I have put a file containing the 4 lstk of 4 threads at http://pkeus.de/~wb/threads.lstk

In the meantime, I tried to use an older 9front 9pc64 kernel, but this didn't help either. 
Unfortunately, I did not make a snapshot before the last sysupdate. 

The next thing I try ,is setting up a fresh clean VM from  a distribution iso : i will report whether this fixes the problem. 
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