When activated via 'systemsettings5', clicking on 'Startup and Shutdown' and then 'SDDM', causes a crash under plasma 5.6.5. Running systemsettings5 under a terminal only provides the following output during the crash: rich@graendalwired ~ $ systemsettings5 QDBusArgument: read from a write-only object Aborted
Also note this page from the gentoo forums discussing other items that are likely somehow related to the issue: https://forums.gentoo.org/viewtopic-p-7948384.html#7948384
If the suggestions on the thread file, please attach a backtrace.
Created attachment 441758 [details] backtrace of crash
Looks like the last traceable error in the stack is at #18 in the backtrace
Disabling the "debug" USE flag in dev-qt/*:5 appears to "fix" this...
https://wiki.gentoo.org/wiki/Project:Quality_Assurance/Backtraces#debug_USE_flag "Debug features that are enabled by the USE flag include assertions, debug logs on screen, debug files, leak detection and extra-safe operations (such as scrubbing memory before use). Some of them might be taxing, especially for complex software or software where performance is an important issue. For these reasons, please exercise caution when enabling the debug USE flag, and only consider it a last-chance card." While it is certainly not great that sddm-kcm is crashing under these circumstances, it is also not expected to casually use the debug flag.
(In reply to Richard Ostrow from comment #5) > Disabling the "debug" USE flag in dev-qt/*:5 appears to "fix" this... @qt, thoughts?
(In reply to Michael Palimaka (kensington) from comment #7) > @qt, thoughts? You're hitting an assertion in QtDBus that is compiled only with USE=debug. The question is why the assertion is failing. Could be a bug in qtdbus, could be a bug elsewhere in the stack...
http://code.qt.io/cgit/qt/qtbase.git/tree/src/dbus/qdbusargument.cpp?h=5.7#n141
Qt 5.7.1 is unmasked in tree now. https://gitweb.gentoo.org/repo/gentoo.git/commit/?id=a15cdafa5217ad0a6207da0181be418136c818a5 https://gitweb.gentoo.org/repo/gentoo.git/commit/?id=fe6f8fe62b87846dc84929934b3063b961fbcfcf
Created attachment 482664 [details, diff] 0001-Fix-QDBusArgument-assertion.patch (In reply to Johannes Huber from comment #10) > Qt 5.7.1 is unmasked in tree now. I still get this with qtdbus-5.7.1, so I believe this hasn't been fixed. However, the fix has been committed to the polkit-qt-1 master [1], see more background info in https://bugs.kde.org/show_bug.cgi?id=364524#c5 [1] https://cgit.kde.org/polkit-qt-1.git/commit/?id=fb1667ac9a5437b4784d2806a3e816cbdbe404a5 I've rebased the patch on top of polkit-qt-1-0.112.0 and attached. If I put it into /etc/portage/patches/sys-auth/polkit-qt-0.112.0, the crash does not occur again with dev-qt/qtdbus-5.7.1[debug].
(In reply to Matěj Laitl from comment #11) > Created attachment 482664 [details, diff] [details, diff] > 0001-Fix-QDBusArgument-assertion.patch > > (In reply to Johannes Huber from comment #10) > > Qt 5.7.1 is unmasked in tree now. > > I still get this with qtdbus-5.7.1, so I believe this hasn't been fixed. > > However, the fix has been committed to the polkit-qt-1 master [1], see more > background info in https://bugs.kde.org/show_bug.cgi?id=364524#c5 > > [1] > https://cgit.kde.org/polkit-qt-1.git/commit/ > ?id=fb1667ac9a5437b4784d2806a3e816cbdbe404a5 > > I've rebased the patch on top of polkit-qt-1-0.112.0 and attached. If I put > it into /etc/portage/patches/sys-auth/polkit-qt-0.112.0, the crash does not > occur again with dev-qt/qtdbus-5.7.1[debug]. Thanks a lot for investigating this. I've added a polkit-qt snapshot to the tree which will hopefully solve this for good: https://gitweb.gentoo.org/repo/gentoo.git/commit/?id=39d55767f9fad76d4cb295638caa5a0f718f5f35
(In reply to Michael Palimaka (kensington) from comment #12) > Thanks a lot for investigating this. I've added a polkit-qt snapshot to the > tree which will hopefully solve this for good: > https://gitweb.gentoo.org/repo/gentoo.git/commit/ > ?id=39d55767f9fad76d4cb295638caa5a0f718f5f35 Cool, thanks!
