Fix race condition for SensorManager looper.

Before the fix there could be two background threads started for two
loopers. Add a guard to prevent this from happening.

Test: pass
Bug: 62404135
Change-Id: I8230addaaa6b83670d7b83c96809b00fca95d352

1 files changed, 4 insertions, 0 deletions

diff --git a/services/sensorservice/hidl/SensorManager.cpp b/services/sensorservice/hidl/SensorManager.cpp
index 004a5c5cae..25a3dc50d2 100644
--- a/services/sensorservice/hidl/SensorManager.cpp
+++ b/services/sensorservice/hidl/SensorManager.cpp
@@ -143,6 +143,10 @@ sp<::android::Looper> SensorManager::getLooper() {
             }
 
             std::unique_lock<std::mutex> lock(mutex);
+            if (looper != nullptr) {
+                LOG(INFO) << "Another thread has already set the looper, exiting this one.";
+                return;
+            }
             looper = Looper::prepare(ALOOPER_PREPARE_ALLOW_NON_CALLBACKS /* opts */);
             lock.unlock();