I revisited my leap 42.1 test machine and today lot of stuff on the kde desktop
was real slow, even alt+f1 console login or su or sudo zypper ref all took
ages.

then even everything on the kde desktop was nonreactive except for the mouse
cursor that still moved and was displayed, and I hit ctrl alt backspace or
something to reset or kill the graphics stack.

eventually I find recent entries of segfaults (via dmesg)

[Mon Feb  8 16:50:51 2016] kactivitymanage[15275]: segfault at 7fe1dce05d10 ip
00007fe1dd04c69a sp 00007ffdc452e3c8 error 4 in
libQt5Sql.so.5.5.1[7fe1dd037000+3f000

[Mon Feb  8 16:36:29 2016] kactivitymanage[929]: segfault at 7fc6daef5d10 ip
00007fc6db13c69a sp 00007ffec5560d38 error 4 in
libQt5Sql.so.5.5.1[7fc6db127000+3f000]



before those there only was a segfault at

[Sat Feb  6 06:54:56 2016] sddm-greeter[377]: segfault at 10 ip
0000000000436f75 sp 00007ffdbe31c3d0 error 4 in sddm-greeter[400000+46000]




and then even longer before that

[Mon Feb  1 09:54:49 2016] kactivitymanage[1806]: segfault at 7ffa0d9fbd10 ip
00007ffa0dc4269a sp 00007ffc11ae3468 error 4 in
libQt5Sql.so.5.5.1[7ffa0dc2d000+3f000]


No more segfaults for this uptime session of the machine.