tree dcb17f38144e26d904c3f17bf9085315c7fabffb
parent bf236bfc9bb07a8c414f51cc928727291f7059b6
author Christopher Ferris <cferris@google.com> 1466030990 -0700
committer Christopher Ferris <cferris@google.com> 1472162513 -0700

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