Changeset 57076 in vbox for trunk

Timestamp:

Jul 24, 2015 6:43:41 PM (9 years ago)

Author:

vboxsync

Message:

FE/Qt: 7948: Medium-enumeration handler cleanup deadlock: Do not lock-for-read (since locking-for-write is possible), just try instead.

File:

• trunk/src/VBox/Frontends/VirtualBox/src/globals/VBoxGlobal.cpp (modified) (5 diffs)

trunk/src/VBox/Frontends/VirtualBox/src/globals/VBoxGlobal.cpp

@@ -147 +147 @@
 # include <QNetworkProxy>
 #endif /* VBOX_GUI_WITH_NETWORK_MANAGER */
-#include <QReadLocker>
 #include <QSettings>
 #include <QStyleOptionSpinBox>
@@ -1548 +1547 @@
 void VBoxGlobal::createMedium(const UIMedium &medium)
 {
-    /* Create medium in medium-enumerator: */
-    QReadLocker cleanupRacePreventor(&m_mediumEnumeratorDtorRwLock);
-    if (m_pMediumEnumerator)
-        m_pMediumEnumerator->createMedium(medium);
+    if (m_mediumEnumeratorDtorRwLock.tryLockForRead())
+    {
+        /* Create medium in medium-enumerator: */
+        if (m_pMediumEnumerator)
+            m_pMediumEnumerator->createMedium(medium);
+        m_mediumEnumeratorDtorRwLock.unlock();
+    }
 }
 
 void VBoxGlobal::deleteMedium(const QString &strMediumID)
 {
-    /* Delete medium from medium-enumerator: */
-    QReadLocker cleanupRacePreventor(&m_mediumEnumeratorDtorRwLock);
-    if (m_pMediumEnumerator)
-        m_pMediumEnumerator->deleteMedium(strMediumID);
+    if (m_mediumEnumeratorDtorRwLock.tryLockForRead())
+    {
+        /* Delete medium from medium-enumerator: */
+        if (m_pMediumEnumerator)
+            m_pMediumEnumerator->deleteMedium(strMediumID);
+        m_mediumEnumeratorDtorRwLock.unlock();
+    }
 }
 
@@ -1734 +1739 @@
         return;
 
-    /* Redirect request to medium-enumerator: */
-    QReadLocker cleanupRacePreventor(&m_mediumEnumeratorDtorRwLock);
-    if (m_pMediumEnumerator)
-        m_pMediumEnumerator->enumerateMediums();
+    if (m_mediumEnumeratorDtorRwLock.tryLockForRead())
+    {
+        /* Redirect request to medium-enumerator: */
+        if (m_pMediumEnumerator)
+            m_pMediumEnumerator->enumerateMediums();
+        m_mediumEnumeratorDtorRwLock.unlock();
+    }
 }
 
@@ -1749 +1757 @@
 UIMedium VBoxGlobal::medium(const QString &strMediumID) const
 {
-    /* Redirect call to medium-enumerator: */
-    QReadLocker cleanupRacePreventor(&m_mediumEnumeratorDtorRwLock);
-    if (m_pMediumEnumerator)
-        return m_pMediumEnumerator->medium(strMediumID);
+    if (m_mediumEnumeratorDtorRwLock.tryLockForRead())
+    {
+        /* Redirect call to medium-enumerator: */
+        UIMedium result;
+        if (m_pMediumEnumerator)
+            result = m_pMediumEnumerator->medium(strMediumID);
+        m_mediumEnumeratorDtorRwLock.unlock();
+        return result;
+    }
     return UIMedium();
 }
@@ -1758 +1771 @@
 QList<QString> VBoxGlobal::mediumIDs() const
 {
-    /* Redirect call to medium-enumerator: */
-    QReadLocker cleanupRacePreventor(&m_mediumEnumeratorDtorRwLock);
-    if (m_pMediumEnumerator)
-        return m_pMediumEnumerator->mediumIDs();
+    if (m_mediumEnumeratorDtorRwLock.tryLockForRead())
+    {
+        /* Redirect call to medium-enumerator: */
+        QList<QString> result;
+        if (m_pMediumEnumerator)
+            result = m_pMediumEnumerator->mediumIDs();
+        m_mediumEnumeratorDtorRwLock.unlock();
+        return result;
+    }
     return QList<QString>();
 }