diff --git a/libunwindstack/Android.bp b/libunwindstack/Android.bp
index da18af6..8d2299f 100644
--- a/libunwindstack/Android.bp
+++ b/libunwindstack/Android.bp
@@ -183,6 +183,7 @@
         "tests/ElfTestUtils.cpp",
         "tests/IsolatedSettings.cpp",
         "tests/JitDebugTest.cpp",
+        "tests/LocalUpdatableMapsTest.cpp",
         "tests/LogFake.cpp",
         "tests/MapInfoCreateMemoryTest.cpp",
         "tests/MapInfoGetBuildIDTest.cpp",
diff --git a/libunwindstack/Maps.cpp b/libunwindstack/Maps.cpp
index 5da73e4..250e600 100644
--- a/libunwindstack/Maps.cpp
+++ b/libunwindstack/Maps.cpp
@@ -149,9 +149,10 @@
       }
 
       // Never delete these maps, they may be in use. The assumption is
-      // that there will only every be a handfull of these so waiting
+      // that there will only every be a handful of these so waiting
       // to destroy them is not too expensive.
       saved_maps_.emplace_back(std::move(info));
+      search_map_idx = old_map_idx + 1;
       maps_[old_map_idx] = nullptr;
       total_entries--;
     }
diff --git a/libunwindstack/include/unwindstack/Maps.h b/libunwindstack/include/unwindstack/Maps.h
index 1784394..e53f367 100644
--- a/libunwindstack/include/unwindstack/Maps.h
+++ b/libunwindstack/include/unwindstack/Maps.h
@@ -105,7 +105,7 @@
 
   const std::string GetMapsFile() const override;
 
- private:
+ protected:
   std::vector<std::unique_ptr<MapInfo>> saved_maps_;
 };
 
diff --git a/libunwindstack/tests/LocalUpdatableMapsTest.cpp b/libunwindstack/tests/LocalUpdatableMapsTest.cpp
new file mode 100644
index 0000000..b816b9a
--- /dev/null
+++ b/libunwindstack/tests/LocalUpdatableMapsTest.cpp
@@ -0,0 +1,274 @@
+/*
+ * Copyright (C) 2019 The Android Open Source Project
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+#include <stdint.h>
+#include <sys/mman.h>
+
+#include <string>
+#include <vector>
+
+#include <gtest/gtest.h>
+
+#include <android-base/file.h>
+#include <unwindstack/Maps.h>
+
+namespace unwindstack {
+
+class TestUpdatableMaps : public LocalUpdatableMaps {
+ public:
+  TestUpdatableMaps() : LocalUpdatableMaps() {}
+  virtual ~TestUpdatableMaps() = default;
+
+  const std::string GetMapsFile() const override { return maps_file_; }
+
+  void TestSetMapsFile(const std::string& maps_file) { maps_file_ = maps_file; }
+
+  const std::vector<std::unique_ptr<MapInfo>>& TestGetSavedMaps() { return saved_maps_; }
+
+ private:
+  std::string maps_file_;
+};
+
+class LocalUpdatableMapsTest : public ::testing::Test {
+ protected:
+  static const std::string GetDefaultMapString() {
+    return "3000-4000 r-xp 00000 00:00 0\n8000-9000 r-xp 00000 00:00 0\n";
+  }
+
+  void SetUp() override {
+    TemporaryFile tf;
+    ASSERT_TRUE(android::base::WriteStringToFile(GetDefaultMapString(), tf.path));
+
+    maps_.TestSetMapsFile(tf.path);
+    ASSERT_TRUE(maps_.Parse());
+    ASSERT_EQ(2U, maps_.Total());
+
+    MapInfo* map_info = maps_.Get(0);
+    ASSERT_TRUE(map_info != nullptr);
+    EXPECT_EQ(0x3000U, map_info->start);
+    EXPECT_EQ(0x4000U, map_info->end);
+    EXPECT_EQ(0U, map_info->offset);
+    EXPECT_EQ(PROT_READ | PROT_EXEC, map_info->flags);
+    EXPECT_TRUE(map_info->name.empty());
+
+    map_info = maps_.Get(1);
+    ASSERT_TRUE(map_info != nullptr);
+    EXPECT_EQ(0x8000U, map_info->start);
+    EXPECT_EQ(0x9000U, map_info->end);
+    EXPECT_EQ(0U, map_info->offset);
+    EXPECT_EQ(PROT_READ | PROT_EXEC, map_info->flags);
