D28889: Avoid crash in KWin::DrmOutput::updateCursor

meven created this revision.
meven added reviewers: KWin, zzag, davidedmundson.
Herald added a project: KWin.
Herald added a subscriber: kwin.
meven requested review of this revision.

REVISION SUMMARY
  BUG: 420077
  
  Sample stack traces :
  
  From bug:
  
  #2  QImage::copy (this=this@entry=0x558117775e20, r=...) at image/qimage.cpp:1172
  #3  0x00007f22d0a24cdf in QImage::detach (this=this@entry=0x558117775e20) at image/qimage.cpp:1091
  #4  0x00007f22d0a25ae0 in QImage::fill (this=0x558117775e20, color=...) at image/qimage.cpp:1806
  #5  0x00007f22d0a25f5f in QImage::fill (this=this@entry=0x558117775e20, color=color@entry=Qt::transparent) at image/qimage.cpp:1780
  #6  0x00007f22bf3bdffd in KWin::DrmOutput::updateCursor (this=0x5581176fb780) at ./plugins/platforms/drm/drm_output.cpp:175
  #7  0x00007f22bf3b0e55 in KWin::DrmBackend::updateCursor (this=0x558117669b60) at ./plugins/platforms/drm/drm_backend.cpp:701
  
  Localy reproduced:
  
  #0  0x00007f360611e159 in KWayland::Server::OutputDeviceInterface::transform() const (this=<optimized out>)
  
    at /home/meven/kde/src/kwayland/src/server/outputdevice_interface.cpp:590
  
  #1  0x00007f3607438059 in KWin::AbstractWaylandOutput::transform() const (this=this@entry=0x5645bed10f90) at /home/meven/kde/src/kwin/abstract_wayland_output.cpp:317
  #2  0x00007f35ecd8acd3 in KWin::DrmOutput::matrixDisplay(QSize const&) const (this=0x5645bed10f90, s=...)
  
    at /home/meven/kde/src/kwin/plugins/platforms/drm/drm_output.cpp:155
  
  #3  0x00007f35ecd8efa9 in KWin::DrmOutput::updateCursor() (this=<optimized out>) at /home/meven/kde/src/kwin/plugins/platforms/drm/drm_output.cpp:179
  #4  0x00007f35ecd81db5 in KWin::DrmBackend::updateCursor() (this=0x5645bec743a0) at /home/meven/kde/src/kwin/plugins/platforms/drm/drm_backend.cpp:701
  #5  0x00007f36049e7fe7 in  () at /usr/lib/x86_64-linux-gnu/libQt5Core.so.5
  #6  0x00007f36075ee43f in KWin::Cursors::currentCursorChanged(KWin::Cursor*) (this=<optimized out>, _t1=<optimized out>)
  
    at /home/meven/kde/build/kwin/kwin_autogen/EWIEGA46WW/moc_cursor.cpp:385

TEST PLAN
  Could not reproduce

REPOSITORY
  R108 KWin

BRANCH
  master

REVISION DETAIL
  https://phabricator.kde.org/D28889

AFFECTED FILES
  plugins/platforms/drm/drm_output.cpp

To: meven, #kwin, zzag, davidedmundson
Cc: kwin, Orage, cacarry, LeGast00n, The-Feren-OS-Dev, cblack, jraleigh, zachus, fbampaloukas, mkulinski, ragreen, jackyalcine, iodelay, crozbo, bwowk, ZrenBot, ngraham, alexeymin, himcesjf, lesliezhai, ali-mohamed, hardening, romangg, jensreuterberg, abetts, sebas, apol, ahiemstra, mart