[kwin] [Bug 368811] Screen freezed when trying to get desktop grid from desktop corner (3d effect)

[Vlad Zagorodniy]

https://bugs.kde.org/show_bug.cgi?id=368811

Vlad Zagorodniy  changed:

   What|Removed |Added

  Latest Commit|https://commits.kde.org/kwi |https://commits.kde.org/kwi
   |n/30ad58f559aa0cfc5dba649be |n/4348cd56834cb17da5aa9d95d
   |387578481e8db32 |16ddc27bf39e0e6

--- Comment #17 from Vlad Zagorodniy  ---
Git commit 4348cd56834cb17da5aa9d95d16ddc27bf39e0e6 by Vlad Zagorodniy, on
behalf of Erik Kurzinger.
Committed on 28/10/2018 at 22:02.
Pushed by vladz into branch 'Plasma/5.12'.

[effects/presentwindows] Avoid potential freeze during fill-gaps

Summary:
When using the natural layout algorithm with the fill-gaps option, a small
error (less than one) is introduced in windows' aspect ratio each time they are
enlarged due to floating-point roundoff.

Currently, the algorithm computes the width and height enlargement factors and
then attempts to enlarge in each of the four possible directions, repeating
until it can't enlarge any windows any further.  Hence, this aspect ratio error
can be multiplied by up to four. Especially for small, long, and narrow
windows, this can result in a total error of greater than one by the end of
that loop iteration. If this occurs, on subsequent iterations the height
enlargement factor might then be computed as negative violating some of the
core assumptions of the algorithm and resulting in the loop iterating endlessly
until one of the window dimensions overflows, freezing the program for up to
several minutes.

To fix this, the height enlargement factor should be re-computed based on the
new width each time the window is enlarged, ensuring the error introduced in
the aspect ratio never exceeds one.
Related: bug 364709, bug 380865

FIXED-IN: 5.15.0

Test Plan:
The most reliable way to reproduce the freeze seems to be to activate the
desktop-grid effect while a tool-tip window is fading in.
Ensure desktop-grid is configured to use present windows, and that present
windows is configured to use the natural layout algorithm with the fill gaps
option selected.

The freeze is still intermittent, but using this method should be able to be
triggered within about 10 tries without this fix.
After applying the fix, the freeze has never been observed.

Reviewers: #kwin, zzag

Reviewed By: #kwin, zzag

Subscribers: graesslin, kwin, zzag

Tags: #kwin

Differential Revision: https://phabricator.kde.org/D16278

M  +15   -3effects/presentwindows/presentwindows.cpp

https://commits.kde.org/kwin/4348cd56834cb17da5aa9d95d16ddc27bf39e0e6

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[kwin] [Bug 368811] Screen freezed when trying to get desktop grid from desktop corner (3d effect)

[Vlad Zagorodniy]

https://bugs.kde.org/show_bug.cgi?id=368811

Vlad Zagorodniy  changed:

   What|Removed |Added

 Resolution|--- |FIXED
   Version Fixed In||5.15.0
  Latest Commit||https://commits.kde.org/kwi
   ||n/30ad58f559aa0cfc5dba649be
   ||387578481e8db32
 Status|CONFIRMED   |RESOLVED

--- Comment #16 from Vlad Zagorodniy  ---
Git commit 30ad58f559aa0cfc5dba649be387578481e8db32 by Vlad Zagorodniy, on
behalf of Erik Kurzinger.
Committed on 20/10/2018 at 15:37.
Pushed by vladz into branch 'master'.

[effects/presentwindows] Avoid potential freeze during fill-gaps

Summary:
When using the natural layout algorithm with the fill-gaps option, a small
error (less than one) is introduced in windows' aspect ratio each time they are
enlarged due to floating-point roundoff.

Currently, the algorithm computes the width and height enlargement factors and
then attempts to enlarge in each of the four possible directions, repeating
until it can't enlarge any windows any further.  Hence, this aspect ratio error
can be multiplied by up to four. Especially for small, long, and narrow
windows, this can result in a total error of greater than one by the end of
that loop iteration. If this occurs, on subsequent iterations the height
enlargement factor might then be computed as negative violating some of the
core assumptions of the algorithm and resulting in the loop iterating endlessly
until one of the window dimensions overflows, freezing the program for up to
several minutes.

To fix this, the height enlargement factor should be re-computed based on the
new width each time the window is enlarged, ensuring the error introduced in
the aspect ratio never exceeds one.
Related: bug 364709, bug 380865

FIXED-IN: 5.15.0

Test Plan:
The most reliable way to reproduce the freeze seems to be to activate the
desktop-grid effect while a tool-tip window is fading in.
Ensure desktop-grid is configured to use present windows, and that present
windows is configured to use the natural layout algorithm with the fill gaps
option selected.

