[Webkit-unassigned] [Bug 147085] New: -[AVPlayerItem currentTime] and -[AVPlayer isExternalPlaybackActive] deadlock

[bugzilla-daemon at webkit.org]

https://bugs.webkit.org/show_bug.cgi?id=147085

            Bug ID: 147085
           Summary: -[AVPlayerItem currentTime] and -[AVPlayer
                    isExternalPlaybackActive] deadlock
    Classification: Unclassified
           Product: WebKit
           Version: 528+ (Nightly build)
          Hardware: Unspecified
                OS: Unspecified
            Status: NEW
          Severity: Normal
          Priority: P2
         Component: Web Audio
          Assignee: webkit-unassigned at lists.webkit.org
          Reporter: adachan at apple.com
                CC: crogers at google.com

Repro steps:
https://files.scene.org/get/parties/2015/solskogen15/demo_newschool/primitive-_-i_want_to_see_other_worlds.html.zip

Extract, open the HTML
In Safari, for “Fullscreen?” click “No”
Web process hangs in MediaPlayerPrivateAVFoundationObjC::currentMediaTime()

The main thread is stuck here:
#0    0x00007fff8b613f02 in __psynch_mutexwait ()
...
#6    0x00007fff9ad38eb3 in -[AVPlayerItem currentTime] ()
#7    0x0000000111fbf42b in WebCore::MediaPlayerPrivateAVFoundationObjC::currentMediaTime() const at /Volumes/Data/Users/adachan/WebKit/OpenSource/Source/WebCore/platform/graphics/avfoundation/objc/MediaPlayerPrivateAVFoundationObjC.mm:1288
#8    0x0000000111fa6ec2 in WebCore::MediaPlayer::currentTime() const at /Volumes/Data/Users/adachan/WebKit/OpenSource/Source/WebCore/platform/graphics/MediaPlayer.cpp:535
#9    0x0000000111576986 in WebCore::HTMLMediaElement::refreshCachedTime() const at /Volumes/Data/Users/adachan/WebKit/OpenSource/Source/WebCore/html/HTMLMediaElement.cpp:2584
#10    0x000000011157c2fe in WebCore::HTMLMediaElement::currentMediaTime() const at /Volumes/Data/Users/adachan/WebKit/OpenSource/Source/WebCore/html/HTMLMediaElement.cpp:2671
#11    0x0000000111581907 in WebCore::HTMLMediaElement::endedPlayback() const at /Volumes/Data/Users/adachan/WebKit/OpenSource/Source/WebCore/html/HTMLMediaElement.cpp:4586
#12    0x00000001115883ac in WebCore::HTMLMediaElement::couldPlayIfEnoughData() const at /Volumes/Data/Users/adachan/WebKit/OpenSource/Source/WebCore/html/HTMLMediaElement.cpp:4558
#13    0x000000011157d688 in WebCore::HTMLMediaElement::potentiallyPlaying() const at /Volumes/Data/Users/adachan/WebKit/OpenSource/Source/WebCore/html/HTMLMediaElement.cpp:4544
#14    0x000000011157dddf in WebCore::HTMLMediaElement::updatePlayState() at /Volumes/Data/Users/adachan/WebKit/OpenSource/Source/WebCore/html/HTMLMediaElement.cpp:4676
#15    0x0000000111581e5b in WebCore::HTMLMediaElement::playInternal() at /Volumes/Data/Users/adachan/WebKit/OpenSource/Source/WebCore/html/HTMLMediaElement.cpp:2893
#16    0x0000000111581c40 in WebCore::HTMLMediaElement::play() at /Volumes/Data/Users/adachan/WebKit/OpenSource/Source/WebCore/html/HTMLMediaElement.cpp:2839
#17    0x0000000111b0a4e1 in WebCore::jsHTMLMediaElementPrototypeFunctionPlay(JSC::ExecState*) at /Volumes/Data/Users/adachan/Build/Debug/DerivedSources/WebCore/JSHTMLMediaElement.cpp:1531

