[GHC] #3875: DPH QuickHull example crashes on SPARC with -N > 1

[GHC]

#3875: DPH QuickHull example crashes on SPARC with -N > 1
-------------------------------+--------------------------------------------
    Reporter:  benl            |        Owner:  benl         
        Type:  bug             |       Status:  assigned     
    Priority:  high            |    Milestone:  6.12.2       
   Component:  Runtime System  |      Version:  6.13         
    Keywords:                  |   Difficulty:               
          Os:  Solaris         |     Testcase:               
Architecture:  sparc           |      Failure:  Runtime crash
-------------------------------+--------------------------------------------

Comment(by benl):

 After compiling quickhull with
 {{{
 ... inplace/bin/ghc-stage2 --make vect.hs -threaded -fdph-par
        -package dph-bench -package-conf ../lib/dph-bench.conf
        -Odph -fforce-recomp -debug
 }}}

 Running
 {{{
 ./vect 10000 +RTS -N16                  -- crashes
 ./vect 10000 +RTS -N16 -qg              -- works, no parallel GC
 ./vect 10000 +RTS -N16 -A100M -H100M -S -- works, only 2 GCs run
 }}}

 And it always crashes in the first GC cycle.

 {{{
 ./vect 100000 +RTS -N2 -S
     Alloc    Copied     Live    GC    GC     TOT     TOT  Page Flts
     bytes     bytes     bytes  user  elap    user    elap
    524688    309168    295340  0.07  0.05    0.08    0.06    0    0  (Gen:
 1)
 Bus Error (core dumped)
 }}}

 Note: `+RTS -DS` (debug sanity) does not sanity check the heap when
 running with `-threaded`. See `rts/sm/Sanity.c`

-- 
Ticket URL: <http://hackage.haskell.org/trac/ghc/ticket/3875#comment:6>
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