The freeze is still intermittent, but using this method should be able to be
triggered within about 10 tries without this fix.
After applying the fix, the freeze has never been observed.

Reviewers: #kwin, zzag

Reviewed By: #kwin, zzag

Subscribers: graesslin, kwin, zzag

Tags: #kwin

Differential Revision: https://phabricator.kde.org/D16278

M  +15   -3effects/presentwindows/presentwindows.cpp

https://commits.kde.org/kwin/30ad58f559aa0cfc5dba649be387578481e8db32

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[kwin] [Bug 368811] Screen freezed when trying to get desktop grid from desktop corner (3d effect)

[bugzilla_noreply]

https://bugs.kde.org/show_bug.cgi?id=368811

laggerfromrus...@yandex.ru changed:

   What|Removed |Added

 CC||laggerfromrus...@yandex.ru

--- Comment #15 from laggerfromrus...@yandex.ru ---
Looks like I found new way to workaround this issue.
I tried to send SIGABRT (pkill -6 kwin)
and kwin continue normal work after little screen reload.
Way with --replace breaks windows title size for me (make them huge).

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[kwin] [Bug 368811] Screen freezed when trying to get desktop grid from desktop corner (3d effect)

[Maximilian Böhm]

https://bugs.kde.org/show_bug.cgi?id=368811

Maximilian Böhm  changed:

   What|Removed |Added

 CC||m...@elbmurf.de

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[kwin] [Bug 368811] Screen freezed when trying to get desktop grid from desktop corner (3d effect)

[S . Trzmiel]

https://bugs.kde.org/show_bug.cgi?id=368811

S.Trzmiel  changed:

   What|Removed |Added

 CC||x...@x-s.com.pl

--- Comment #14 from S.Trzmiel  ---
Same here, Fedora/Intel IvyBridge gfx. Can't remember when it started exactly
but somwhere around Plasma 5.4. Really can't get what trigger the bug. One day
I can trigger it almost every time and then it can work flawlessly for weeks.
Usual running apps are Firefox, Qupzilla, Kontact, Konsole and Kate. Also
Skype, qTox, Konversation and Amarok in tray.
Kwin usually uses OGl 3.1 renderer, but it also hapend when using OGL 2.0

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[kwin] [Bug 368811] Screen freezed when trying to get desktop grid from desktop corner (3d effect)

[Martin Gräßlin]

https://bugs.kde.org/show_bug.cgi?id=368811

Martin Gräßlin  changed:

   What|Removed |Added

 CC||fl...@mailoo.org

--- Comment #13 from Martin Gräßlin  ---
*** Bug 375268 has been marked as a duplicate of this bug. ***

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[kwin] [Bug 368811] Screen freezed when trying to get desktop grid from desktop corner (3d effect)

[bugzilla_noreply]

https://bugs.kde.org/show_bug.cgi?id=368811

unsuspicious.fakename+kdeb...@gmail.com changed:

   What|Removed |Added

 CC||unsuspicious.fakename+kdebu
   ||g...@gmail.com

--- Comment #12 from unsuspicious.fakename+kdeb...@gmail.com ---
Same problem here, don't have any "weird windows" as far as I can tell. Did you
use some sort of debugging trick to find out which window is the cause or just
trial and error?

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[kwin] [Bug 368811] Screen freezed when trying to get desktop grid from desktop corner (3d effect)

[Martin Gräßlin]

https://bugs.kde.org/show_bug.cgi?id=368811

Martin Gräßlin  changed:

   What|Removed |Added

  Component|effects-window-management   |effects-desktop-grid

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[kwin] [Bug 368811] Screen freezed when trying to get desktop grid from desktop corner (3d effect)

[Elvis Angelaccio via KDE Bugzilla]

https://bugs.kde.org/show_bug.cgi?id=368811

Elvis Angelaccio  changed:

   What|Removed |Added

 CC||elvis.angelac...@kde.org

--- Comment #11 from Elvis Angelaccio  ---
I have a similar issue. Here (Intel graphics,  Xorg session) kwin freezes only 
when I trigger the desktop grid _with_ a second monitor attached. Though it
doesn't always happen, just randomly.

