1 files changed, 14 insertions, 0 deletions
diff --git a/src/corelib/plugin/quuid.cpp b/src/corelib/plugin/quuid.cpp
index f48cc2e..d0c59a4 100644
--- a/src/corelib/plugin/quuid.cpp
+++ b/src/corelib/plugin/quuid.cpp
@@ -577,6 +577,7 @@ QUuid QUuid::createUuid()
 
 QT_BEGIN_INCLUDE_NAMESPACE
 #include "qdatetime.h"
+#include "qthreadstorage.h"
 #include <stdlib.h> // for RAND_MAX
 QT_END_INCLUDE_NAMESPACE
 
@@ -591,6 +592,19 @@ QUuid QUuid::createUuid()
         randbits = r;
     }
 
+    static QThreadStorage<int *> uuidseed;
+    if (!uuidseed.hasLocalData()) {
+        // Seed the PRNG once per thread with a combination of current time, a
+        // stack address and a serial counter (since thread stack addresses are
+        // re-used).
+        int *pseed = new int;
+        static QBasicAtomicInt serial = Q_BASIC_ATOMIC_INITIALIZER(2);
+        qsrand(*pseed = QDateTime::currentDateTime().toTime_t()
+                        + quintptr(&pseed)
+                        + serial.fetchAndAddRelaxed(1));
+        uuidseed.setLocalData(pseed);
+    }
+
     QUuid result;
     uint *data = &(result.data1);
     int chunks = 16 / sizeof(uint);