I don't think this is caused by ntpd. So many boxes are running that, that if it
ever caused trouble, it would have been fixed already. Can you reproduce it
under Solaris?

Also, removing the question marks from ptrace output is impossible AFAIK. A tool
like ptrace assumes that the processor registers are used according to some C
ABI, but GHC's stack and register layout is totally different from C's.

Creating a tracing tool for GHC-compiled executables seems like a fun project
though :)