v4.19.13 snapshot.
diff --git a/tools/perf/tests/thread-mg-share.c b/tools/perf/tests/thread-mg-share.c
new file mode 100644
index 0000000..b1d1bba
--- /dev/null
+++ b/tools/perf/tests/thread-mg-share.c
@@ -0,0 +1,99 @@
+// SPDX-License-Identifier: GPL-2.0
+#include "tests.h"
+#include "machine.h"
+#include "thread.h"
+#include "map.h"
+#include "debug.h"
+
+int test__thread_mg_share(struct test *test __maybe_unused, int subtest __maybe_unused)
+{
+ struct machines machines;
+ struct machine *machine;
+
+ /* thread group */
+ struct thread *leader;
+ struct thread *t1, *t2, *t3;
+ struct map_groups *mg;
+
+ /* other process */
+ struct thread *other, *other_leader;
+ struct map_groups *other_mg;
+
+ /*
+ * This test create 2 processes abstractions (struct thread)
+ * with several threads and checks they properly share and
+ * maintain map groups info (struct map_groups).
+ *
+ * thread group (pid: 0, tids: 0, 1, 2, 3)
+ * other group (pid: 4, tids: 4, 5)
+ */
+
+ machines__init(&machines);
+ machine = &machines.host;
+
+ /* create process with 4 threads */
+ leader = machine__findnew_thread(machine, 0, 0);
+ t1 = machine__findnew_thread(machine, 0, 1);
+ t2 = machine__findnew_thread(machine, 0, 2);
+ t3 = machine__findnew_thread(machine, 0, 3);
+
+ /* and create 1 separated process, without thread leader */
+ other = machine__findnew_thread(machine, 4, 5);
+
+ TEST_ASSERT_VAL("failed to create threads",
+ leader && t1 && t2 && t3 && other);
+
+ mg = leader->mg;
+ TEST_ASSERT_EQUAL("wrong refcnt", refcount_read(&mg->refcnt), 4);
+
+ /* test the map groups pointer is shared */
+ TEST_ASSERT_VAL("map groups don't match", mg == t1->mg);
+ TEST_ASSERT_VAL("map groups don't match", mg == t2->mg);
+ TEST_ASSERT_VAL("map groups don't match", mg == t3->mg);
+
+ /*
+ * Verify the other leader was created by previous call.
+ * It should have shared map groups with no change in
+ * refcnt.
+ */
+ other_leader = machine__find_thread(machine, 4, 4);
+ TEST_ASSERT_VAL("failed to find other leader", other_leader);
+
+ /*
+ * Ok, now that all the rbtree related operations were done,
+ * lets remove all of them from there so that we can do the
+ * refcounting tests.
+ */
+ machine__remove_thread(machine, leader);
+ machine__remove_thread(machine, t1);
+ machine__remove_thread(machine, t2);
+ machine__remove_thread(machine, t3);
+ machine__remove_thread(machine, other);
+ machine__remove_thread(machine, other_leader);
+
+ other_mg = other->mg;
+ TEST_ASSERT_EQUAL("wrong refcnt", refcount_read(&other_mg->refcnt), 2);
+
+ TEST_ASSERT_VAL("map groups don't match", other_mg == other_leader->mg);
+
+ /* release thread group */
+ thread__put(leader);
+ TEST_ASSERT_EQUAL("wrong refcnt", refcount_read(&mg->refcnt), 3);
+
+ thread__put(t1);
+ TEST_ASSERT_EQUAL("wrong refcnt", refcount_read(&mg->refcnt), 2);
+
+ thread__put(t2);
+ TEST_ASSERT_EQUAL("wrong refcnt", refcount_read(&mg->refcnt), 1);
+
+ thread__put(t3);
+
+ /* release other group */
+ thread__put(other_leader);
+ TEST_ASSERT_EQUAL("wrong refcnt", refcount_read(&other_mg->refcnt), 1);
+
+ thread__put(other);
+
+ machines__exit(&machines);
+ return 0;
+}