[vlc-devel] Deadlock in freetype module
Sergey E. Galanov
sgsoftware at mail.ru
Mon Aug 18 19:08:25 CEST 2008
Jean-Baptiste Kempf wrote:
> On Sun, Aug 17, 2008 at 11:11:26PM +0400, Sergey E. Galanov wrote :
>> After upgrading to the latest version of vlc in my gentoo distribution
>> there has appeared a problem: while playing any video file the window
>> with video
>> output remains black, while sound goes normally.
> Is it the 0.9.0-test3 tag or top-of tree git ?
Both of them: I checked it yesterday against the latest snapshot and the
issue was there.
>> When, compiled in debug mode, vlc simply crashes because of mutex
>> assertion failure. This problem is caused by a deadlock situation in the
>> freetype module.
>> Here is a code excerpt from file 'modules/misc/freetype.c':
>> Here we have an obvious deadlock: FontBuilderAttach acquires mutex
>> "fontbuilder", and FontBuilderDone
>> which is being called from that function (via var_TriggerCallback)
>> acquires the same mutex.
>> Perhaps, it is assumed that in this case 'newval.b_bool' is always
>> false, but since it deadlocks, this assumption is wrong :)
>> Of course I don't have any insight into this code and contexts from
>> which it may be called, but it seems to me that the
>> call to var_TriggerCallback is erroneous, since callback should be
>> called when builder thread has finished its work. So I just
>> commented this call. It worked fine for me.
> Is someone skilled to look at it ?
>> With this bug vlc is absolutely unusable.
> This can happen with test versions...
> Best Regards,
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