FS#61638 - Qt5 update breaks KDE
Attached to Project:
Arch Linux
Opened by Atila Neves (atilaneves) - Tuesday, 05 February 2019, 09:38 GMT
Last edited by Antonio Rojas (arojas) - Thursday, 14 February 2019, 09:10 GMT
Opened by Atila Neves (atilaneves) - Tuesday, 05 February 2019, 09:38 GMT
Last edited by Antonio Rojas (arojas) - Thursday, 14 February 2019, 09:10 GMT
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Details
Description:
KDE wouldn't start on my machine. Since I upgraded the system last night I suspected one of the updates and tried downgrading packages that could affect it. I initially downgraded kwin but that didn't help. So I downgraded all Qt5 updates and the system was usable again. I'm using two monitors with nouveau if that makes a difference. Additional info: These are the package updates that broke my system (from /var/log/pacman.log: [2019-02-04 22:33] [ALPM] upgraded qt5-base (5.12.0-3 -> 5.12.1-1) [2019-02-04 22:33] [ALPM] upgraded qt5-sensors (5.12.0-1 -> 5.12.1-1) [2019-02-04 22:33] [ALPM] upgraded qt5-script (5.12.0-1 -> 5.12.1-1) [2019-02-04 22:33] [ALPM] upgraded qt5-x11extras (5.12.0-1 -> 5.12.1-1) [2019-02-04 22:33] [ALPM] upgraded qt5-multimedia (5.12.0-1 -> 5.12.1-1) [2019-02-04 22:33] [ALPM] upgraded qt5-speech (5.12.0-1 -> 5.12.1-1) [2019-02-04 22:33] [ALPM] upgraded qt5-svg (5.12.0-1 -> 5.12.1-1) [2019-02-04 22:33] [ALPM] upgraded qt5-declarative (5.12.0-1 -> 5.12.1-1) [2019-02-04 22:33] [ALPM] upgraded qt5-graphicaleffects (5.12.0-1 -> 5.12.1-1) [2019-02-04 22:33] [ALPM] upgraded qt5-quickcontrols (5.12.0-1 -> 5.12.1-1) [2019-02-04 22:33] [ALPM] upgraded qt5-quickcontrols2 (5.12.0-1 -> 5.12.1-1) [2019-02-04 22:33] [ALPM] upgraded qt5-location (5.12.0-1 -> 5.12.1-1) [2019-02-04 22:33] [ALPM] upgraded qt5-tools (5.12.0-2 -> 5.12.1-1) [2019-02-04 22:33] [ALPM] upgraded qt5-webchannel (5.12.0-1 -> 5.12.1-1) [2019-02-04 22:33] [ALPM] upgraded qt5-webengine (5.12.0-1 -> 5.12.1-1) [2019-02-04 22:33] [ALPM] upgraded qt5-webkit (5.212.0alpha2-22 -> 5.212.0alpha2-23) [2019-02-04 22:33] [ALPM] upgraded qt5-xmlpatterns (5.12.0-1 -> 5.12.1-1) I tried only downgrading qt5-base first but then I couldn't even start sddm so I downgraded all of them. Steps to reproduce: Try to start KDE. It hangs. |
This task depends upon
Closed by Antonio Rojas (arojas)
Thursday, 14 February 2019, 09:10 GMT
Reason for closing: Fixed
Additional comments about closing: qt5-base 5.10.1-2
Thursday, 14 February 2019, 09:10 GMT
Reason for closing: Fixed
Additional comments about closing: qt5-base 5.10.1-2
I've googled and tried journalctl with both kde and plasmashell but don't seem to have any logs. Where should I be looking?
https://bugs.freedesktop.org/show_bug.cgi?id=109556
which I initially thought was a nouveau kernel driver bug (I'm using modesetting as the X11 driver). However, I learned now that the upgrade responsible was either the qt5 5.12.1 upgrade, or the kwin rebuild, since downgrading those fixes the problem for me as well. Could still be a nouveau kernel bug which can't be triggered by the Qt 5.12.0 code?
