tracing/filters: free filter_string in destroy_preds()

filter->filter_string is not freed when unloading a module:

 # insmod trace-events-sample.ko
 # echo "bar < 100" > /mnt/tracing/events/sample/foo_bar/filter
 # rmmod trace-events-sample.ko

[ Impact: fix memory leak when unloading module ]

Signed-off-by: Li Zefan <lizf@cn.fujitsu.com>
LKML-Reference: <4A375A30.9060802@cn.fujitsu.com>
Signed-off-by: Steven Rostedt <rostedt@goodmis.org>

1 files changed, 1 insertions, 0 deletions

diff --git a/kernel/trace/trace_events_filter.c b/kernel/trace/trace_events_filter.c
index b24ab0e6ea74..d9f01c1a042b 100644
--- a/kernel/trace/trace_events_filter.c
+++ b/kernel/trace/trace_events_filter.c
@@ -381,6 +381,7 @@ void destroy_preds(struct ftrace_event_call *call)
                         filter_free_pred(filter->preds[i]);
         }
         kfree(filter->preds);
+        kfree(filter->filter_string);
         kfree(filter);
         call->filter = NULL;
 }