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  • Glasgow Haskell Compiler
  • GHCGHC
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  • #4245
Closed
Open
Created Aug 07, 2010 by pturnbull@trac-pturnbull

ghci panic: thread blocked indefinitely in an MVar operation

I stumbled across this error today:

phil ~
$ ghci
GHCi, version 6.12.3: http://www.haskell.org/ghc/  :? for help
Loading package ghc-prim ... linking ... done.
Loading package integer-gmp ... linking ... done.
Loading package base ... linking ... done.
Loading package ffi-1.0 ... linking ... done.
Prelude> 
[1]+  Stopped                 ghci
phil ~
$ fg
ghci
^C^C

Prelude> 
ghc: panic! (the 'impossible' happened)
  (GHC version 6.12.3 for i386-apple-darwin):
	thread blocked indefinitely in an MVar operation

Please report this as a GHC bug:  http://www.haskell.org/ghc/reportabug

phil ~
$

Steps to reproduce:

  • start ghci
  • ctrl-z
  • fg
  • ctrl-c
  • ctrl-c
  • enter
  • wait ~2 seconds

I'm not sure if it is related but while waiting for the impossible to happen, any characters typed are not echoed to the screen.

Trac metadata
Trac field Value
Version 6.12.3
Type Bug
TypeOfFailure OtherFailure
Priority normal
Resolution Unresolved
Component GHCi
Test case
Differential revisions
BlockedBy
Related
Blocking
CC
Operating system MacOS X
Architecture x86
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