[GHC] #4820: "Invalid object in isRetainer" when doing retainer profiling in GHC 7 branch

[GHC]

#4820: "Invalid object in isRetainer" when doing retainer profiling in GHC 7
branch
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        Reporter:  dleuschner     |                Owner:
            Type:  bug            |               Status:  new
        Priority:  high           |            Milestone:  7.0.2
       Component:  Profiling      |              Version:  7.10.3
      Resolution:                 |             Keywords:
Operating System:  MacOS X        |         Architecture:  x86_64 (amd64)
 Type of failure:  Runtime crash  |            Test Case:
      Blocked By:                 |             Blocking:
 Related Tickets:                 |  Differential Rev(s):
       Wiki Page:                 |
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Changes (by carter):

 * status:  closed => new
 * resolution:  invalid =>
 * version:  7.0.1 => 7.10.3
 * os:  Linux => MacOS X


Comment:

 On a highly concurrent application at work, we've seen this exact same
 sort of crash when doing retainer profiling.  Don't have a repro yes, but
 this is a real crash.
 Not sure if I can replicate it on 8.0rc but I'll try to poke at it

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Ticket URL: <http://ghc.haskell.org/trac/ghc/ticket/4820#comment:5>
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