+    EXPECT_TRUE(map_info->name.empty());
+  }
+
+  TestUpdatableMaps maps_;
+};
+
+TEST_F(LocalUpdatableMapsTest, same_map) {
+  TemporaryFile tf;
+  ASSERT_TRUE(android::base::WriteStringToFile(GetDefaultMapString(), tf.path));
+
+  maps_.TestSetMapsFile(tf.path);
+  ASSERT_TRUE(maps_.Reparse());
+  ASSERT_EQ(2U, maps_.Total());
+  EXPECT_EQ(0U, maps_.TestGetSavedMaps().size());
+
+  MapInfo* map_info = maps_.Get(0);
+  ASSERT_TRUE(map_info != nullptr);
+  EXPECT_EQ(0x3000U, map_info->start);
+  EXPECT_EQ(0x4000U, map_info->end);
+  EXPECT_EQ(0U, map_info->offset);
+  EXPECT_EQ(PROT_READ | PROT_EXEC, map_info->flags);
+  EXPECT_TRUE(map_info->name.empty());
+
+  map_info = maps_.Get(1);
+  ASSERT_TRUE(map_info != nullptr);
+  EXPECT_EQ(0x8000U, map_info->start);
+  EXPECT_EQ(0x9000U, map_info->end);
+  EXPECT_EQ(0U, map_info->offset);
+  EXPECT_EQ(PROT_READ | PROT_EXEC, map_info->flags);
+  EXPECT_TRUE(map_info->name.empty());
+}
+
+TEST_F(LocalUpdatableMapsTest, same_map_new_perms) {
+  TemporaryFile tf;
+  ASSERT_TRUE(
+      android::base::WriteStringToFile("3000-4000 rwxp 00000 00:00 0\n"
+                                       "8000-9000 r-xp 00000 00:00 0\n",
+                                       tf.path));
+
+  maps_.TestSetMapsFile(tf.path);
+  ASSERT_TRUE(maps_.Reparse());
+  ASSERT_EQ(2U, maps_.Total());
+
+  MapInfo* map_info = maps_.Get(0);
+  ASSERT_TRUE(map_info != nullptr);
+  EXPECT_EQ(0x3000U, map_info->start);
+  EXPECT_EQ(0x4000U, map_info->end);
+  EXPECT_EQ(0U, map_info->offset);
+  EXPECT_EQ(PROT_READ | PROT_WRITE | PROT_EXEC, map_info->flags);
+  EXPECT_TRUE(map_info->name.empty());
+
+  map_info = maps_.Get(1);
+  ASSERT_TRUE(map_info != nullptr);
+  EXPECT_EQ(0x8000U, map_info->start);
+  EXPECT_EQ(0x9000U, map_info->end);
+  EXPECT_EQ(0U, map_info->offset);
+  EXPECT_EQ(PROT_READ | PROT_EXEC, map_info->flags);
+  EXPECT_TRUE(map_info->name.empty());
+
+  auto& saved_maps = maps_.TestGetSavedMaps();
+  ASSERT_EQ(1U, saved_maps.size());
+  map_info = saved_maps[0].get();
+  ASSERT_TRUE(map_info != nullptr);
+  EXPECT_EQ(0x3000U, map_info->start);
+  EXPECT_EQ(0x4000U, map_info->end);
+  EXPECT_EQ(0U, map_info->offset);
+  EXPECT_EQ(PROT_READ | PROT_EXEC, map_info->flags);
+  EXPECT_TRUE(map_info->name.empty());
+}
+
+TEST_F(LocalUpdatableMapsTest, same_map_new_name) {
+  TemporaryFile tf;
+  ASSERT_TRUE(
+      android::base::WriteStringToFile("3000-4000 r-xp 00000 00:00 0 /fake/lib.so\n"
+                                       "8000-9000 r-xp 00000 00:00 0\n",
+                                       tf.path));
+
+  maps_.TestSetMapsFile(tf.path);
+  ASSERT_TRUE(maps_.Reparse());
+  ASSERT_EQ(2U, maps_.Total());
+
+  MapInfo* map_info = maps_.Get(0);
+  ASSERT_TRUE(map_info != nullptr);
+  EXPECT_EQ(0x3000U, map_info->start);
+  EXPECT_EQ(0x4000U, map_info->end);
+  EXPECT_EQ(0U, map_info->offset);
+  EXPECT_EQ(PROT_READ | PROT_EXEC, map_info->flags);
+  EXPECT_EQ("/fake/lib.so", map_info->name);
+
+  map_info = maps_.Get(1);
+  ASSERT_TRUE(map_info != nullptr);
+  EXPECT_EQ(0x8000U, map_info->start);
+  EXPECT_EQ(0x9000U, map_info->end);
+  EXPECT_EQ(0U, map_info->offset);
+  EXPECT_EQ(PROT_READ | PROT_EXEC, map_info->flags);
+  EXPECT_TRUE(map_info->name.empty());
+
+  auto& saved_maps = maps_.TestGetSavedMaps();
+  ASSERT_EQ(1U, saved_maps.size());
+  map_info = saved_maps[0].get();
+  ASSERT_TRUE(map_info != nullptr);
+  EXPECT_EQ(0x3000U, map_info->start);
+  EXPECT_EQ(0x4000U, map_info->end);
