From c173a0ea8844a752b665208430e7d7b19d0ce40d Mon Sep 17 00:00:00 2001
From: Le Hoang Quyen <lehoangquyen@chromium.org>
Date: Thu, 6 Apr 2023 08:08:00 +0000
Subject: [PATCH] Fix TRACE_EVENT wasn't thread safe.

TRACE_EVENT uses INTERNAL_TRACE_EVENT_GET_CATEGORY_INFO and
INTERNAL_TRACE_EVENT_GET_CATEGORY_INFO reads and writes to a static
variable on multiple threads.

Fix by using std::atomic for the static variable.

Bug: dawn:1700
Change-Id: I914bb73352e400f0adeafb64518d61099276270d
Reviewed-on: https://dawn-review.googlesource.com/c/dawn/+/123680
Reviewed-by: Corentin Wallez <cwallez@chromium.org>
Kokoro: Kokoro <noreply+kokoro@google.com>
Reviewed-by: Austin Eng <enga@chromium.org>
Commit-Queue: Quyen Le <lehoangquyen@chromium.org>
---
 src/dawn/platform/tracing/TraceEvent.h | 15 +++++++++++----
 1 file changed, 11 insertions(+), 4 deletions(-)

diff --git a/src/dawn/platform/tracing/TraceEvent.h b/src/dawn/platform/tracing/TraceEvent.h
index 76cbc56037..e207b96025 100644
--- a/src/dawn/platform/tracing/TraceEvent.h
+++ b/src/dawn/platform/tracing/TraceEvent.h
@@ -152,6 +152,7 @@
 #ifndef SRC_DAWN_PLATFORM_TRACING_TRACEEVENT_H_
 #define SRC_DAWN_PLATFORM_TRACING_TRACEEVENT_H_
 
+#include <atomic>
 #include <string>
 
 #include "dawn/platform/tracing/EventTracer.h"
@@ -670,10 +671,16 @@
 #define INTERNALTRACEEVENTUID(name_prefix) INTERNAL_TRACE_EVENT_UID2(name_prefix, __LINE__)
 
 // Implementation detail: internal macro to create static category.
-#define INTERNAL_TRACE_EVENT_GET_CATEGORY_INFO(platform, category)    \
-    static const unsigned char* INTERNALTRACEEVENTUID(catstatic) = 0; \
-    if (!INTERNALTRACEEVENTUID(catstatic))                            \
-        INTERNALTRACEEVENTUID(catstatic) = TRACE_EVENT_API_GET_CATEGORY_ENABLED(platform, category);
+#define INTERNAL_TRACE_EVENT_GET_CATEGORY_INFO(platform, category)                            \
+    static std::atomic<const unsigned char*> INTERNALTRACEEVENTUID(atomicCatstatic)(nullptr); \
+    const unsigned char* INTERNALTRACEEVENTUID(catstatic) =                                   \
+        INTERNALTRACEEVENTUID(atomicCatstatic).load(std::memory_order_acquire);               \
+    if (!INTERNALTRACEEVENTUID(catstatic)) {                                                  \
+        INTERNALTRACEEVENTUID(catstatic) =                                                    \
+            TRACE_EVENT_API_GET_CATEGORY_ENABLED(platform, category);                         \
+        INTERNALTRACEEVENTUID(atomicCatstatic)                                                \
+            .store(INTERNALTRACEEVENTUID(catstatic), std::memory_order_release);              \
+    }
 
 // Implementation detail: internal macro to create static category and add
 // event if the category is enabled.