commit 6e2353b814ae81d7c69f38fbd65467c48f3000bf
author Yin-Chia Yeh <yinchiayeh@google.com> Tue Oct 24 16:35:20 2017 -0700
committer Yin-Chia Yeh <yinchiayeh@google.com> Thu Oct 26 16:30:52 2017 -0700
tree a173ba0f0444eace52c93411c2fd538bcde2b480
parent 7a23b30bd0c997ddf5bd3284da43b3efc32bec20

Camera NDK: fix deadlock issues

1. Fix AMessage contains last reference to session
   issue
2. Fix disconnectLocked waits on dead session issue

Test: add some sleeps to make deadlock scenarios pops in CTS
      and then run CTS 100 times.
Bug: 67965633

Change-Id: If0ab9e33de12969dcb5f1d10e96f47f13024f399

camera/ndk/impl/ACameraDevice.h

diff --git a/camera/ndk/impl/ACameraDevice.h b/camera/ndk/impl/ACameraDevice.h
index c0766c5..15dd08d 100644
--- a/camera/ndk/impl/ACameraDevice.h
+++ b/camera/ndk/impl/ACameraDevice.h
@@ -95,7 +95,7 @@
     // device goes into fatal error state after this
     void setCameraDeviceErrorLocked(camera_status_t error);
 
-    void disconnectLocked(); // disconnect from camera service
+    void disconnectLocked(sp<ACameraCaptureSession>& session); // disconnect from camera service
 
     camera_status_t stopRepeatingLocked();
 
@@ -137,6 +137,9 @@
 
     camera_status_t configureStreamsLocked(const ACaptureSessionOutputContainer* outputs);
 
+    // Input message will be posted and cleared after this returns
+    void postSessionMsgAndCleanup(sp<AMessage>& msg);
+
     static camera_status_t getIGBPfromAnw(
             ANativeWindow* anw, sp<IGraphicBufferProducer>& out);
 
@@ -184,7 +187,9 @@
         kWhatCaptureFail,      // onCaptureFailed
         kWhatCaptureSeqEnd,    // onCaptureSequenceCompleted
         kWhatCaptureSeqAbort,  // onCaptureSequenceAborted
-        kWhatCaptureBufferLost // onCaptureBufferLost
+        kWhatCaptureBufferLost,// onCaptureBufferLost
+        // Internal cleanup
+        kWhatCleanUpSessions   // Cleanup cached sp<ACameraCaptureSession>
     };
     static const char* kContextKey;
     static const char* kDeviceKey;
@@ -198,10 +203,16 @@
     static const char* kSequenceIdKey;
     static const char* kFrameNumberKey;
     static const char* kAnwKey;
+
     class CallbackHandler : public AHandler {
       public:
-        CallbackHandler() {}
         void onMessageReceived(const sp<AMessage> &msg) override;
+
+      private:
+        // This handler will cache all capture session sp until kWhatCleanUpSessions
+        // is processed. This is used to guarantee the last session reference is always
+        // being removed in callback thread without holding camera device lock
+        Vector<sp<ACameraCaptureSession>> mCachedSessions;
     };
     sp<CallbackHandler> mHandler;
 
@@ -209,7 +220,7 @@
      * Capture session related members *
      ***********************************/
     // The current active session
-    ACameraCaptureSession* mCurrentSession = nullptr;
+    wp<ACameraCaptureSession> mCurrentSession;
     bool mFlushing = false;
 
     int mNextSessionId = 0;