#2560: killThread and getChanContents appear to interact strangely
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Reporter: batterseapower | Owner:
Type: bug | Status: closed
Priority: normal | Milestone: 6.10.2
Component: Runtime System | Version: 6.9
Severity: normal | Resolution: invalid
Keywords: | Difficulty: Unknown
Testcase: | Os: Unknown/Multiple
Architecture: Unknown/Multiple |
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Changes (by simonmar):
* status: new => closed
* resolution: => invalid
Comment:
I've spent a long time staring at this ticket today, and I'm not convinced
there's a bug. `modifyMVar` is exception-safe, and so is
`getChanContents`, as far as I can tell. Ian's point is true, that you
can't guarantee to keep exceptions blocked when calling a library
function, but I don't think that makes anything unsafe in this case.
Exception-safety is all about making sure that `MVars` get replaced if an
exception is raised, and I think that always holds for `modifyMVar` and
`getChanContents`.
No, I suspect there's a bug in the program logic. It just loops when it
gets to a chunk size of 1, and if you look at the definition of
`readWithTimeout`, you can see why. If the chunk size is 1, it just
recurses with the same value for `n`. At least, that's my guess - I don't
fully understand what this program is trying to do.
If you disagree, plesae re-open the bug.
--
Ticket URL: <http://hackage.haskell.org/trac/ghc/ticket/2560#comment:4>
GHC <http://www.haskell.org/ghc/>
The Glasgow Haskell Compiler
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