[Scummvm-tracker] [ScummVM :: Bugs] #13953: TINSEL: DW2 - random setMusicSceneDetails() mutex lock-ups when changing scenes

[ScummVM :: Bugs]

#13953: TINSEL: DW2 - random setMusicSceneDetails() mutex lock-ups when changing
scenes
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Reporter:  dwatteau       |       Owner:  (none)
    Type:  defect         |      Status:  new
Priority:  normal         |   Component:  Engine: Tinsel
 Version:                 |  Resolution:
Keywords:  mutex,lock-up  |        Game:  Discworld II
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Comment (by PushmePullyu):

 Interesting find, thanks for the info! This looks like a deadlock due to a
 locking order problem with "Audio::MixerImpl::_mutex" and
 "Tinsel::PCMMusicPlayer::_mutex". The main thread seems to lock them in
 reverse order compared to the audio thread.

 I can reproduce the bug on Linux x86_64 by adding a delayMillis() call in
 setMusicSceneDetails() (see https://github.com/PushmePullyu/scummvm/tree
 /tinsel-dw2-repro-music-deadlock, which also includes a commented out
 potential fix). Starting a new game or changing scenes with this
 immediately deadlocks.

 I will open a PR once I have done some more testing.
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Ticket URL: <https://bugs.scummvm.org/ticket/13953#comment:3>
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