Slackware 14.0 RC : KDE kwin keeps crashing at startup
Upgraded a 13.37 system in KVM/QEMU to 14.00 using slackpkg and tried to login into KDE. It first seems to start fine, but after having seen the first 5 icons kwin seems to crash and I endup with 3 crash dumps (one from kdeinit4 and 2 from kwin) and a suggestion to use fvwm2 instead.
I then tried the following :
1) Created a new VM on KVM/AQEMU and made a fresh install from a 14.00 ISO. Same problem when trying to start KDE/kwin (both as root and as ordinary user).
2) I then tried to use Xrender instead of OpenGL : Same problem.
3) I then tried to use remote X session using XDMCP and Xephyr on the host computer : Same problem.
4) I then tried a fresh install of 14.00 on Virtualbox. Guess : same problem !
5) I then tried a suggestion I found elsewhere and added
I am already struggling with this for a day now and am out of tricks/ideas. Anyone who has a solution/workaround for this ?
If I can't get this working we cannot upgrade our Slackware 13.37 to Slackware 14.00 as a reliable KDE is crucial for us.
Maybe same problem in virtualbox?
No, if it is the same problem it should work using Xephyr / XDMCP unless this combination suffers from the same problem as the virtual machines. IS there anyone with a working KDE/Slack 14 who can confirm that Xephyr / XDMCP works fine for them or not ?
BTW: I also tried a Debian Wheezy install on the same KVM/QEMU and there KDE works fine. Wheezy has Qt 4.8.2 and Kwin 4.8.4 which is virtually the same as in Slackware 14 (Qt 4.8.2 and Kwin 4.8.5) so it is either the minor update to 4.8.5 or something specific inside Slackware that causes these crashes.
Small update :
I now installed Slack 14 on a real computer system (old P4) and this time KDE works fine !!!
So, the problem seems to be related only to Virtual machines, but imo it can not be a problem of the Xserver
or else it should work if using a remote Xserver to connect using XDMCP as I did using Xephyr but correct me if you think I am wrong ...
Anyway : Kwin crashes on these virtual machines in memcpy_sse2 with a segmentation fault and that is imo not related to anything that has to do with Compositing.
Thread 1 (Thread 0x7f57a6e7d7c0 (LWP 2693)):
#5 0x00007f579f7898b1 in __memcpy_sse2 () from /lib64/libc.so.6
#6 0x00007f57a36a4286 in ?? () from /usr/lib64/qt/lib/libQtScript.so.4
#7 0x00007f57a36a1dde in ?? () from /usr/lib64/qt/lib/libQtScript.so.4
#8 0x00007f57a36b769c in ?? () from /usr/lib64/qt/lib/libQtScript.so.4
#9 0x00007f57a36b3b53 in ?? () from /usr/lib64/qt/lib/libQtScript.so.4
#10 0x00007f57a3700518 in ?? () from /usr/lib64/qt/lib/libQtScript.so.4
#11 0x00007f57a3700bcc in ?? () from /usr/lib64/qt/lib/libQtScript.so.4
#12 0x00007f57a37a1030 in ?? () from /usr/lib64/qt/lib/libQtScript.so.4
#13 0x00007f57a37a2026 in QScriptEngine::QScriptEngine() () from /usr/lib64/qt/lib/libQtScript.so.4
#14 0x00007f57a6a485fd in ?? () from /usr/lib64/libkdeinit4_kwin.so
#15 0x00007f57a69d7bc5 in kdemain () from /usr/lib64/libkdeinit4_kwin.so
#16 0x00007f579f71ba95 in __libc_start_main () from /lib64/libc.so.6
There are suggestions that it may be related to CPU family or video card - while they reported to encounter the error on machines with Intel video card and Intel Core 2 CPUs, my laptop has AMD Turion 64 ML-34 CPU and ATI Radeon Xpress 200M integrated video card.
FYI : I also installed Debian Wheezy on the same KVM/Qemu virtual machine. Debian Wheezy has the same QT and KDE major version numbers and there I don't see any problems with kwin. As this is the same hardware I don't expect it to be a a (virtual) hardware issue. Only possiblility could be that the compiler options used on Slack and Debian may have been slightly different ?
Tomac: In the thread you mention it seems that Qt was fixed : it may be a good idea to include this updated minor release of QT in Slackware 14.0 final ?
I increased the amount of memory in the virtual machine to 3 GB and everything works fine now !!! No more nasty kwin crashes !
This was suggested in the thread that tomac pointed out and I just thought let's give it a try. So, the bug in this version of Qt only becomes apparent for systems with limited memory, no matter if they are virtual or not.
I consider the problem as solved, although it may be worth to include an improved version of Qt in the final release of Slack.
Thanks for reading/replying, especially Tomac.pl
I get those crashes on a laptop every time I try to start KDE. This thing started after the last update to KDE 14.0RC3
So actually, it wasn't the matter of an update to QT library, but of removing a patch that was previously applied to it.
I think this could be the reason why it works on Debian Wheezy - however, I don't know if the QT4 packages with this patch ever reached Wheezy or if they stayed in Debian Sid only.
I compared patches used to fix JIT issue in Debian and Slackware. I found them under the following locations:
Slackware patch: ftp://ftp.slackware.pl/pub/slackware....crash.diff.gz
Debian patch: http://anonscm.debian.org/gitweb/?p=...1fef79566caf64 - can be found through the history of qt4-x11 package at: http://anonscm.debian.org/gitweb/?p=....git;a=summary
Both patches contain changes made to the same set of source files - however, the order of files is different in them, making it bit difficult to compare them. After sorting files in both patches (sorted versions in attachment) and comparing their contents, it looks like they are essentially the same - the Debian one seems to contain some hints at "@@" lines (not sure what they exactly are). So, in my opinion, the problems that Debian folks encountered were caused by essentially the same patch as the one used in Slackware. After removing the patch from Debian package, issues didn't occur anymore for them.
On the other hand, the patch itself fixes some other issues, so probably making decision whether this patch should stay or not won't be an easy one :|
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