[KDE/Mac] Review Request 121134: make KGlobal reference counting threadsafe

[Milian Wolff]

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as I said before: Did you check whether that is actually the case? Did you add some assertions to see what other thread is calling this code?

I'm not sure whether this is supposed to be threadsafe or not. If it must be threadsafe, you'll also need to make s_allowQuit threadsafe (QAtomicBool).


kdecore/kernel/kglobal.cpp
<https://git.reviewboard.kde.org/r/121134/#comment49264>

    why did you change the conditional? use 
    
        int oldRefCount = s_refCount.fetchAndAddOrdered(-1)
        if (oldRefCount <= 1 && s_allowQuit)


- Milian Wolff


On Nov. 16, 2014, 2:12 p.m., René J.V. Bertin wrote:
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> This is an automatically generated e-mail. To reply, visit:
> https://git.reviewboard.kde.org/r/121134/
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> (Updated Nov. 16, 2014, 2:12 p.m.)
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> 
> Review request for KDE Software on Mac OS X and kdelibs.
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> Repository: kdelibs
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> Description
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> I have been experiencing unexpected exits from KDevelop that were not due to any kind of error in the KDevelop code; it was as if someone told the application to exit normally. This happens mostly on OS X, but also sometimes on Linux.
> I finally traced this to `KGlobal::deref` reaching a zero reference count and invoking `QCoreApplication::quit` when called from one of KDevelop's KJob dtors. There does not appear to be a reference counting mismatch in the code, so the issue might be due to a race condition in KGlobal::ref/deref.
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> This patch introduces thread-safety to KGlobal's reference counting by turning the simple global `static int s_refCount` into a `static QAtomicInt s_refCount`. I consider this an important bug fix regardless of whether it corrects the issue I have with KDevelop.
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> Diffs
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>   kdecore/kernel/kglobal.cpp cf003a4 
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> Diff: https://git.reviewboard.kde.org/r/121134/diff/
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> Testing
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> On OS X 10.6.8 only for now.
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> Thanks,
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> René J.V. Bertin
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>

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