1851803 - Intermittent SUMMARY: ThreadSanitizer: data race /builds/worker/checkouts/gecko/dom/media/MediaTrackGraph.cpp:2534:7 in ApplyTrackDisabling

Status: RESOLVED FIXED

(Core :: Audio/Video: MediaStreamGraph, defect, P2)

Description

[Treeherder Bug Filer]

Filed by: smolnar [at] mozilla.com
Parsed log: https://treeherder.mozilla.org/logviewer?job_id=428117688&repo=autoland
Full log: https://firefox-ci-tc.services.mozilla.com/api/queue/v1/task/Iw9E_2DRSJGmhcsNpvKz4w/runs/0/artifacts/public/logs/live_backing.log

---

TEST-START | browser/base/content/test/webrtc/browser_global_mute_toggles.js
[task 2023-09-06T11:06:28.649Z] 11:06:28     INFO - GECKO(3905) | TEST DEVICES: Using media devices:
[task 2023-09-06T11:06:28.650Z] 11:06:28     INFO - GECKO(3905) | audio:
[task 2023-09-06T11:06:28.650Z] 11:06:28     INFO - GECKO(3905) | video:
[task 2023-09-06T11:06:30.154Z] 11:06:30     INFO - GECKO(3905) | JavaScript error: resource:///actors/WebRTCChild.sys.mjs, line 502: InvalidStateError: JSWindowActorChild.sendAsyncMessage: JSWindowActorChild cannot send at the moment
[task 2023-09-06T11:06:30.596Z] 11:06:30     INFO - GECKO(3905) | TEST DEVICES: Using media devices:
[task 2023-09-06T11:06:30.596Z] 11:06:30     INFO - GECKO(3905) | audio:
[task 2023-09-06T11:06:30.596Z] 11:06:30     INFO - GECKO(3905) | video:
[task 2023-09-06T11:06:32.748Z] 11:06:32     INFO - GECKO(3905) | TEST DEVICES: Using media devices:
[task 2023-09-06T11:06:32.748Z] 11:06:32     INFO - GECKO(3905) | audio:
[task 2023-09-06T11:06:32.748Z] 11:06:32     INFO - GECKO(3905) | video:
[task 2023-09-06T11:06:35.025Z] 11:06:35     INFO - GECKO(3905) | TEST DEVICES: Using media devices:
[task 2023-09-06T11:06:35.026Z] 11:06:35     INFO - GECKO(3905) | audio:
[task 2023-09-06T11:06:35.027Z] 11:06:35     INFO - GECKO(3905) | video:
[task 2023-09-06T11:06:36.902Z] 11:06:36     INFO - GECKO(3905) | ==================
[task 2023-09-06T11:06:36.903Z] 11:06:36     INFO - GECKO(3905) | WARNING: ThreadSanitizer: data race (pid=5680)
[task 2023-09-06T11:06:36.903Z] 11:06:36     INFO - GECKO(3905) |   Read of size 4 at 0x7b3800010b40 by thread T22 (mutexes: write M0):
[task 2023-09-06T11:06:36.906Z] 11:06:36     INFO - GECKO(3905) |     #0 ApplyTrackDisabling /builds/worker/checkouts/gecko/dom/media/MediaTrackGraph.cpp:2534:7 (libxul.so+0x7281000) (BuildId: aae31bb572c22f6aa66ee2385764143c7a55f690)
<...>
#41 main /builds/worker/checkouts/gecko/browser/app/nsBrowserApp.cpp:375:18 (firefox-bin+0x134b01)
[task 2023-09-06T11:06:37.189Z] 11:06:37     INFO - GECKO(3905) | SUMMARY: ThreadSanitizer: data race /builds/worker/checkouts/gecko/dom/media/MediaTrackGraph.cpp:2534:7 in ApplyTrackDisabling
[task 2023-09-06T11:06:37.189Z] 11:06:37     INFO - GECKO(3905) | ==================
[task 2023-09-06T11:06:37.190Z] 11:06:37     INFO - GECKO(3905) | console.error:
[task 2023-09-06T11:06:37.191Z] 11:06:37     INFO - GECKO(3905) |   remote browser crashed while on
[task 2023-09-06T11:06:37.191Z] 11:06:37     INFO - GECKO(3905) |   https://example.com/browser/browser/base/content/test/webrtc/get_user_media.html
[task 2023-09-06T11:06:37.192Z] 11:06:37     INFO - TEST-INFO | started process screentopng
[task 2023-09-06T11:06:37.217Z] 11:06:37     INFO - TEST-INFO | screentopng: exit 0
[task 2023-09-06T11:06:37.217Z] 11:06:37     INFO - <snipped 10 output lines - if you need more context, please use SimpleTest.requestCompleteLog() in your test>
[task 2023-09-06T11:06:37.217Z] 11:06:37     INFO - Buffered messages logged at 11:06:29
[task 2023-09-06T11:06:37.217Z] 11:06:37     INFO - TEST-PASS | browser/base/content/test/webrtc/browser_global_mute_toggles.js | Camera selector label should not be hidden. - 

