From b123f47bbde4d30be44ca02fc369f6ff83dbff8f Mon Sep 17 00:00:00 2001
From: Vishnu Nair <vishnun@google.com>
Date: Mon, 22 Jun 2020 11:52:39 -0700
Subject: 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: I5537c53e8214e2785473839d71fd483d1a3219b6
Change-Id: I04daedcb9a890083cc710bab30b295e14b9872ae
---
 services/surfaceflinger/Layer.cpp          |  2 +-
 services/surfaceflinger/SurfaceFlinger.cpp | 19 ++++++-------------
 services/surfaceflinger/SurfaceFlinger.h   |  2 +-
 3 files changed, 8 insertions(+), 15 deletions(-)

(limited to 'services')

diff --git a/services/surfaceflinger/Layer.cpp b/services/surfaceflinger/Layer.cpp
index 1318bc0b2a..fccaf8166d 100644
--- a/services/surfaceflinger/Layer.cpp
+++ b/services/surfaceflinger/Layer.cpp
@@ -1280,7 +1280,7 @@ LayerDebugInfo Layer::getLayerDebugInfo() const {
     LayerDebugInfo info;
     const 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 = std::string(getTypeId());
     info.mTransparentRegion = ds.activeTransparentRegion_legacy;
diff --git a/services/surfaceflinger/SurfaceFlinger.cpp b/services/surfaceflinger/SurfaceFlinger.cpp
index 6166789fc4..1a25b8230e 100644
--- a/services/surfaceflinger/SurfaceFlinger.cpp
+++ b/services/surfaceflinger/SurfaceFlinger.cpp
@@ -1284,22 +1284,15 @@ 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 {
-    // 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 52655944de..03c3d957fd 100644
--- a/services/surfaceflinger/SurfaceFlinger.h
+++ b/services/surfaceflinger/SurfaceFlinger.h
@@ -432,7 +432,7 @@ private:
                                 HdrCapabilities* outCapabilities) const override;
     status_t enableVSyncInjections(bool enable) override;
     status_t injectVSync(nsecs_t when) override;
-    status_t getLayerDebugInfo(std::vector<LayerDebugInfo>* outLayers) const override;
+    status_t getLayerDebugInfo(std::vector<LayerDebugInfo>* outLayers) override;
     status_t getColorManagement(bool* outGetColorManagement) const override;
     status_t getCompositionPreference(ui::Dataspace* outDataspace, ui::PixelFormat* outPixelFormat,
                                       ui::Dataspace* outWideColorGamutDataspace,
-- 
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