Merge remote-tracking branch 'origin/5.9' into dev

Change-Id: I95266fdaf5c6dc65969bd2e28403da7969367d32

1 files changed, 7 insertions, 0 deletions

diff --git a/src/qml/memory/qv4mm.cpp b/src/qml/memory/qv4mm.cpp
index a0cfd5d925..c4bd1a733f 100644
--- a/src/qml/memory/qv4mm.cpp
+++ b/src/qml/memory/qv4mm.cpp
@@ -165,6 +165,13 @@ struct MemorySegment {
 
         size_t pageSize = WTF::pageSize();
         size = (size + pageSize - 1) & ~(pageSize - 1);
+#if !defined(Q_OS_LINUX) && !defined(Q_OS_WIN)
+        // Linux and Windows zero out pages that have been decommitted and get committed again.
+        // unfortunately that's not true on other OSes (e.g. BSD based ones), so zero out the
+        // memory before decommit, so that we can be sure that all chunks we allocate will be
+        // zero initialized.
+        memset(chunk, 0, size);
+#endif
         pageReservation.decommit(chunk, size);
     }