SurfaceFlinger: add more thread-safety annotations.
As part of debugging a crash in SurfaceFlinger, we became suspicious of
markLayerPendingRemovalLocked because it wasn't annotated with thread
safety annotations. This ended up being a red herring, because
mStateLock is held on all paths into that function. Add some helpers to
MutexUtils.h to require/assert mutexes, and use them to sprinkle some
thread safety annotations to make things more clear.
Test: m surfaceflinger
Change-Id: Ib48433765bb6ffcb351ec10cd5bc89e254b48545
Merged-In: Ib48433765bb6ffcb351ec10cd5bc89e254b48545
diff --git a/services/surfaceflinger/Layer.cpp b/services/surfaceflinger/Layer.cpp
index c2b0a11..905fe40 100644
--- a/services/surfaceflinger/Layer.cpp
+++ b/services/surfaceflinger/Layer.cpp
@@ -72,6 +72,7 @@
#include "LayerProtoHelper.h"
#include "LayerRejecter.h"
#include "MonitoredProducer.h"
+#include "MutexUtils.h"
#include "SurfaceFlinger.h"
#include "TimeStats/TimeStats.h"
#include "TunnelModeEnabledReporter.h"
@@ -254,10 +255,12 @@
auto layersInTree = getRootLayer()->getLayersInTree(LayerVector::StateSet::Current);
std::sort(layersInTree.begin(), layersInTree.end());
- traverse(LayerVector::StateSet::Current, [&](Layer* layer) {
- layer->removeFromCurrentState();
- layer->removeRelativeZ(layersInTree);
- });
+ REQUIRE_MUTEX(mFlinger->mStateLock);
+ traverse(LayerVector::StateSet::Current,
+ [&](Layer* layer) REQUIRES(layer->mFlinger->mStateLock) {
+ layer->removeFromCurrentState();
+ layer->removeRelativeZ(layersInTree);
+ });
}
void Layer::addToCurrentState() {
@@ -936,10 +939,12 @@
mFlinger->mLayersAdded = true;
// set up SF to handle added color layer
if (isRemovedFromCurrentState()) {
+ MUTEX_ALIAS(mFlinger->mStateLock, mDrawingState.bgColorLayer->mFlinger->mStateLock);
mDrawingState.bgColorLayer->onRemovedFromCurrentState();
}
mFlinger->setTransactionFlags(eTransactionNeeded);
} else if (mDrawingState.bgColorLayer && alpha == 0) {
+ MUTEX_ALIAS(mFlinger->mStateLock, mDrawingState.bgColorLayer->mFlinger->mStateLock);
mDrawingState.bgColorLayer->reparent(nullptr);
mDrawingState.bgColorLayer = nullptr;
return true;
diff --git a/services/surfaceflinger/Layer.h b/services/surfaceflinger/Layer.h
index 200baf0..f0c8ad7 100644
--- a/services/surfaceflinger/Layer.h
+++ b/services/surfaceflinger/Layer.h
@@ -409,7 +409,7 @@
virtual ui::LayerStack getLayerStack() const;
virtual bool setMetadata(const LayerMetadata& data);
virtual void setChildrenDrawingParent(const sp<Layer>&);
- virtual bool reparent(const sp<IBinder>& newParentHandle);
+ virtual bool reparent(const sp<IBinder>& newParentHandle) REQUIRES(mFlinger->mStateLock);
virtual bool setColorTransform(const mat4& matrix);
virtual mat4 getColorTransform() const;
virtual bool hasColorTransform() const;
@@ -433,7 +433,8 @@
virtual bool setSidebandStream(const sp<NativeHandle>& /*sidebandStream*/) { return false; };
virtual bool setTransactionCompletedListeners(
const std::vector<sp<CallbackHandle>>& /*handles*/);
- virtual bool setBackgroundColor(const half3& color, float alpha, ui::Dataspace dataspace);
+ virtual bool setBackgroundColor(const half3& color, float alpha, ui::Dataspace dataspace)
+ REQUIRES(mFlinger->mStateLock);
virtual bool setColorSpaceAgnostic(const bool agnostic);
virtual bool setDimmingEnabled(const bool dimmingEnabled);
virtual bool setFrameRateSelectionPriority(int32_t priority);
@@ -715,13 +716,13 @@
/*
* Remove from current state and mark for removal.
