#10545: Deadlock in the threaded RTS
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Reporter: simonmar | Owner: simonmar
Type: bug | Status: new
Priority: highest | Milestone: 7.10.2
Component: Runtime System | Version: 7.10.1
Resolution: | Keywords:
Operating System: Unknown/Multiple | Architecture:
Type of failure: None/Unknown | Unknown/Multiple
Blocked By: | Test Case:
Related Tickets: | Blocking:
| Differential Revisions:
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Comment (by Simon Marlow ):
In [changeset:"111ba4beda4ffc48381723da12e5b237d7f9ac59/ghc"]:
{{{
#!CommitTicketReference repository="ghc"
revision="111ba4beda4ffc48381723da12e5b237d7f9ac59"
Fix deadlock (#10545)
yieldCapability() was not prepared to be called by a Task that is not
either a worker or a bound Task. This could happen if we ended up in
yieldCapability via this call stack:
performGC()
scheduleDoGC()
requestSync()
yieldCapability()
and there were a few other ways this could happen via requestSync.
The fix is to handle this case in yieldCapability(): when the Task is
not a worker or a bound Task, we put it on the returning_workers
queue, where it will be woken up again.
Summary of changes:
* `yieldCapability`: factored out subroutine waitForWorkerCapability`
* `waitForReturnCapability` renamed to `waitForCapability`, and
factored out subroutine `waitForReturnCapability`
* `releaseCapabilityAndQueue` worker renamed to `enqueueWorker`, does
not take a lock and no longer tests if `!isBoundTask()`
* `yieldCapability` adjusted for refactorings, only change in behavior
is when it is not a worker or bound task.
Test Plan:
* new test concurrent/should_run/performGC
* validate
Reviewers: niteria, austin, ezyang, bgamari
Subscribers: thomie, bgamari
Differential Revision: https://phabricator.haskell.org/D997
GHC Trac Issues: #10545
}}}
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Ticket URL: http://ghc.haskell.org/trac/ghc/ticket/10545#comment:1
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