Bug 404109

SUMMARY
After update (previous update was about couple months ago) I've got memory leak in plasmashell process. It ate more than 8Gb RAM. The largest part allocated as one region. I've tried to debug it and set breakpoint in gdb: break malloc if $rdi>1000000000. After half an hour it stopped here (Thread 9 "QSGRenderThread" hit Breakpoint 1, 0x00007ffff56d28d0 in malloc () from /usr/lib/libc.so.6):
#0  0x00007ffff56d28d0 in malloc () at /usr/lib/libc.so.6
#1  0x00007ffff6037099 in QImageData::create(QSize const&, QImage::Format) () at /usr/lib/libQt5Gui.so.5
#2  0x00007ffff60370ed in QImage::QImage(QSize const&, QImage::Format) () at /usr/lib/libQt5Gui.so.5
#3  0x00007ffff6037126 in QImage::QImage(int, int, QImage::Format) () at /usr/lib/libQt5Gui.so.5
#4  0x00007ffff607a3ce in QRasterPlatformPixmap::resize(int, int) () at /usr/lib/libQt5Gui.so.5
#5  0x00007ffff6079839 in QPlatformPixmap::create(int, int, QPlatformPixmap::PixelType) () at /usr/lib/libQt5Gui.so.5
#6  0x00007ffff6070908 in QPixmap::doInit(int, int, int) () at /usr/lib/libQt5Gui.so.5
#7  0x00007ffff7b4519a in  () at /usr/lib/libKF5Plasma.so.5
#8  0x00007ffff7b461f4 in Plasma::Svg::image(QSize const&, QString const&) () at /usr/lib/libKF5Plasma.so.5
#9  0x00007fffddc38810 in  () at /usr/lib/qt/qml/org/kde/plasma/core/libcorebindingsplugin.so
#10 0x00007ffff7804bd0 in QQuickWindowPrivate::updateDirtyNode(QQuickItem*) () at /usr/lib/libQt5Quick.so.5
#11 0x00007ffff7805044 in QQuickWindowPrivate::updateDirtyNodes() () at /usr/lib/libQt5Quick.so.5
#12 0x00007ffff7806577 in QQuickWindowPrivate::syncSceneGraph() () at /usr/lib/libQt5Quick.so.5
#13 0x00007ffff77abe79 in  () at /usr/lib/libQt5Quick.so.5
#14 0x00007ffff77ad24d in  () at /usr/lib/libQt5Quick.so.5
#15 0x00007ffff77b0b58 in  () at /usr/lib/libQt5Quick.so.5
#16 0x00007ffff5a5e96c in  () at /usr/lib/libQt5Core.so.5
#17 0x00007ffff495fa9d in start_thread () at /usr/lib/libpthread.so.0
#18 0x00007ffff5748b23 in clone () at /usr/lib/libc.so.6

With rdi=0x1ffffffd8.


STEPS TO REPRODUCE
1. Start KDE
2. See kde memory consumption


OBSERVED RESULT
It ates more than 8Gb of memory

EXPECTED RESULT
It ates no more than 200Mb.

SOFTWARE/OS VERSIONS
Linux/KDE Plasma: ArchLinux x64 last update (02/8/2019). KDE 5.14.5-2
KDE Plasma Version: 5.14.5
KDE Frameworks Version: 5.54.0
Qt Version: 5.12.1