1534238 - GraphRunner::Run can run before its constructor is finished

Status: RESOLVED FIXED

(Core :: Audio/Video: MediaStreamGraph, defect, P1)

Description

[Andreas Pehrson [:pehrsons]]

When this happens, mShutdown is uninitialized so GraphRunner::mThread runs to completion and exits, leaving any subsequent call to GraphRunner::OneIteration hanging.

Comment 1

[Andreas Pehrson [:pehrsons]]

Hmm, the symptoms here are actually a bit different, because I diagnosed this with a local patch to change [1] to say while (!mShutdown) {.

Instead the symptom on m-c should be that mStarted is set to true by GraphRunner::Run, then to false by the ctor, leaving both GraphRunner::OneIteration and GraphRunner::Run hanging.

[1] https://searchfox.org/mozilla-central/rev/2f1020dc4176d38dd5f3d0496f3c46849862ee0b/dom/media/GraphRunner.cpp#89

Comment 2

[Andreas Pehrson [:pehrsons]]

Attachment: Bug 1534238 - Initialize GraphRunner::mThread last. r?padenot

The thread may pre-empt the thread running the ctor and launch GraphRunner::Run
with uninitialized members. This patch ensures they are initialized first.

Comment 3

[Pulsebot]

Pushed by [e-mail]:
https://hg.mozilla.org/integration/autoland/rev/b015322cb779
Initialize GraphRunner::mThread last. r=padenot

Comment 4

[Bogdan Tara[:bogdan_tara | bogdant]]

https://hg.mozilla.org/mozilla-central/rev/b015322cb779