[GHC] #11972: Weak pointers can cause segfault

[GHC]

#11972: Weak pointers can cause segfault
-------------------------------------+-------------------------------------
           Reporter:  ryantrinkle    |             Owner:
               Type:  bug            |            Status:  new
           Priority:  normal         |         Milestone:
          Component:  Compiler       |           Version:  8.0.1-rc3
           Keywords:                 |  Operating System:  Unknown/Multiple
       Architecture:  x86_64         |   Type of failure:  Runtime crash
  (amd64)                            |
          Test Case:                 |        Blocked By:
           Blocking:                 |   Related Tickets:
Differential Rev(s):                 |         Wiki Page:
-------------------------------------+-------------------------------------
 The attached program segfaults.  It appears to be nondeterministic, but on
 my machine, it occurs at least 95% of the time.  Some small changes, such
 as removing the bang pattern, cause the segfault to become much less
 likely.

 {{{
 weakPointerSegfault: internal error: ASSERTION FAILED: file
 rts/sm/GCAux.c, line 44

     (GHC version 8.0.0.20160411 for x86_64_unknown_linux)
     Please report this as a GHC bug:
 http://www.haskell.org/ghc/reportabug
 Aborted (core dumped)
 }}}

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Ticket URL: <http://ghc.haskell.org/trac/ghc/ticket/11972>
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