QRhi: fix data race on rubLogEnabled

* Handle QSG_INFO with the proper macro rather than with an invalid
  const_cast
* Remove the racy bool rubLogEnabled, read the atomic from the
  logging category directly

WARNING: ThreadSanitizer: data race (pid=427588)
  Write of size 1 at 0x7f89d5be2530 by thread T12:
    #0 QRhiImplementation::prepareForCreate(QRhi*, ...) qrhi.cpp:8863
  Previous read of size 1 at 0x7f89d5be2530 by thread T11:
    #0 QRhiResourceUpdateBatchPrivate::free() qrhi.cpp:9907

Pick-to: 6.8
Change-Id: Ied5171ea5bb97372daced8afe3ad894d49961069
Reviewed-by: Laszlo Agocs <laszlo.agocs@qt.io>
(cherry picked from commit 3cc947e98f6237c86160589143e69c13c965e226)

src/gui/rhi/qrhi.cpp

@@ -4,6 +4,7 @@
 #include "qrhi_p.h"
 #include <qmath.h>
 #include <QLoggingCategory>
+#include "private/qloggingregistry_p.h"
 
 #include "qrhinull_p.h"
 #ifndef QT_NO_OPENGL
@@ -24,8 +25,12 @@
 
 QT_BEGIN_NAMESPACE
 
-Q_LOGGING_CATEGORY(QRHI_LOG_INFO, "qt.rhi.general")
+// Play nice with QSG_INFO since that is still the most commonly used
-Q_STATIC_LOGGING_CATEGORY(QRHI_LOG_RUB, "qt.rhi.rub")
+// way to get graphics info printed from Qt Quick apps, and the Quick
+// scenegraph is our primary user.
+Q_LOGGING_CATEGORY_WITH_ENV_OVERRIDE(QRHI_LOG_INFO, "QSG_INFO", "qt.rhi.general")
+
+Q_LOGGING_CATEGORY(QRHI_LOG_RUB, "qt.rhi.rub")
 
 /*!
     \class QRhi
@@ -8779,22 +8784,12 @@ QRhi::~QRhi()
     delete d;
 }
 
-bool QRhiImplementation::rubLogEnabled = false;
-
 void QRhiImplementation::prepareForCreate(QRhi *rhi, QRhi::Implementation impl, QRhi::Flags flags)
 {
     q = rhi;
 
-    // Play nice with QSG_INFO since that is still the most commonly used
-    // way to get graphics info printed from Qt Quick apps, and the Quick
-    // scenegraph is our primary user.
-    if (qEnvironmentVariableIsSet("QSG_INFO"))
-        const_cast<QLoggingCategory &>(QRHI_LOG_INFO()).setEnabled(QtDebugMsg, true);
-
     debugMarkers = flags.testFlag(QRhi::EnableDebugMarkers);
 
-    rubLogEnabled = QRHI_LOG_RUB().isDebugEnabled();
-
     implType = impl;
     implThread = QThread::currentThread();
 }
@@ -9667,7 +9662,7 @@ void QRhiResourceUpdateBatchPrivate::free()
         bufferLargeAllocTotal += op.data.largeAlloc(); // alloc when > 1 KB
     }
 
-    if (rhi->rubLogEnabled) {
+    if (QRHI_LOG_RUB().isDebugEnabled()) {
         qDebug() << "[rub] release to pool upd.batch #" << poolIndex
                 << "/ bufferOps active" << activeBufferOpCount
                 << "of" << bufferOps.count()
@@ -11185,8 +11180,7 @@ QRhi::FrameOpResult QRhi::beginFrame(QRhiSwapChain *swapChain, BeginFrameFlags f
     if (d->inFrame)
         qWarning("Attempted to call beginFrame() within a still active frame; ignored");
 
-    if (d->rubLogEnabled)
+    qCDebug(QRHI_LOG_RUB) << "[rub] new frame";
-        qDebug("[rub] new frame");
 
     QRhi::FrameOpResult r = !d->inFrame ? d->beginFrame(swapChain, flags) : FrameOpSuccess;
     if (r == FrameOpSuccess)
@@ -11336,8 +11330,7 @@ QRhi::FrameOpResult QRhi::beginOffscreenFrame(QRhiCommandBuffer **cb, BeginFrame
     if (d->inFrame)
         qWarning("Attempted to call beginOffscreenFrame() within a still active frame; ignored");
 
-    if (d->rubLogEnabled)
+    qCDebug(QRHI_LOG_RUB) << "[rub] new offscreen frame";
-        qDebug("[rub] new offscreen frame");
 
     QRhi::FrameOpResult r = !d->inFrame ? d->beginOffscreenFrame(cb, flags) : FrameOpSuccess;
     if (r == FrameOpSuccess)

src/gui/rhi/qrhi_p.h

@@ -29,6 +29,7 @@ QT_BEGIN_NAMESPACE
 #define QRHI_RES_RHI(t) t *rhiD = static_cast<t *>(m_rhi)
 
 Q_DECLARE_LOGGING_CATEGORY(QRHI_LOG_INFO)
+Q_DECLARE_LOGGING_CATEGORY(QRHI_LOG_RUB)
 
 class QRhiImplementation
 {
@@ -259,7 +260,6 @@ private:
     QHash<const void *, QRhi::CleanupCallback> keyedCleanupCallbacks;
     QElapsedTimer pipelineCreationTimer;
     qint64 accumulatedPipelineCreationTime = 0;
-    static bool rubLogEnabled;
 
     friend class QRhi;
     friend class QRhiResourceUpdateBatchPrivate;
@@ -374,7 +374,7 @@ public:
         if (!d) {
             d = new QRhiBufferDataPrivate;
         } else if (d->ref != 1) {
-            if (QRhiImplementation::rubLogEnabled)
+            if (QRHI_LOG_RUB().isDebugEnabled())
                 qDebug("[rub] QRhiBufferData %p/%p new backing due to no-copy detach, ref was %d", this, d, d->ref);
             d->ref -= 1;
             d = new QRhiBufferDataPrivate;
@@ -384,7 +384,7 @@ public:
             memcpy(d->data, s, size);
         } else {
             if (d->largeAlloc < size) {
-                if (QRhiImplementation::rubLogEnabled)
+                if (QRHI_LOG_RUB().isDebugEnabled())
                     qDebug("[rub] QRhiBufferData %p/%p new large data allocation %u -> %u", this, d, d->largeAlloc, size);
                 delete[] d->largeData;
                 d->largeAlloc = size;