tracing/events: fix memory leak when unloading module

When unloading a module, memory allocated by init_preds() and
trace_define_field() is not freed.

[ Impact: fix memory leak ]

Signed-off-by: Li Zefan <lizf@cn.fujitsu.com>
Acked-by: Frederic Weisbecker <fweisbec@gmail.com>
Acked-by: Steven Rostedt <rostedt@goodmis.org>
Cc: Tom Zanussi <tzanussi@gmail.com>
LKML-Reference: <4A00F6E0.3040503@cn.fujitsu.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>

1 files changed, 18 insertions, 0 deletions

diff --git a/kernel/trace/trace_events.c b/kernel/trace/trace_events.c
index f789ca540fe1..f251a150e75e 100644
--- a/kernel/trace/trace_events.c
+++ b/kernel/trace/trace_events.c
@@ -60,6 +60,22 @@ err:
 }
 EXPORT_SYMBOL_GPL(trace_define_field);
 
+#ifdef CONFIG_MODULES
+
+static void trace_destroy_fields(struct ftrace_event_call *call)
+{
+        struct ftrace_event_field *field, *next;
+
+        list_for_each_entry_safe(field, next, &call->fields, link) {
+                list_del(&field->link);
+                kfree(field->type);
+                kfree(field->name);
+                kfree(field);
+        }
+}
+
+#endif /* CONFIG_MODULES */
+
 static void ftrace_clear_events(void)
 {
         struct ftrace_event_call *call;
@@ -925,6 +941,8 @@ static void trace_module_remove_events(struct module *mod)
                                 unregister_ftrace_event(call->event);
                         debugfs_remove_recursive(call->dir);
                         list_del(&call->list);
+                        trace_destroy_fields(call);
+                        destroy_preds(call);
                 }
         }