1 files changed, 23 insertions, 21 deletions

diff --git a/tools/perf/util/machine.c b/tools/perf/util/machine.c
index 9e0f60a7e7b3..24f8c978cfd4 100644
--- a/tools/perf/util/machine.c
+++ b/tools/perf/util/machine.c
@@ -14,6 +14,8 @@
 #include "unwind.h"
 #include "linux/hash.h"
 
+static void machine__remove_thread(struct machine *machine, struct thread *th);
+
 static void dsos__init(struct dsos *dsos)
 {
         INIT_LIST_HEAD(&dsos->head);
@@ -89,16 +91,6 @@ static void dsos__delete(struct dsos *dsos)
         }
 }
 
-void machine__delete_dead_threads(struct machine *machine)
-{
-        struct thread *n, *t;
-
-        list_for_each_entry_safe(t, n, &machine->dead_threads, node) {
-                list_del(&t->node);
-                thread__delete(t);
-        }
-}
-
 void machine__delete_threads(struct machine *machine)
 {
         struct rb_node *nd = rb_first(&machine->threads);
@@ -106,9 +98,8 @@ void machine__delete_threads(struct machine *machine)
         while (nd) {
                 struct thread *t = rb_entry(nd, struct thread, rb_node);
 
-                rb_erase(&t->rb_node, &machine->threads);
                 nd = rb_next(nd);
-                thread__delete(t);
+                machine__remove_thread(machine, t);
         }
 }
 
@@ -361,9 +352,13 @@ static struct thread *__machine__findnew_thread(struct machine *machine,
          * the full rbtree:
          */
         th = machine->last_match;
-        if (th && th->tid == tid) {
-                machine__update_thread_pid(machine, th, pid);
-                return th;
+        if (th != NULL) {
+                if (th->tid == tid) {
+                        machine__update_thread_pid(machine, th, pid);
+                        return th;
+                }
+
+                thread__zput(machine->last_match);
         }
 
         while (*p != NULL) {
@@ -371,7 +366,7 @@ static struct thread *__machine__findnew_thread(struct machine *machine,
                 th = rb_entry(parent, struct thread, rb_node);
 
                 if (th->tid == tid) {
-                        machine->last_match = th;
+                        machine->last_match = thread__get(th);
                         machine__update_thread_pid(machine, th, pid);
                         return th;
                 }
@@ -403,8 +398,11 @@ static struct thread *__machine__findnew_thread(struct machine *machine,
                         thread__delete(th);
                         return NULL;
                 }
-
-                machine->last_match = th;
+                /*
+                 * It is now in the rbtree, get a ref
+                 */
+                thread__get(th);
+                machine->last_match = thread__get(th);
         }
 
         return th;
@@ -1238,13 +1236,17 @@ out_problem:
 
 static void machine__remove_thread(struct machine *machine, struct thread *th)
 {
-        machine->last_match = NULL;
+        if (machine->last_match == th)
+                thread__zput(machine->last_match);
+
         rb_erase(&th->rb_node, &machine->threads);
         /*
-         * We may have references to this thread, for instance in some hist_entry
-         * instances, so just move them to a separate list.
+         * Move it first to the dead_threads list, then drop the reference,
+         * if this is the last reference, then the thread__delete destructor
+         * will be called and we will remove it from the dead_threads list.
          */
         list_add_tail(&th->node, &machine->dead_threads);
+        thread__put(th);
 }
 
 int machine__process_fork_event(struct machine *machine, union perf_event *event,