*/
- void removeFromCurrentState();
+ void removeFromCurrentState() REQUIRES(mFlinger->mStateLock);
/*
* called with the state lock from a binder thread when the layer is
* removed from the current list to the pending removal list
*/
- void onRemovedFromCurrentState();
+ void onRemovedFromCurrentState() REQUIRES(mFlinger->mStateLock);
/*
* Called when the layer is added back to the current state list.
@@ -899,6 +900,9 @@
virtual bool simpleBufferUpdate(const layer_state_t&) const { return false; }
+ // Exposed so SurfaceFlinger can assert that it's held
+ const sp<SurfaceFlinger> mFlinger;
+
protected:
friend class impl::SurfaceInterceptor;
@@ -974,9 +978,6 @@
*/
virtual Rect getInputBounds() const;
- // constant
- sp<SurfaceFlinger> mFlinger;
-
bool mPremultipliedAlpha{true};
const std::string mName;
const std::string mTransactionName{"TX - " + mName};
diff --git a/services/surfaceflinger/MutexUtils.h b/services/surfaceflinger/MutexUtils.h
index f8be6f3..58f7cb4 100644
--- a/services/surfaceflinger/MutexUtils.h
+++ b/services/surfaceflinger/MutexUtils.h
@@ -50,4 +50,14 @@
const status_t status;
};
+// Require, under penalty of compilation failure, that the compiler thinks that a mutex is held.
+#define REQUIRE_MUTEX(expr) ([]() REQUIRES(expr) {})()
+
+// Tell the compiler that we know that a mutex is held.
+#define ASSERT_MUTEX(expr) ([]() ASSERT_CAPABILITY(expr) {})()
+
+// Specify that one mutex is an alias for another.
+// (e.g. SurfaceFlinger::mStateLock and Layer::mFlinger->mStateLock)
+#define MUTEX_ALIAS(held, alias) (REQUIRE_MUTEX(held), ASSERT_MUTEX(alias))
+
} // namespace android
diff --git a/services/surfaceflinger/SurfaceFlinger.cpp b/services/surfaceflinger/SurfaceFlinger.cpp
index 866958d..7c3ca4b 100644
--- a/services/surfaceflinger/SurfaceFlinger.cpp
+++ b/services/surfaceflinger/SurfaceFlinger.cpp
@@ -4415,6 +4415,7 @@
}
return 0;
}
+ MUTEX_ALIAS(mStateLock, layer->mFlinger->mStateLock);
// Only set by BLAST adapter layers
if (what & layer_state_t::eProducerDisconnect) {
@@ -7304,6 +7305,7 @@
ALOGD("Layer was destroyed soon after creation %p", state.layer.unsafe_get());
return;
}
+ MUTEX_ALIAS(mStateLock, layer->mFlinger->mStateLock);
sp<Layer> parent;
bool addToRoot = state.addToRoot;
diff --git a/services/surfaceflinger/SurfaceFlinger.h b/services/surfaceflinger/SurfaceFlinger.h
index 3e3830d..17541b8 100644
--- a/services/surfaceflinger/SurfaceFlinger.h
+++ b/services/surfaceflinger/SurfaceFlinger.h
@@ -859,7 +859,7 @@
// this layer meaning it is entirely safe to destroy all
// resources associated to this layer.
void onHandleDestroyed(BBinder* handle, sp<Layer>& layer);
- void markLayerPendingRemovalLocked(const sp<Layer>& layer);
+ void markLayerPendingRemovalLocked(const sp<Layer>& layer) REQUIRES(mStateLock);
// add a layer to SurfaceFlinger
status_t addClientLayer(const sp<Client>& client, const sp<IBinder>& handle,