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>

3 files changed, 34 insertions, 7 deletions

diff --git a/include/linux/ftrace_event.h b/include/linux/ftrace_event.h
index 5fff40c9ff59..662c1becf367 100644
--- a/include/linux/ftrace_event.h
+++ b/include/linux/ftrace_event.h
@@ -116,6 +116,7 @@ struct ftrace_event_call {
 #define MAX_FILTER_STR_VAL      128
 
 extern int init_preds(struct ftrace_event_call *call);
+extern void destroy_preds(struct ftrace_event_call *call);
 extern int filter_match_preds(struct ftrace_event_call *call, void *rec);
 extern int filter_current_check_discard(struct ftrace_event_call *call,
                                         void *rec,
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);
                 }
         }
 
diff --git a/kernel/trace/trace_events_filter.c b/kernel/trace/trace_events_filter.c
index f49486687ee2..ce07b8186710 100644
--- a/kernel/trace/trace_events_filter.c
+++ b/kernel/trace/trace_events_filter.c
@@ -346,6 +346,20 @@ static void filter_disable_preds(struct ftrace_event_call *call)
                 filter->preds[i]->fn = filter_pred_none;
 }
 
+void destroy_preds(struct ftrace_event_call *call)
+{
+        struct event_filter *filter = call->filter;
+        int i;
+
+        for (i = 0; i < MAX_FILTER_PRED; i++) {
+                if (filter->preds[i])
+                        filter_free_pred(filter->preds[i]);
+        }
+        kfree(filter->preds);
+        kfree(filter);
+        call->filter = NULL;
+}
+
 int init_preds(struct ftrace_event_call *call)
 {
         struct event_filter *filter;
@@ -374,13 +388,7 @@ int init_preds(struct ftrace_event_call *call)
         return 0;
 
 oom:
-        for (i = 0; i < MAX_FILTER_PRED; i++) {
-                if (filter->preds[i])
-                        filter_free_pred(filter->preds[i]);
-        }
-        kfree(filter->preds);
-        kfree(call->filter);
-        call->filter = NULL;
+        destroy_preds(call);
 
         return -ENOMEM;
 }