Review Request: Workaround for non-thread-safety of QDBusConnection

[Thiago Macieira]

Em Sexta-feira 28. Maio 2010, às 01.17.47, Lubos Lunak escreveu:
>  For example, openSUSE 11.3 is now entering RC phase and that means that
> only  fixes can enter it, not features or newer non-patchlevel releases.
> Since the fix is in 1.4.0 and openSUSE is at 1.2.8 IIRC, 1.4.0 cannot
> enter openSUSE 11.3, neither now nor later. Now I know what the fix is and
> I need to know what the actual problems are to evaluate and possibly
> justify a request for exception to the rules. With the information given
> so far the fix appears to be rather risky and not even remotely worth a
> problem that has existed for quite a while and is "theoretical".

It's not theoretical. It's quite easy to run into that issue: if the mutex is 
unlocked for a callback, the other thread will not be able to send the 
message. It will fail.

I've seen krunner crashing because of this. That happens because the D-Bus 
calls are sent by several threads in response to the same event: the user 
typing.

Anyway, QtDBus is resistant to the change and wouldn't have problems with the 
patch. The problem are other bindings and low-level apps.

-- 
Thiago Macieira - thiago (AT) macieira.info - thiago (AT) kde.org
  Senior Product Manager - Nokia, Qt Development Frameworks
      PGP/GPG: 0x6EF45358; fingerprint:
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