Bug 183500

Update on this issue: 

Here is a very possible reason for the previously mentioned 'dmesg' error, and why Nepomuk didn't run at all:

Recently, I uninstalled "JRE 6u11" (Java User-End Runtime) and installed "OpenJDK6". I did so because "OpenJDK6" was required as a dependency by "Soprano" (a library which provides a highly usable object-oriented C++/Qt4 framework for RDF data), but JRE was NOT required by Soprano as a dependency. Keep in mind, "Soprano" IS required as a dependency by "Kdelibs". So, after installing "OpenJDK6" and uninstalling "JRE" (both cannot be installed at the same time), I rebooted my pc. After running and entering KDE 4.2, in the system tray (for the first time ever) appeared a new icon for "Nepomuk" and it was running as a service, along with "Strigi", another service. I then checked 'dmesg' and no "nepomukservices segfault" error existed anylonger. 

Conclusion: I think the "possible" solution to the original dmesg error for "nepomukservices segfault", and to have both "Nepomuk" and "Strigi" running, you must uninstall "JRE" and install "OpenJDK6". Please look into this. I'm curious, why would Java be a factor in this? Is it because Soprano / Kdelibs needs it to function properly?

My PC (kubuntu 8.10 amd64) crashes about once a day because of this bug. 
I would install OpenJDK6 but JBidwatcher requires specifically SunJRE.

soprano's sesame2 backend works with sun jdk or openjdk. So you should not have a problem there. Yes, ATM Nepomuk needs java to function properly. I am working on a replacesment though.

I also experience this problem on gentoo running kde-4.2.3, QT 4.5.1, compiled with GCC 4.3.3.

Relevant dmesg-Lines:
nepomukservices[7045]: segfault at 7f370000008d ip 00007f37727068d6 sp 00007fff7accf820 error 4 in libQtCore.so.4.5.1[7f37726ab000+1fe000]
nepomukservices[3230] general protection ip:7f1d3d2c18ae sp:7fff4588c3e0 error:0 in libQtCore.so.4.5.1[7f1d3d266000+1fe000]
nepomukservices[3447] general protection ip:7f48fbaac8ae sp:7fff04074bd0 error:0 in libQtCore.so.4.5.1[7f48fba51000+1fe000]
nepomukservices[23717] general protection ip:7f4d92c9e8ae sp:7fff9b268dc0 error:0 in libQtCore.so.4.5.1[7f4d92c43000+1fe000]

nepomuk is not working at all, as far as I can see. Is there any additional information I can provide?

same problem on kde 4.2.3 libQtCore.so.4.5.1 
this crash the X server going back to kdm login

it is very frequently whe I'm using laptop with battery. It's seems that all kde wm slowdown and then crash

I'm on 2.6.29-r5 on x86_64

[ 4018.380802] [drm:i915_get_vblank_counter] *ERROR* trying to get vblank count for disabled pipe 0
[ 4045.638547] nepomukservices[12709]: segfault at 8 ip 00007f9db6457d74 sp 00007fffbea07440 error 4 in libQtCore.so.4.5.1[7f9db6400000+1e4000]
[ 5044.308854] [drm:i915_get_vblank_counter] *ERROR* trying to get vblank count for disabled pipe 0
[ 5065.430240] [drm:i915_get_vblank_counter] *ERROR* trying to get vblank count for disabled pipe 0
[ 5097.409441] nepomukservices[13389]: segfault at 8 ip 00007f10ff14ed74 sp 00007fff07700140 error 4 in libQtCore.so.4.5.1[7f10ff0f7000+1e4000]
[ 5685.163796] [drm:i915_get_vblank_counter] *ERROR* trying to get vblank count for disabled pipe 0
[ 5704.205710] nepomukservices[13783]: segfault at 8 ip 00007f4aea85ad74 sp 00007ffff2e09ed0 error 4 in libQtCore.so.4.5.1[7f4aea803000+1e4000]

Also reported as http://bugs.debian.org/cgi-bin/bugreport.cgi?bug=523740

Please add 523740@bugs.debian.org to CC: list (I couldn't get it added)

In KDE 4.4 we now use Virtuoso as the only supported backend. No more java. Thus, this bug becomes irrelevant.