848812 - ###!!! ASSERTION: Should be on state machine thread or the decoder thread.: 'OnStateMachineThread() || OnDecodeThread()',

Status: RESOLVED FIXED

(Core :: Audio/Video, defect)

Description

[Paul Adenot (:padenot)]

Here: http://mxr.mozilla.org/mozilla-central/source/content/media/MediaDecoderStateMachine.cpp#1271

This happens with this stack:

http://pastebin.mozilla.org/2200840

I think we can just remove the assert (the sister method StartPlayback does not assert). I checked what it does below, it should be fine.

Comment 1

[Matthew Gregan [:kinetik]]

Attachment: bug848812_v0.patch

Ran into this while debugging another test issue.  Analysis below:

Called on the main thread:

(gdb) bt
#0  mozilla::MediaDecoderStateMachine::StopPlayback
#1  mozilla::MediaDecoderStateMachine::StartBuffering
#2  mozilla::MediaDecoder::Resume
#3  mozilla::dom::HTMLMediaElement::Play
#4  mozilla::dom::HTMLMediaElementBinding::play

MediaDecoder::Resume acquires monitor.  MediaDecoderStateMachine::StartBuffering asserts monitor is held.  MediaDecoderStateMachine::StopPlayback also asserts monitor is held.

This looks safe to me with the monitor held, so I agree with Paul.

Comment 2

[Matthew Gregan [:kinetik]]

https://hg.mozilla.org/integration/mozilla-inbound/rev/89436074858c

Comment 3

[Carsten Book [:Tomcat]]

https://hg.mozilla.org/mozilla-central/rev/89436074858c