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[kwin] [Bug 368811] Screen freezed when trying to get desktop grid from desktop corner (3d effect)

[Christophe Larsonneur via KDE Bugzilla]

https://bugs.kde.org/show_bug.cgi?id=368811

--- Comment #10 from Christophe Larsonneur  ---
FYI: I stopped the hp myroom tool and all were good until the time I used it
back!

So, another freeze occurs and then, I decided to kill hpmyroom process. But
kwin did not recover from his freeze state. The process is still at 100% CPU,
at this time.  As soon as I have the final coredump, I can send it here also.

I don't know if it can help you guys. Just tell me.

If you need anything else from my side, do not hesitate.

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[kwin] [Bug 368811] Screen freezed when trying to get desktop grid from desktop corner (3d effect)

[Christophe Larsonneur via KDE Bugzilla]

https://bugs.kde.org/show_bug.cgi?id=368811

--- Comment #9 from Christophe Larsonneur  ---
This is where I downloaded the hp myroom tool:

https://www.myroom.hpe.com/Download

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[kwin] [Bug 368811] Screen freezed when trying to get desktop grid from desktop corner (3d effect)

[Martin Gräßlin via KDE Bugzilla]

https://bugs.kde.org/show_bug.cgi?id=368811

--- Comment #8 from Martin Gräßlin  ---
(In reply to Christophe Larsonneur from comment #7)
> Hi,
> 
> I think I found the window that break the 3d effect and causing kwin to
> freeze:
> hp myroom (java app)

where can one get this app?

> 
> Do you think that kwin could do something to avoid this kind of freeze
> because of a window?

yes, once we have a way to reproduce, we can investigate and fix it.

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[kwin] [Bug 368811] Screen freezed when trying to get desktop grid from desktop corner (3d effect)

[Christophe Larsonneur via KDE Bugzilla]

https://bugs.kde.org/show_bug.cgi?id=368811

--- Comment #7 from Christophe Larsonneur  ---
Hi,

I think I found the window that break the 3d effect and causing kwin to freeze:
hp myroom (java app)

Do you think that kwin could do something to avoid this kind of freeze because
of a window?

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[kwin] [Bug 368811] Screen freezed when trying to get desktop grid from desktop corner (3d effect)

[Martin Gräßlin via KDE Bugzilla]

https://bugs.kde.org/show_bug.cgi?id=368811

--- Comment #6 from Martin Gräßlin  ---
> How do you suggest me to identify those windows?

Maybe xwininfo -tree?

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[kwin] [Bug 368811] Screen freezed when trying to get desktop grid from desktop corner (3d effect)

[Martin Gräßlin via KDE Bugzilla]

https://bugs.kde.org/show_bug.cgi?id=368811

Martin Gräßlin  changed:

   What|Removed |Added

 Status|NEEDSINFO   |CONFIRMED
  Component|general |effects-window-management
 Resolution|BACKTRACE   |---
 Ever confirmed|0   |1

--- Comment #4 from Martin Gräßlin  ---
> /usr/src/debug/kwin-5.7.3/effects/presentwindows/presentwindows.cpp:1320

It's looping there? That one should exit. But we have had reports about that
before.

Can you check what kind of windows you have and see whether there is some
window responsible for it. Or some layout?

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[kwin] [Bug 368811] Screen freezed when trying to get desktop grid from desktop corner (3d effect)

[Christophe Larsonneur via KDE Bugzilla]

https://bugs.kde.org/show_bug.cgi?id=368811

--- Comment #3 from Christophe Larsonneur  ---
I have kwin freezing again. Thank gdb, I found it is looping  at 
/usr/src/debug/kwin-5.7.3/effects/presentwindows/presentwindows.cpp:1320

I noticed also that renderer is set to OpenGL 3.1
It looks like OpenGL 2.0 is a little bit faster in term of effects. (or more
smooth) I'm wondering if my issue is not coming from the OpenGL version 3.1.
(with nvidia driver)

I switched to 2.0 and I will see if the issue still happen or not.

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[kwin] [Bug 368811] Screen freezed when trying to get desktop grid from desktop corner (3d effect)

[Martin Gräßlin via KDE Bugzilla]

https://bugs.kde.org/show_bug.cgi?id=368811

Martin Gräßlin  changed:

   What|Removed |Added

 Status|UNCONFIRMED |NEEDSINFO
 Resolution|--- |BACKTRACE

--- Comment #1 from Martin Gräßlin  ---
Unfortunately the backtrace is lacking debug symbols. We don't see where in the
code the crash happens. If able please install debug symbols.

>From what we see the crash happens inside Qt when trying to create a window and
triggers a terminating X error. If we have the line numbers we can check what
goes wrong and forward the bug to Qt.

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