1 files changed, 17 insertions, 12 deletions

diff --git a/tools/perf/util/thread-stack.c b/tools/perf/util/thread-stack.c
index 03770af9e5cd..248ed3945bec 100644
--- a/tools/perf/util/thread-stack.c
+++ b/tools/perf/util/thread-stack.c
@@ -114,20 +114,25 @@ static int thread_stack__init(struct thread_stack *ts, struct thread *thread,
 static struct thread_stack *thread_stack__new(struct thread *thread,
                                               struct call_return_processor *crp)
 {
-        struct thread_stack *ts;
-
-        ts = zalloc(sizeof(struct thread_stack));
-        if (!ts)
-                return NULL;
-
-        ts->arr_sz = 1;
-
-        if (thread_stack__init(ts, thread, crp)) {
-                free(ts);
-                return NULL;
+        struct thread_stack *ts = thread->ts, *new_ts;
+        unsigned int old_sz = ts ? ts->arr_sz : 0;
+        unsigned int new_sz = 1;
+
+        if (!ts || new_sz > old_sz) {
+                new_ts = calloc(new_sz, sizeof(*ts));
+                if (!new_ts)
+                        return NULL;
+                if (ts)
+                        memcpy(new_ts, ts, old_sz * sizeof(*ts));
+                new_ts->arr_sz = new_sz;
+                zfree(&thread->ts);
+                thread->ts = new_ts;
+                ts = new_ts;
         }
 
-        thread->ts = ts;
+        if (!ts->stack &&
+            thread_stack__init(ts, thread, crp))
+                return NULL;
 
         return ts;
 }