1809860 - Crash in [@ mozilla::Maybe<T>::emplace<T> | webrtc::videocapturemodule::VideoCaptureAvFoundation::SetTrackingId]

Status: VERIFIED FIXED

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

Description

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

3 crashes from 2 installations, both macOS Firefox 110.0a1 20230111215657

Crash report: https://crash-stats.mozilla.org/report/index/3e179612-82a1-40aa-9dfa-3234d0230112

MOZ_CRASH Reason: MOZ_RELEASE_ASSERT(!isSome())

Top 10 frames of crashing thread:

0  XUL  mozilla::Maybe<mozilla::TrackingId>::emplace<mozilla::TrackingId::Source, unsigned int&>  mfbt/Maybe.h:844
0  XUL  webrtc::videocapturemodule::VideoCaptureAvFoundation::SetTrackingId  dom/media/systemservices/objc_video_capture/video_capture_avfoundation.mm:235
1  XUL  mozilla::camera::CamerasParent::RecvStartCapture const  dom/media/systemservices/CamerasParent.cpp:941
1  XUL  std::__1::__invoke<mozilla::camera::CamerasParent::RecvStartCapture  /builds/worker/fetches/MacOSX11.3.sdk/usr/include/c++/v1/type_traits:3747
1  XUL  std::__1::__invoke_void_return_wrapper<void>::__call<mozilla::camera::CamerasParent::RecvStartCapture  /builds/worker/fetches/MacOSX11.3.sdk/usr/include/c++/v1/__functional_base:348
1  XUL  std::__1::__function::__alloc_func<mozilla::camera::CamerasParent::RecvStartCapture  /builds/worker/fetches/MacOSX11.3.sdk/usr/include/c++/v1/functional:1553
1  XUL  std::__1::__function::__func<mozilla::camera::CamerasParent::RecvStartCapture  /builds/worker/fetches/MacOSX11.3.sdk/usr/include/c++/v1/functional:1727
2  XUL  std::__1::__function::__value_func<void  const  /builds/worker/fetches/MacOSX11.3.sdk/usr/include/c++/v1/functional:1880
2  XUL  std::__1::function<void  const  /builds/worker/fetches/MacOSX11.3.sdk/usr/include/c++/v1/functional:2555
2  XUL  mozilla::camera::VideoEngine::WithEntry  dom/media/systemservices/VideoEngine.cpp:242

Comment 1

[Jan-Ivar Bruaroey [:jib] (needinfo? me)]

Firefox crashes now if you open camera from two tabs at once. I vote we back out bug 1806605 before Monday. This seems bad even for Nightly.

STR:

1. Open https://jan-ivar.github.io/dummy/gum_video.html in two tabs, allowing camera in both.

Entire Firefox browser crashes (NOT merely a tab crash).

Comment 3

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

Copying crash signatures from duplicate bugs.

Comment 4

[Frederik Braun [:freddy]]

(In reply to Jan-Ivar Bruaroey [:jib] (needinfo? me) from comment #1)

Firefox crashes now if you open camera from two tabs at once. I vote we back out bug 1806605 before Monday. This seems bad even for Nightly.

If it helps, I experienced this by merely switching devices (camer/mic) on a WebRTC call on e.g., https://whereby.com/

Comment 5

[Andreas Pehrson [:pehrsons]]

That was a bad assumption. But a simple fix.

Comment 6

[Andreas Pehrson [:pehrsons]]

Attachment: Bug 1809860 - In VideoCaptureAvFoundation account for backends being sharable. r?padenot!

This is a stop-gap fix to handle camera backends being shared across multiple
camera requests. We'll have to follow up with some markers so that the analyzer
extension can understand which tracking ids are sharing which backend.

Comment 7

[Pulsebot]

Pushed by [e-mail]:
https://hg.mozilla.org/integration/autoland/rev/39508d8be196
In VideoCaptureAvFoundation account for backends being sharable. r=padenot

Comment 8

[Natalia Csoregi [:nataliaCs]]

https://hg.mozilla.org/mozilla-central/rev/39508d8be196

Comment 9

[Ciprian Georgiu, Desktop QA]

I have reproduced this crash using the test page from comment 1, with an affected Nightly build (2023-01-12). Tested with macOS 11.

The issue is verified as fixed on latest Beta 110.0b3 under macOS 11.