Unless you mean something else by "full journal output"? I hope it's logged to the hard drive as well - once KDE hangs I can't do anything, including switching to a terminal.
the symptoms : plasma boots but it is very very slow, with harddisk led blinking constantly, and an error message "/mnt/wd1000 not accessible" occurs, and I can not move my mouse,
if I open a console (ctrl-alt-f2) then I notice that /mnt/wd1000 is accessible, I tried to type dmesg but I didn't notice error message,
if I downgrade qt5 packages then all is ok, no bugs, so there is a serious bug in qt5 5.12.1-1,
I use radeon HD4650 pci-e graphic card, with the radeon driver, I have an old PC (CPU intel quadcore Q9650, motherboard gigabyte GA-P35-DSL3),
I use one screen (no dual monitor), I use the oxygen theme, it's the first time I notice that plasma is totaly broken after a qt5 upgrade, very strange,
I will try to post journalctl log if I find something interesting
so there is an incompatibility between the oxygen theme package (and maybe other themes) and the qt5 packages in version 5.12.1-1
I have created a report in kde bugzilla for oxygen component :
https://bugs.kde.org/show_bug.cgi?id=403978
https://wiki.archlinux.org/index.php/Xinit
https://wiki.archlinux.org/index.php/KDE#From_the_console
My video driver is nouveau.
I can open them in cmd with no errors. Nothing in logs.
KDE on nvidia proprietary driver (ck version).
Downgrading works.
identify the faulty package among the 25 packages of Qt5 can help Qt5 developers to find a fix, the release notes of Qt5 5.12.1 :
https://wiki.qt.io/Qt_5.12.1_Change_Files
see here : https://bbs.archlinux.org/viewtopic.php?pid=1830703
it can explain the extreme slowness (which I interpreted as a hang/frozen desktop), all this need more investigation, but it's not easy as there is no useful logs when the crash/hang occurs
https://bugreports.qt.io/browse/QTBUG-73691
I'm using oxygen. Also I had to downgrade the following packages before i could open system settings to check what theme I'm using:
qt5-base qt5-location qt5-xmlpatterns qt5-webchannel qt5-webkit qt5-webengine qt5-tools qt5-quickcontrols2 qt5-quickcontrols qt5-graphicaleffects qt5-svg qt5-multimedia qt5-speech qt5-x11extras qt5-script qt5-sensors qt5-serialport qt5-serialbus qt5-scxml qt5-remoteobjects qt5-networkauth qt5-imageformats qt5-gamepad qt5-examples qt5-doc qt5-declarative qt5-datavis3d qt5-connectivity qt5-charts qt5-canvas3d qt5-3d pyside2 qt5-translations qt5-virtualkeyboard qt5-wayland qt5-webglplugin qt5-websockets qt5-webview
I want to know if the problem of excessive ram consumption (when using oxygen theme) concerns radeon users (the workaround in Qt5 5.12.1-2 targets only nvidia users with the nouveau driver), and if this problem can be reproduced in virtualbox/qemu, with the gpu generic driver.
I use the proprietary driver nvidia 415.27-4 with the oxygen theme.
currently I am trying a git bisect, in order to find the faulty commit, I will post the results
[9d90c0edac91b35ec96646fd3e6cdd339639ca79] QImage: merge the size calculations with proper (non-UB) checks
https://github.com/qt/qtbase/commit/9d90c0edac91b35ec96646fd3e6cdd339639ca79
If I revert this commit then the bug disapears, all is ok, no memory leak with oxygen theme,
I created a patch which reverts the faulty commit :
https://bugreports.qt.io/secure/attachment/80855/revert_size_calculations_with_proper_non-UB_checks.patch
you can find as attachement a zip file which contains PKGBUILD and the patch, in order to rebuild qt5-base 5.12.1
No problems with Breeze theme and nouveau driver.
https://bugs.archlinux.org/task/61741
all packages (Qt5, plasmashell) are in the last release version
but there are also another conditions (perhaps graphic model card, 3D settings like openGL version, monitor resolution) to meet in order to have the massive memory leak of plasmashell
FS#61741