Sometimes I'm discovering next message in dmesg after logging in: dmesg | grep -i error [ 217.633672] kactivitymanage[1884]: segfault at 7f1964027cd0 ip 00007f19590b61b1 sp 00007ffd161559a8 error 4 in libQt5Sql.so.5.4.2[7f19590a2000+3f000] [ 252.036134] kactivitymanage[2739]: segfault at 7f4ba00e5cd0 ip 00007f4ba008f1b1 sp 00007ffde6da54c8 error 4 in libQt5Sql.so.5.4.2[7f4ba007b000+3f000] It is also accompanied by a fall in the X server: when I logged in system it fell, then I logged in again but it fell again. After that I found 'kactivitymanage segfault' massage in dmesg. Reproducible: Sometimes Kubuntu 14.10 Linux 4.1.0-3 x86_64 kactivities 5.13.0
Oh, sorry, I'm using Kubuntu 15.10 Wily
Created attachment 94273 [details] dmesg
Created attachment 94274 [details] syslog
Created attachment 94275 [details] Xorg.0.log
*** This bug has been marked as a duplicate of bug 348194 ***
I do not think that this is a real duplicate. On my system logout works perfectly well. But sometimes plasma just freezes. Only the mouse cursor movement works. When I switch to a text console and look into 'dmesg -THuk' I see this segfault right before the freeze. The linked bug is about kactivitymanage segfault on logout and not during work. So something is happening that triggers the segfault outside the scope of the other bug. (This does not mean that there is a bug in libQt5Sql.so.5.5.0, there certainly is.)
If anybody came her, like me, because they found kactivitymanage segfault in dmesg right before Plasma froze on there systems, I do no longer think that this is more than a coincidence. The Plasma Freeze is more likely related to bug 338999.