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/BacktraceMap.cpp b/libbacktrace/BacktraceMap.cpp
index ba86632..85f2436 100644
--- a/libbacktrace/BacktraceMap.cpp
+++ b/libbacktrace/BacktraceMap.cpp
@@ -35,8 +35,8 @@
}
void BacktraceMap::FillIn(uintptr_t addr, backtrace_map_t* map) {
- for (BacktraceMap::const_iterator it = begin();
- it != end(); ++it) {
+ ScopedBacktraceMapIteratorLock lock(this);
+ for (BacktraceMap::const_iterator it = begin(); it != end(); ++it) {
if (addr >= it->start && addr < it->end) {
*map = *it;
return;