From 3c64fe30ca6abd82bfe8f478867de0b31181efdc Mon Sep 17 00:00:00 2001
From: Courtney Goeltzenleuchter <courtneygo@google.com>
Date: Thu, 17 Sep 2020 08:27:04 -0600
Subject: [PATCH] Vulkan: need to serialize access to mFenceRecycler

It's possible for multiple threads to touch mFenceRecycler so need to
protect it with a mutex to prevent race conditions.

Bug: b/168744476
Change-Id: I9898d2e9ebf0974581a1074cbda5be41a09cd790
Reviewed-on: https://chromium-review.googlesource.com/c/angle/angle/+/2415401
Reviewed-by: Jamie Madill <jmadill@chromium.org>
Reviewed-by: Tim Van Patten <timvp@google.com>
Commit-Queue: Courtney Goeltzenleuchter <courtneygo@google.com>
---
 src/libANGLE/renderer/vulkan/RendererVk.cpp | 25 +++++++++++++++------
 src/libANGLE/renderer/vulkan/RendererVk.h   |  2 ++
 2 files changed, 20 insertions(+), 7 deletions(-)

diff --git a/src/libANGLE/renderer/vulkan/RendererVk.cpp b/src/libANGLE/renderer/vulkan/RendererVk.cpp
index ed676eb2d..643bc3bd9 100644
--- a/src/libANGLE/renderer/vulkan/RendererVk.cpp
+++ b/src/libANGLE/renderer/vulkan/RendererVk.cpp
@@ -512,7 +512,10 @@ void RendererVk::onDestroy()
 
     mOneOffCommandPool.destroy(mDevice);
 
-    mFenceRecycler.destroy(mDevice);
+    {
+        std::lock_guard<std::mutex> lock(mFenceRecyclerMutex);
+        mFenceRecycler.destroy(mDevice);
+    }
 
     mPipelineLayoutCache.destroy(mDevice);
     mDescriptorSetLayoutCache.destroy(mDevice);
@@ -2205,19 +2208,27 @@ VkResult RendererVk::queuePresent(egl::ContextPriority priority,
 angle::Result RendererVk::newSharedFence(vk::Context *context,
                                          vk::Shared<vk::Fence> *sharedFenceOut)
 {
+    bool gotRecycledFence = false;
     vk::Fence fence;
-    if (mFenceRecycler.empty())
+    {
+        std::lock_guard<std::mutex> lock(mFenceRecyclerMutex);
+        if (!mFenceRecycler.empty())
+        {
+            mFenceRecycler.fetch(&fence);
+            gotRecycledFence = true;
+        }
+    }
+    if (gotRecycledFence)
+    {
+        ANGLE_VK_TRY(context, fence.reset(mDevice));
+    }
+    else
     {
         VkFenceCreateInfo fenceCreateInfo = {};
         fenceCreateInfo.sType             = VK_STRUCTURE_TYPE_FENCE_CREATE_INFO;
         fenceCreateInfo.flags             = 0;
         ANGLE_VK_TRY(context, fence.init(mDevice, fenceCreateInfo));
     }
-    else
-    {
-        mFenceRecycler.fetch(&fence);
-        ANGLE_VK_TRY(context, fence.reset(mDevice));
-    }
     sharedFenceOut->assign(mDevice, std::move(fence));
     return angle::Result::Continue;
 }
diff --git a/src/libANGLE/renderer/vulkan/RendererVk.h b/src/libANGLE/renderer/vulkan/RendererVk.h
index 46e66252a..e86c95054 100644
--- a/src/libANGLE/renderer/vulkan/RendererVk.h
+++ b/src/libANGLE/renderer/vulkan/RendererVk.h
@@ -200,6 +200,7 @@ class RendererVk : angle::NonCopyable
     angle::Result newSharedFence(vk::Context *context, vk::Shared<vk::Fence> *sharedFenceOut);
     inline void resetSharedFence(vk::Shared<vk::Fence> *sharedFenceIn)
     {
+        std::lock_guard<std::mutex> lock(mFenceRecyclerMutex);
         sharedFenceIn->resetAndRecycle(&mFenceRecycler);
     }
 
@@ -336,6 +337,7 @@ class RendererVk : angle::NonCopyable
 
     bool mDeviceLost;
 
+    std::mutex mFenceRecyclerMutex;
     vk::Recycler<vk::Fence> mFenceRecycler;
 
     std::mutex mGarbageMutex;