The audio I/O thread is stuck here:
#0    0x00007fff8b60e932 in semaphore_wait_trap ()
...
#7    0x00007fff9ada0423 in -[AVPlayer isExternalPlaybackActive] ()
#8    0x0000000111fc904c in WebCore::MediaPlayerPrivateAVFoundationObjC::isCurrentPlaybackTargetWireless() const at /Volumes/Data/Users/adachan/WebKit/OpenSource/Source/WebCore/platform/graphics/avfoundation/objc/MediaPlayerPrivateAVFoundationObjC.mm:2743
#9    0x0000000111fa7f8b in WebCore::MediaPlayer::isCurrentPlaybackTargetWireless() const at /Volumes/Data/Users/adachan/WebKit/OpenSource/Source/WebCore/platform/graphics/MediaPlayer.cpp:859
#10    0x000000011158dadc in WebCore::HTMLMediaElement::mediaState() const at /Volumes/Data/Users/adachan/WebKit/OpenSource/Source/WebCore/html/HTMLMediaElement.cpp:6392
#11    0x000000011158dd2c in non-virtual thunk to WebCore::HTMLMediaElement::mediaState() const at /Volumes/Data/Users/adachan/WebKit/OpenSource/Source/WebCore/html/HTMLMediaElement.cpp:6384
#12    0x000000011100b696 in WebCore::Document::updateIsPlayingMedia() at /Volumes/Data/Users/adachan/WebKit/OpenSource/Source/WebCore/dom/Document.cpp:3496
#13    0x0000000110b4bb0d in WebCore::AudioContext::isPlayingAudioDidChange() at /Volumes/Data/Users/adachan/WebKit/OpenSource/Source/WebCore/Modules/webaudio/AudioContext.cpp:1080
#14    0x0000000110b69074 in WebCore::AudioDestinationNode::updateIsEffectivelyPlayingAudio() at /Volumes/Data/Users/adachan/WebKit/OpenSource/Source/WebCore/Modules/webaudio/AudioDestinationNode.cpp:128
#15    0x0000000110b68f53 in WebCore::AudioDestinationNode::setIsSilent(bool) at /Volumes/Data/Users/adachan/WebKit/OpenSource/Source/WebCore/Modules/webaudio/AudioDestinationNode.cpp:117
#16    0x0000000110b68ecf in WebCore::AudioDestinationNode::render(WebCore::AudioBus*, WebCore::AudioBus*, unsigned long) at /Volumes/Data/Users/adachan/WebKit/OpenSource/Source/WebCore/Modules/webaudio/AudioDestinationNode.cpp:98
#17    0x0000000110b68f9f in non-virtual thunk to WebCore::AudioDestinationNode::render(WebCore::AudioBus*, WebCore::AudioBus*, unsigned long) at /Volumes/Data/Users/adachan/WebKit/OpenSource/Source/WebCore/Modules/webaudio/AudioDestinationNode.cpp:56
#18    0x0000000110b687d4 in WebCore::AudioDestinationMac::render(unsigned int, AudioBufferList*) at /Volumes/Data/Users/adachan/WebKit/OpenSource/Source/WebCore/platform/audio/mac/AudioDestinationMac.cpp:165
#19    0x0000000110b68607 in WebCore::AudioDestinationMac::inputProc(void*, unsigned int*, AudioTimeStamp const*, unsigned int, unsigned int, AudioBufferList*) at /Volumes/Data/Users/adachan/WebKit/OpenSource/Source/WebCore/platform/audio/mac/AudioDestinationMac.cpp:189
#20    0x000000012b97a0b3 in AUInputElement::PullInput(unsigned int&, AudioTimeStamp const&, unsigned int, unsigned int) ()

The audio I/O thread should never call into WebCore in a render callback, since the call into WebCore might block and we'll end up with a deadlock.  We should make sure that call is done asynchronously on the main thread.

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