from kernel and module. If the tracepoint is on the module,
+ * the module's refcount is incremented and returned as *@tp_mod. Thus, if it is
+ * not NULL, caller must call module_put(*tp_mod) after used the tracepoint.
  */
 static struct tracepoint *find_tracepoint(const char *tp_name,
 					  struct module **tp_mod)
@@ -973,6 +972,10 @@ static void reenable_trace_fprobe(struct trace_fprobe *tf)
 	}
 }
 
+/*
+ * Find a tracepoint from specified module. In this case, this does not get the
+ * module's refcount. The caller must ensure the module is not freed.
+ */
 static struct tracepoint *find_tracepoint_in_module(struct module *mod,
 						    const char *tp_name)
 {
@@ -1008,10 +1011,13 @@ static int __tracepoint_probe_module_cb(struct notifier_block *self,
 					reenable_trace_fprobe(tf);
 			}
 		} else if (val == MODULE_STATE_GOING && tp_mod->mod == tf->mod) {
-			tracepoint_probe_unregister(tf->tpoint,
+			unregister_fprobe(&tf->fp);
+			if (trace_fprobe_is_tracepoint(tf)) {
+				tracepoint_probe_unregister(tf->tpoint,
 					tf->tpoint->probestub, NULL);
-			tf->tpoint = NULL;
-			tf->mod = NULL;
+				tf->tpoint = TRACEPOINT_STUB;
+				tf->mod = NULL;
+			}
 		}
 	}
 	mutex_unlock(&event_mutex);
@@ -1201,8 +1207,11 @@ static int trace_fprobe_create_internal(int argc, const char *argv[],
 		argc = new_argc;
 		argv = new_argv;
 	}
-	if (argc > MAX_TRACE_ARGS)
+	if (argc > MAX_TRACE_ARGS) {
+		trace_probe_log_set_index(2);
+		trace_probe_log_err(0, TOO_MANY_ARGS);
 		return -E2BIG;
+	}
 
 	ret = traceprobe_expand_dentry_args(argc, argv, &dbuf);
 	if (ret)