Call Layer::getLayerDebugInfo from the main thread

Fixes an issue where drawing state could be accessed from a binder
thread. The function also mixed current state with drawing state
incorrectly. The function now only retrieves drawing state.

Bug: 150226608
Test: Steps in bug doesn't repro
Test: atest sffakehwc_test
Merged-In: I04daedcb9a890083cc710bab30b295e14b9872ae
Change-Id: I04daedcb9a890083cc710bab30b295e14b9872ae

6 files changed, 11 insertions, 18 deletions

diff --git a/libs/gui/ISurfaceComposer.cpp b/libs/gui/ISurfaceComposer.cpp
index cec86e2a04..fdf56e6e01 100644
--- a/libs/gui/ISurfaceComposer.cpp
+++ b/libs/gui/ISurfaceComposer.cpp
@@ -537,7 +537,7 @@ public:
         return result;
     }
 
-    virtual status_t getLayerDebugInfo(std::vector<LayerDebugInfo>* outLayers) const
+    virtual status_t getLayerDebugInfo(std::vector<LayerDebugInfo>* outLayers)
     {
         if (!outLayers) {
             return UNEXPECTED_NULL;
diff --git a/libs/gui/include/gui/ISurfaceComposer.h b/libs/gui/include/gui/ISurfaceComposer.h
index 0db21a56e3..9d1f3b0055 100644
--- a/libs/gui/include/gui/ISurfaceComposer.h
+++ b/libs/gui/include/gui/ISurfaceComposer.h
@@ -228,7 +228,7 @@ public:
      *
      * Requires the ACCESS_SURFACE_FLINGER permission.
      */
-    virtual status_t getLayerDebugInfo(std::vector<LayerDebugInfo>* outLayers) const = 0;
+    virtual status_t getLayerDebugInfo(std::vector<LayerDebugInfo>* outLayers) = 0;
 };
 
 // ----------------------------------------------------------------------------
diff --git a/libs/gui/tests/Surface_test.cpp b/libs/gui/tests/Surface_test.cpp
index 04686e5ad2..2b4c9019be 100644
--- a/libs/gui/tests/Surface_test.cpp
+++ b/libs/gui/tests/Surface_test.cpp
@@ -625,7 +625,7 @@ public:
         return NO_ERROR;
     }
     status_t injectVSync(nsecs_t /*when*/) override { return NO_ERROR; }
-    status_t getLayerDebugInfo(std::vector<LayerDebugInfo>* /*layers*/) const override {
+    status_t getLayerDebugInfo(std::vector<LayerDebugInfo>* /*layers*/) override {
         return NO_ERROR;
     }
 
diff --git a/services/surfaceflinger/Layer.cpp b/services/surfaceflinger/Layer.cpp
index a062aa1fad..8fd1ce1b60 100644
--- a/services/surfaceflinger/Layer.cpp
+++ b/services/surfaceflinger/Layer.cpp
@@ -1424,7 +1424,7 @@ LayerDebugInfo Layer::getLayerDebugInfo() const {
     LayerDebugInfo info;
     const Layer::State& ds = getDrawingState();
     info.mName = getName();
-    sp<Layer> parent = getParent();
+    sp<Layer> parent = mDrawingParent.promote();
     info.mParentName = (parent == nullptr ? std::string("none") : parent->getName().string());
     info.mType = String8(getTypeId());
     info.mTransparentRegion = ds.activeTransparentRegion;
diff --git a/services/surfaceflinger/SurfaceFlinger.cpp b/services/surfaceflinger/SurfaceFlinger.cpp
index 2c7f8c4c1d..efccaaa8df 100644
--- a/services/surfaceflinger/SurfaceFlinger.cpp
+++ b/services/surfaceflinger/SurfaceFlinger.cpp
@@ -1252,7 +1252,7 @@ status_t SurfaceFlinger::injectVSync(nsecs_t when) {
     return NO_ERROR;
 }
 
-status_t SurfaceFlinger::getLayerDebugInfo(std::vector<LayerDebugInfo>* outLayers) const
+status_t SurfaceFlinger::getLayerDebugInfo(std::vector<LayerDebugInfo>* outLayers)
         NO_THREAD_SAFETY_ANALYSIS {
     IPCThreadState* ipc = IPCThreadState::self();
     const int pid = ipc->getCallingPid();
@@ -1263,20 +1263,13 @@ status_t SurfaceFlinger::getLayerDebugInfo(std::vector<LayerDebugInfo>* outLayer
         return PERMISSION_DENIED;
     }
 
-    // Try to acquire a lock for 1s, fail gracefully
-    const status_t err = mStateLock.timedLock(s2ns(1));
-    const bool locked = (err == NO_ERROR);
-    if (!locked) {
-        ALOGE("LayerDebugInfo: SurfaceFlinger unresponsive (%s [%d]) - exit", strerror(-err), err);
-        return TIMED_OUT;
-    }
-
     outLayers->clear();
-    mCurrentState.traverseInZOrder([&](Layer* layer) {
-        outLayers->push_back(layer->getLayerDebugInfo());
-    });
+    postMessageSync(new LambdaMessage([&]() { 
+            mDrawingState.traverseInZOrder([&](Layer* layer) {
+            outLayers->push_back(layer->getLayerDebugInfo());
+        });
 
-    mStateLock.unlock();
+    }));
     return NO_ERROR;
 }
 
diff --git a/services/surfaceflinger/SurfaceFlinger.h b/services/surfaceflinger/SurfaceFlinger.h
index 1f8c205466..d14e13d8b8 100644
--- a/services/surfaceflinger/SurfaceFlinger.h
+++ b/services/surfaceflinger/SurfaceFlinger.h
@@ -452,7 +452,7 @@ private:
             HdrCapabilities* outCapabilities) const;
     virtual status_t enableVSyncInjections(bool enable);
     virtual status_t injectVSync(nsecs_t when);
-    virtual status_t getLayerDebugInfo(std::vector<LayerDebugInfo>* outLayers) const;
+    virtual status_t getLayerDebugInfo(std::vector<LayerDebugInfo>* outLayers);
 
 
     /* ------------------------------------------------------------------------