Anybody know how to debug things like this?

Hal Murray hmurray at
Fri Jul 15 02:13:09 UTC 2016

> Seems like a situation made for investigating with Mozilla rr.

Could you please say a bit more?  I don't know anything about Mozilla rr.  
Why is that likely to help me in this case?

I think I have tracked down the problem.  It's trying to start a new thread.  
The clone syscall wasn't on the list, but we have started new threads before. 
 The catch is that the sandboxing doesn't get called until late in the 
initialization procedure.  So the first thread gets created before sandboxing 
turns off the clone syscall.  If you trigger a second thread, that one dies.  
(My test case for that is closing the lid on a laptop for a short time.)

It seemed like a good idea to move the sandboxing up earlier.  The catch is 
that most of the initialization will get done as ntp rather than root, so 
permissions on devices for refclocks and files like ntp.keys need to be fixed.

Anybody see any problems with that?  I think old versions and ntp classic 
will still work running as root.


I figured out the problem with gdb on Raspberry Pi.  It got an illegal 
instruction from SSL before calling main.  It's also got a signal handler.  I 
assume it's a run time test for something.  It works if you continue.

The seccomp stuff doesn't work on Raspberry Pi.  I haven't figured out why.

These are my opinions.  I hate spam.

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