[GHC] #10414: Buggy behavior with threaded runtime (-N1 working, -N2 getting into <<loop>>)

[GHC]

#10414: Buggy behavior with threaded runtime (-N1 working, -N2 getting into
<<loop>>)
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        Reporter:  exio4             |                   Owner:
            Type:  bug               |                  Status:  new
        Priority:  normal            |               Milestone:
       Component:  Compiler          |                 Version:  7.10.1
      Resolution:                    |                Keywords:
Operating System:  Unknown/Multiple  |            Architecture:
 Type of failure:  Incorrect result  |  Unknown/Multiple
  at runtime                         |               Test Case:
      Blocked By:                    |                Blocking:
 Related Tickets:                    |  Differential Revisions:
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Comment (by rwbarton):

 I also came across this comment in `rts/ThreadPaused.c` (I think it is
 concerning a different scenario):
 {{{
     // NB. Blackholing is *compulsory*, we must either do lazy
     // blackholing, or eager blackholing consistently.  See Note
     // [upd-black-hole] in sm/Scav.c.
 }}}
 Does this mean that every module in the entire program, including all the
 libraries the program links against like base, needs to be compiled with
 the same presence or absence of `-feager-blackholing`? The User's Guide
 doesn't mention anything about this and if that is the case, the flag
 seems essentially unusable except for those who are building their own GHC
 from source. I'm hoping the comment is just worded unclearly.

--
Ticket URL: <http://ghc.haskell.org/trac/ghc/ticket/10414#comment:22>
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