+  EXPECT_EQ(0U, map_info->offset);
+  EXPECT_EQ(PROT_READ | PROT_EXEC, map_info->flags);
+  EXPECT_TRUE(map_info->name.empty());
+}
+
+TEST_F(LocalUpdatableMapsTest, only_add_maps) {
+  TemporaryFile tf;
+  ASSERT_TRUE(
+      android::base::WriteStringToFile("1000-2000 r-xp 00000 00:00 0\n"
+                                       "3000-4000 r-xp 00000 00:00 0\n"
+                                       "8000-9000 r-xp 00000 00:00 0\n"
+                                       "a000-f000 r-xp 00000 00:00 0\n",
+                                       tf.path));
+
+  maps_.TestSetMapsFile(tf.path);
+  ASSERT_TRUE(maps_.Reparse());
+  ASSERT_EQ(4U, maps_.Total());
+  EXPECT_EQ(0U, maps_.TestGetSavedMaps().size());
+
+  MapInfo* map_info = maps_.Get(0);
+  ASSERT_TRUE(map_info != nullptr);
+  EXPECT_EQ(0x1000U, map_info->start);
+  EXPECT_EQ(0x2000U, map_info->end);
+  EXPECT_EQ(0U, map_info->offset);
+  EXPECT_EQ(PROT_READ | PROT_EXEC, map_info->flags);
+  EXPECT_TRUE(map_info->name.empty());
+
+  map_info = maps_.Get(1);
+  ASSERT_TRUE(map_info != nullptr);
+  EXPECT_EQ(0x3000U, map_info->start);
+  EXPECT_EQ(0x4000U, map_info->end);
+  EXPECT_EQ(0U, map_info->offset);
+  EXPECT_EQ(PROT_READ | PROT_EXEC, map_info->flags);
+  EXPECT_TRUE(map_info->name.empty());
+
+  map_info = maps_.Get(2);
+  ASSERT_TRUE(map_info != nullptr);
+  EXPECT_EQ(0x8000U, map_info->start);
+  EXPECT_EQ(0x9000U, map_info->end);
+  EXPECT_EQ(0U, map_info->offset);
+  EXPECT_EQ(PROT_READ | PROT_EXEC, map_info->flags);
+  EXPECT_TRUE(map_info->name.empty());
+
+  map_info = maps_.Get(3);
+  ASSERT_TRUE(map_info != nullptr);
+  EXPECT_EQ(0xa000U, map_info->start);
+  EXPECT_EQ(0xf000U, map_info->end);
+  EXPECT_EQ(0U, map_info->offset);
+  EXPECT_EQ(PROT_READ | PROT_EXEC, map_info->flags);
+  EXPECT_TRUE(map_info->name.empty());
+}
+
+TEST_F(LocalUpdatableMapsTest, all_new_maps) {
+  TemporaryFile tf;
+  ASSERT_TRUE(
+      android::base::WriteStringToFile("1000-2000 r-xp 00000 00:00 0\n"
+                                       "a000-f000 r-xp 00000 00:00 0\n",
+                                       tf.path));
+
+  maps_.TestSetMapsFile(tf.path);
+  ASSERT_TRUE(maps_.Reparse());
+  ASSERT_EQ(2U, maps_.Total());
+
+  MapInfo* map_info = maps_.Get(0);
+  ASSERT_TRUE(map_info != nullptr);
+  EXPECT_EQ(0x1000U, map_info->start);
+  EXPECT_EQ(0x2000U, map_info->end);
+  EXPECT_EQ(0U, map_info->offset);
+  EXPECT_EQ(PROT_READ | PROT_EXEC, map_info->flags);
+  EXPECT_TRUE(map_info->name.empty());
+
+  map_info = maps_.Get(1);
+  ASSERT_TRUE(map_info != nullptr);
+  EXPECT_EQ(0xa000U, map_info->start);
+  EXPECT_EQ(0xf000U, map_info->end);
+  EXPECT_EQ(0U, map_info->offset);
+  EXPECT_EQ(PROT_READ | PROT_EXEC, map_info->flags);
+  EXPECT_TRUE(map_info->name.empty());
+
+  auto& saved_maps = maps_.TestGetSavedMaps();
+  ASSERT_EQ(2U, saved_maps.size());
+  map_info = saved_maps[0].get();
+  ASSERT_TRUE(map_info != nullptr);
+  EXPECT_EQ(0x3000U, map_info->start);
+  EXPECT_EQ(0x4000U, map_info->end);
+  EXPECT_EQ(0U, map_info->offset);
+  EXPECT_EQ(PROT_READ | PROT_EXEC, map_info->flags);
+  EXPECT_TRUE(map_info->name.empty());
+
+  map_info = saved_maps[1].get();
+  ASSERT_TRUE(map_info != nullptr);
+  EXPECT_EQ(0x8000U, map_info->start);
+  EXPECT_EQ(0x9000U, map_info->end);
+  EXPECT_EQ(0U, map_info->offset);
+  EXPECT_EQ(PROT_READ | PROT_EXEC, map_info->flags);
+  EXPECT_TRUE(map_info->name.empty());
+}
+
+}  // namespace unwindstack