commit 9f330c542b48dc6edba9aeaff3b3f4bf305713f3
author Siarhei Vishniakou <svv@google.com> Tue May 17 05:03:42 2022 -0700
committer Siarhei Vishniakou <svv@google.com> Thu May 19 02:55:32 2022 -0700
tree 2db076dc9a4df968ff52f6b4172bd6a4a95589ce
parent 639db6527174037f5a95385caf9cdd5cbadc56e0

Add lock to protect UnwantedInteractionBlocker

The call to 'dump' may come from any thread, and therefore could cause a
crash. Add a lock to protect this input stage.

To run the test:
adb shell -t "/data/nativetest64/inputflinger_tests/inputflinger_tests --gtest_filter='*Dump*' --gtest_repeat=100000 --gtest_break_on_failure"

Before this patch, the test failed after ~5K - ~13K iterations (took
10-20 seconds to crash).

Bug: 232645962
Test: m inputflinger_tests && adb sync data && <run the test>
Change-Id: I2a199690450bc5bb4a8576aa59075e99d37a531b

services/inputflinger/InputClassifier.h

diff --git a/services/inputflinger/InputClassifier.h b/services/inputflinger/InputClassifier.h
index e2a0bc2..56cf760 100644
--- a/services/inputflinger/InputClassifier.h
+++ b/services/inputflinger/InputClassifier.h
@@ -96,6 +96,9 @@
      */
     virtual void dump(std::string& dump) = 0;
 
+    /* Called by the heatbeat to ensures that the classifier has not deadlocked. */
+    virtual void monitor() = 0;
+
     InputClassifierInterface() { }
     virtual ~InputClassifierInterface() { }
 };
@@ -247,6 +250,7 @@
     void notifyPointerCaptureChanged(const NotifyPointerCaptureChangedArgs* args) override;
 
     void dump(std::string& dump) override;
+    void monitor() override;
 
     ~InputClassifier();
 
@@ -257,7 +261,7 @@
     // Protect access to mMotionClassifier, since it may become null via a hidl callback
     std::mutex mLock;
     // The next stage to pass input events to
-    InputListenerInterface& mListener;
+    QueuedInputListener mQueuedListener;
 
     std::unique_ptr<MotionClassifierInterface> mMotionClassifier GUARDED_BY(mLock);
     std::future<void> mInitializeMotionClassifier GUARDED_BY(mLock);