Error exit code 11.

I read the earlier thread on signal 11 (may 2010) and understand that, but
it does not seem to be my problem.

I rarely see this, but today it came in a bunch. About the time I was
closing down a VMware session (several virtual machines).
Boinc is running native, not in a VM. Ubuntu 10.10 64bit. 12 cores.
(linux reports 24 cpus, but that is normal when hyperthreading
is turned on in the BIOS).

Notice that Einstein (also always running) never hits a Signal 11.

A dense listing of today's signal 11:

task wu computer

1883293269 731424713 5766757 24 Apr 2011 | 19:58:26 UTC 24 Apr 2011 | 20:28:44 UTC Error while computing 659.90 659.90 --- SETI@home Enhanced v5.28
1883265962 731411449 5766757 24 Apr 2011 | 19:24:07 UTC 24 Apr 2011 | 20:28:44 UTC Error while computing 2,740.17 2,740.17 --- SETI@home Enhanced v5.28
1883209014 731383867 5766757 24 Apr 2011 | 18:13:04 UTC 24 Apr 2011 | 20:28:44 UTC Error while computing 5,304.65 5,304.65 --- SETI@home Enhanced v5.28
1883200502 731379729 5766757 24 Apr 2011 | 18:02:46 UTC 24 Apr 2011 | 20:28:44 UTC Error while computing 7,093.05 7,093.05 --- SETI@home Enhanced v5.28
1883196093 731377569 5766757 24 Apr 2011 | 17:57:03 UTC 24 Apr 2011 | 20:28:44 UTC Error while computing 7,578.98 7,578.98 --- SETI@home Enhanced v5.28
1883168212 731368764 5766757 24 Apr 2011 | 17:16:08 UTC 24 Apr 2011 | 20:28:44 UTC Error while computing 10,024.36 10,024.36 --- SETI@home Enhanced v5.28
1883164393 731366985 5766757 24 Apr 2011 | 17:10:58 UTC 24 Apr 2011 | 20:28:44 UTC Error while computing 10,607.84 10,607.84 --- SETI@home Enhanced v5.28
1883106389 731339020 5766757 24 Apr 2011 | 16:02:42 UTC 24 Apr 2011 | 20:28:44 UTC Error while computing 14,669.16 14,652.88 --- SETI@home Enhanced v5.28
1877748033 728931864 5766757 20 Apr 2011 | 4:47:42 UTC 20 Apr 2011 | 4:59:56 UTC Error while computing 669.15 669.15 --- SETI@home Enhanced v5.28
1866828118 724023891 5766757 10 Apr 2011 | 23:44:22 UTC 11 Apr 2011 | 1:50:15 UTC Error while computing 3,007.91 3,001.11 --- SETI@home Enhanced v5.28
1866828116 724023881 5766757 10 Apr 2011 | 23:44:22 UTC 11 Apr 2011 | 1:50:15 UTC Error while computing 3,021.05 3,014.18 --- SETI@home Enhanced v5.28
1861593646 721654533 5766757 6 Apr 2011 | 23:33:23 UTC 7 Apr 2011 | 2:18:09 UTC Error while computing 6,935.50 6,917.36 --- SETI@home Enhanced v5.28
1837196069 710486311 5766757 12 Mar 2011 | 17:34:18 UTC 12 Mar 2011 | 17:39:24 UTC Error while computing 4,650.80 4,650.80 --- SETI@home Enhanced v5.28

I just turned on core file recording (putting them
in /tmp/corefiles using /proc/sys/kernel/core_pattern) in case having
corefiles will help at some point.

One time I had a problem like this I booted-into the memory-tester
and ran memory tests 8 hours but no errors showed up.

I generate almost exclusively good results. So it distresses to
generate errors.
Suggestions?

More failures at 19:01 UTC Apr 25. No core files. Darn. The boinc
user is not getting ulimit -c unlimited set. No messages
in boincmgr about this.

No records in /var/log (linux log files). Nor in /var/lib/boinc-client
or its subdirectories (boinc logs are there) of failures or the tasks.
Aside from rare older instances of Signal 15. That I can find.

One task at exactly the same time as todays failures (distinct from yesterdays),
19:01:18 UTC ended normally,
credit pending
task wu computer
1884430753 731929460 5766757