Give DescriptorSetAllocator a mutex

There are memory corruption crashes inside DescriptorSetAllocator with
Android Graphite/Dawn/Vulkan. The class is accessed with MutexProtected
from BindGroupLayoutVk but not from DeviceVk so concurrent access to
member variables on different threads seems possible. Since the class is
reference counted move the mutex inside the class so that calling a
method on any reference is thread safe.

Bug: 368362677
Change-Id: I7ca400555261c75995431d4a4023a571747961ee
Reviewed-on: https://dawn-review.googlesource.com/c/dawn/+/212774
Reviewed-by: Corentin Wallez <[email protected]>
Reviewed-by: Geoff Lang <[email protected]>
Commit-Queue: Kyle Charbonneau <[email protected]>

src/dawn/native/vulkan/BindGroupLayoutVk.h

@@ -94,7 +94,7 @@ class BindGroupLayout final : public BindGroupLayoutInternalBase {
     VkDescriptorSetLayout mHandle = VK_NULL_HANDLE;
 
     MutexProtected<SlabAllocator<BindGroup>> mBindGroupAllocator;
-    MutexProtected<Ref<DescriptorSetAllocator>> mDescriptorSetAllocator;
+    Ref<DescriptorSetAllocator> mDescriptorSetAllocator;
 };
 
 }  // namespace dawn::native::vulkan

src/dawn/native/vulkan/DescriptorSetAllocator.cpp

@@ -94,6 +94,8 @@ DescriptorSetAllocator::~DescriptorSetAllocator() {
 }
 
 ResultOrError<DescriptorSetAllocation> DescriptorSetAllocator::Allocate(BindGroupLayout* layout) {
+    Mutex::AutoLock lock(&mMutex);
+
     if (mAvailableDescriptorPoolIndices.empty()) {
         DAWN_TRY(AllocateDescriptorPool(layout));
     }
@@ -116,6 +118,8 @@ ResultOrError<DescriptorSetAllocation> DescriptorSetAllocator::Allocate(BindGrou
 }
 
 void DescriptorSetAllocator::Deallocate(DescriptorSetAllocation* allocationInfo) {
+    Mutex::AutoLock lock(&mMutex);
+
     DAWN_ASSERT(allocationInfo != nullptr);
     DAWN_ASSERT(allocationInfo->set != VK_NULL_HANDLE);
 
@@ -136,6 +140,8 @@ void DescriptorSetAllocator::Deallocate(DescriptorSetAllocation* allocationInfo)
 }
 
 void DescriptorSetAllocator::FinishDeallocation(ExecutionSerial completedSerial) {
+    Mutex::AutoLock lock(&mMutex);
+
     for (const Deallocation& dealloc : mPendingDeallocations.IterateUpTo(completedSerial)) {
         DAWN_ASSERT(dealloc.poolIndex < mDescriptorPools.size());
 

src/dawn/native/vulkan/DescriptorSetAllocator.h

@@ -31,6 +31,7 @@
 #include <vector>
 
 #include "absl/container/flat_hash_map.h"
+#include "dawn/common/Mutex.h"
 #include "dawn/common/SerialQueue.h"
 #include "dawn/common/vulkan_platform.h"
 #include "dawn/native/Error.h"
@@ -81,6 +82,9 @@ class DescriptorSetAllocator : public ObjectBase {
     };
     SerialQueue<ExecutionSerial, Deallocation> mPendingDeallocations;
     ExecutionSerial mLastDeallocationSerial = ExecutionSerial(0);
+
+    // Used to guard all public member functions.
+    Mutex mMutex;
 };
 
 }  // namespace dawn::native::vulkan