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  • #3160

Closed
Open
Opened Apr 08, 2009 by ChrisKuklewicz@trac-ChrisKuklewicz

No exception safety in Control.Concurrent.QSem QSemN and SampleVar

Looking at the code for QSem, QSemN, and SampleVar shows they all use a "takeMVar" then "putMVar" programming idiom.

None of these are exception safe. An unlucky killThread will leave the MVar empty and cause the rest of the program to malfunction.

The solution is to rewrite them using withMVar and modifyMVar(_) to prevent the MVar from being left empty in the event of an exception.

Note: QSem also needs the bugfix in #3159 (closed)

Trac metadata
Trac field Value
Version 6.10.2
Type Bug
TypeOfFailure OtherFailure
Priority normal
Resolution Unresolved
Component libraries/base
Test case
Differential revisions
BlockedBy
Related
Blocking
CC
Operating system
Architecture
Assignee
Assign to
7.6.1
Milestone
7.6.1
Assign milestone
Time tracking
None
Due date
None
Reference: ghc/ghc#3160