ftrace: avoid duplicated function when writing set_graph_function

Impact: fix a bug in function filter setting

when writing function to set_graph_function, we should check whether it
has existed in set_graph_function to avoid duplicating.

Signed-off-by: Liming Wang <liming.wang@windriver.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>

1 files changed, 8 insertions, 2 deletions

diff --git a/kernel/trace/ftrace.c b/kernel/trace/ftrace.c
index eb57dc1ea097..d2b156538162 100644
--- a/kernel/trace/ftrace.c
+++ b/kernel/trace/ftrace.c
@@ -1425,7 +1425,7 @@ ftrace_set_func(unsigned long *array, int idx, char *buffer)
         struct dyn_ftrace *rec;
         struct ftrace_page *pg;
         int found = 0;
-        int i;
+        int i, j;
 
         if (ftrace_disabled)
                 return -ENODEV;
@@ -1443,7 +1443,13 @@ ftrace_set_func(unsigned long *array, int idx, char *buffer)
                         kallsyms_lookup(rec->ip, NULL, NULL, NULL, str);
                         if (strcmp(str, buffer) == 0) {
                                 found = 1;
-                                array[idx] = rec->ip;
+                                for (j = 0; j < idx; j++)
+                                        if (array[j] == rec->ip) {
+                                                found = 0;
+                                                break;
+                                        }
+                                if (found)
+                                        array[idx] = rec->ip;
                                 break;
                         }
                 }