Uninitialised value was created by a stack allocation at QXcbWindow::hide()

********* Start testing of tst_QFiledialog *********
Config: Using QtTest library 5.6.2, Qt 5.6.2 (x86_64-little_endian-lp64 shared (dynamic) debug build; by GCC 5.4.0 20160609)
PASS   : tst_QFiledialog::initTestCase()
==12926== Syscall param writev(vector[...]) points to uninitialised byte(s)
==12926==    at 0x6B1D73D: ??? (syscall-template.S:84)
==12926==    by 0xA71EF28: _xcb_conn_wait (in /usr/lib/x86_64-linux-gnu/libxcb.so.1.1.0)
==12926==    by 0xA71F31C: _xcb_out_send (in /usr/lib/x86_64-linux-gnu/libxcb.so.1.1.0)
==12926==    by 0xA71FA76: _xcb_out_flush_to (in /usr/lib/x86_64-linux-gnu/libxcb.so.1.1.0)
==12926==    by 0xA71FC43: xcb_flush (in /usr/lib/x86_64-linux-gnu/libxcb.so.1.1.0)
==12926==    by 0xD6F0745: QXcbWindow::hide() (qxcbwindow.cpp:886)
==12926==    by 0xD6F0180: QXcbWindow::setVisible(bool) (qxcbwindow.cpp:796)
==12926==    by 0x57D7558: QWindow::setVisible(bool) (qwindow.cpp:525)
==12926==    by 0x5016ACB: QWidgetPrivate::hide_sys() (qwidget.cpp:8086)
==12926==    by 0x5016788: QWidgetPrivate::hide_helper() (qwidget.cpp:8014)
==12926==    by 0x5017095: QWidget::setVisible(bool) (qwidget.cpp:8216)
==12926==    by 0x501669D: QWidget::hide() (qwidget.cpp:7988)
==12926==  Address 0xced4131 is 4,545 bytes inside a block of size 21,152 alloc'd
==12926==    at 0x4C2FB55: calloc (in /usr/lib/valgrind/vgpreload_memcheck-amd64-linux.so)
==12926==    by 0xA71E8DB: xcb_connect_to_fd (in /usr/lib/x86_64-linux-gnu/libxcb.so.1.1.0)
==12926==    by 0xA722610: xcb_connect_to_display_with_auth_info (in /usr/lib/x86_64-linux-gnu/libxcb.so.1.1.0)
==12926==    by 0x9FF9809: _XConnectXCB (in /usr/lib/x86_64-linux-gnu/libX11.so.6.3.0)
==12926==    by 0x9FEA391: XOpenDisplay (in /usr/lib/x86_64-linux-gnu/libX11.so.6.3.0)
==12926==    by 0xD6C98F6: QXcbConnection::QXcbConnection(QXcbNativeInterface*, bool, unsigned int, char const*) (qxcbconnection.cpp:574)
==12926==    by 0xD6D5F16: QXcbIntegration::QXcbIntegration(QStringList const&, int&, char**) (qxcbintegration.cpp:179)
==12926==    by 0x4079703: QXcbIntegrationPlugin::create(QString const&, QStringList const&, int&, char**) (qxcbmain.cpp:50)
==12926==    by 0x57B7118: loadIntegration(QFactoryLoader*, QString const&, QStringList const&, int&, char**) (qplatformintegrationfactory.cpp:56)
==12926==    by 0x57B71D1: QPlatformIntegrationFactory::create(QString const&, QStringList const&, int&, char**, QString const&) (qplatformintegrationfactory.cpp:73)
==12926==    by 0x57C53DF: init_platform(QString const&, QString const&, QString const&, int&, char**) (qguiapplication.cpp:1058)
==12926==    by 0x57C65CE: QGuiApplicationPrivate::createPlatformIntegration() (qguiapplication.cpp:1227)
==12926==  Uninitialised value was created by a stack allocation
==12926==    at 0xD6F066C: QXcbWindow::hide() (qxcbwindow.cpp:874)
==12926== 
PASS   : tst_QFiledialog::directoryEnteredSignal()
PASS   : tst_QFiledialog::cleanupTestCase()
Totals: 3 passed, 0 failed, 0 skipped, 0 blacklisted
********* Finished testing of tst_QFiledialog *********
==12926== 
==12926== HEAP SUMMARY:
==12926==     in use at exit: 345,037 bytes in 5,239 blocks
==12926==   total heap usage: 215,166 allocs, 209,927 frees, 36,573,026 bytes allocated
==12926==