Comment 1

[Andrew McCreight [:mccr8]]

Attachment: full TSan report

Comment 2

[Andrew McCreight [:mccr8]]

Here's a few frames from the TSan report:

Read of size 4 at 0x7b3800010b40 by thread T22 (mutexes: write M0):
#0 ApplyTrackDisabling /builds/worker/checkouts/gecko/dom/media/MediaTrackGraph.cpp:2534:7
#1 mozilla::SourceMediaTrack::ApplyTrackDisabling(mozilla::MediaSegment*, mozilla::MediaSegment*) /builds/worker/checkouts/gecko/dom/media/MediaTrackGraph.h:664:17
#2 mozilla::SourceMediaTrack::AppendData(mozilla::MediaSegment*, mozilla::MediaSegment*) /builds/worker/checkouts/gecko/dom/media/MediaTrackGraph.cpp:2869:3
#3 mozilla::MediaEngineFakeVideoSource::GenerateFrame() /builds/worker/checkouts/gecko/dom/media/webrtc/MediaEngineFake.cpp:410:11

Previous write of size 4 at 0x7b3800010b40 by thread T25 (mutexes: write M1):
#0 SetDisabledTrackModeImpl /builds/worker/checkouts/gecko/dom/media/MediaTrackGraph.cpp:2511:17
#1 mozilla::SourceMediaTrack::SetDisabledTrackModeImpl(mozilla::DisabledTrackMode) /builds/worker/checkouts/gecko/dom/media/MediaTrackGraph.cpp:3029:15
#2 mozilla::MediaTrack::SetDisabledTrackMode(mozilla::DisabledTrackMode)::Message::Run() /builds/worker/checkouts/gecko/dom/media/MediaTrackGraph.cpp:2522:15
#3 mozilla::MediaTrackGraphImpl::RunMessagesInQueue() /builds/worker/checkouts/gecko/dom/media/MediaTrackGraph.cpp:1292:20

Comment 3

[Andrew McCreight [:mccr8]]

It looks like this is a race on MediaTrack::mDisabledMode. This doesn't seem super dangerous so I'll mark it sec-moderate.

Comment 4

[Andreas Pehrson [:pehrsons]]

Ah, thanks, well that is a trivial fix.

Comment 5

[Andreas Pehrson [:pehrsons]]

This is an old regression. I can't find a motivation for it in the bug, unfortunately. But a quick audit at least doesn't render any path that would deadlock -- there are some callbacks that would be called under the SourceMediaTrack mutex.

Comment 6

[Andreas Pehrson [:pehrsons]]

Attachment: Bug 1851803 - Introduce SourceMediaTrack::mDirectDisabledMode. r?karlt!

Comment 7

[BugBot [:suhaib / :marco/ :calixte]]

Set release status flags based on info from the regressing bug 1266644

Comment 8

[Karl Tomlinson (:karlt)]

See the duplicate bug 1701452 comment 3 for analysis.

Comment 9

[Pulsebot]

Pushed by [e-mail]:
https://hg.mozilla.org/integration/autoland/rev/589b8056178b
Introduce SourceMediaTrack::mDirectDisabledMode. r=karlt

Comment 11

[Sebastian Hengst [:aryx] (needinfo me if it's about an intermittent or backout)]

https://hg.mozilla.org/mozilla-central/rev/589b8056178b

Comment 12

[BugBot [:suhaib / :marco/ :calixte]]

The patch landed in nightly and beta is affected.
:pehrsons, is this bug important enough to require an uplift?

• If yes, please nominate the patch for beta approval.
• If no, please set status-firefox118 to wontfix.

For more information, please visit BugBot documentation.

Comment 13

[Andreas Pehrson [:pehrsons]]

This is pretty harmless.

Comment 14

[Daniel Veditz [:dveditz]]

Bulk-unhiding security bugs fixed in Firefox 119-121 (Fall 2023). Use "moo-doctrine-subsidy" to filter