Fix race condition updating local map data.
If the underlying local map changes, it's possible for multiple
threads to try and modify the map data associated with the UnwindLocalMap
object. Add a lock when generating the local map to avoid this problem.
In addition, add a read lock whenever any caller gets the maps iterator.
Updated all iterator callers to make this lock.
Bug: 29387050
Bug: 31067025
(cherry picked from commit 3a14004c7f521cf2ca6dfea182fa7441e77c97e7)
Change-Id: Id00116f156a24b36085c0d5dfc3dde4d2ac55194
diff --git a/libbacktrace/backtrace_test.cpp b/libbacktrace/backtrace_test.cpp
index f6b2591..913e12d 100644
--- a/libbacktrace/backtrace_test.cpp
+++ b/libbacktrace/backtrace_test.cpp
@@ -896,6 +896,7 @@
std::unique_ptr<BacktraceMap> map(BacktraceMap::Create(pid));
// Basic test that verifies that the map is in the expected order.
+ ScopedBacktraceMapIteratorLock lock(map.get());
std::vector<map_test_t>::const_iterator test_it = test_maps.begin();
for (BacktraceMap::const_iterator it = map->begin(); it != map->end(); ++it) {
ASSERT_TRUE(test_it != test_maps.end());