internal error: throwTo: unrecognised why_blocked value (6.12.1)

Basically just a heads up that I saw ticket #2833 (closed) again:

HaskellTorrent: internal error: throwTo: unrecognised why_blocked value
         (GHC version 6.12.1 for x86_64_unknown_linux)
Please report this as a GHC bug: http://www.haskell.org/ghc/reportabug
Aborted

This is the first time it happens to me, and I make a *lot* of runs. When it happened I had lost all of the context of the running program, sadly, so I have no idea at where to dig. Is there any way I can help you with this? For my own reference, it is this commit from HaskellTorrent that produced the internal RTS error:

commit e7d2fcf771faca6bdd69112825a1281f8b993dfe

I have no reproducible test case for the bug at all either. But I am reporting the problem anyway. Output from the RTS:

jlouis@illithid:~/torrenttest$ ./HaskellTorrent +RTS --info
 [("GHC RTS", "YES")
 ,("GHC version", "6.12.1")
 ,("RTS way", "rts_p")
 ,("Host platform", "x86_64-unknown-linux")
 ,("Host architecture", "x86_64")
 ,("Host OS", "linux")
 ,("Host vendor", "unknown")
 ,("Build platform", "x86_64-unknown-linux")
 ,("Build architecture", "x86_64")
 ,("Build OS", "linux")
 ,("Build vendor", "unknown")
 ,("Target platform", "x86_64-unknown-linux")
 ,("Target architecture", "x86_64")
 ,("Target OS", "linux")
 ,("Target vendor", "unknown")
 ,("Word size", "64")
 ,("Compiler unregisterised", "NO")
 ,("Tables next to code", "YES")
 ]

Trac metadata

Trac field	Value
Version	6.12.1
Type	Bug
TypeOfFailure	OtherFailure
Priority	normal
Resolution	Unresolved
Component	Runtime System
Test case
Differential revisions
BlockedBy
Related
Blocking
CC
Operating system
Architecture