802376 - crash in mozilla::GetUserMediaRunnable::Run when selecting an integrated web cam in video and audio gum call with USB webcam, integrated webcam, and integrated mic on machine

Status: VERIFIED FIXED

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

Description

[Jason Smith [:jsmith]]

Attachment: Testcase

This bug was filed from the Socorro interface and is 
report bp-b75138ae-c5cb-404c-a03f-1a6232121016 .
============================================================= 

Steps:

1. Go to the attached test page with an integrated mic, integrated camera, and USB camera on your machine
2. When the prompt appears, select the integrated camera

Expected:

The video stream should be shown from my integrated camera. Also, if I generate sound into my integrated mic, I should hear it back through my speakers.

Actual:

Firefox crashes. This appears to be 100% reproducible too.

Comment 1

[Jason Smith [:jsmith]]

Apparently this also happens if I request audio, then request audio and video in another tab.

Comment 2

[Jason Smith [:jsmith]]

Currently in it's existing state its not crashtest worthy.

Comment 3

[Henrik Skupin [:whimboo][⌚️UTC+1]]

Are we able to simulate different devices via faked media devices? I assume not, or Randell?

Comment 4

[Randell Jesup [:jesup] (needinfo me)]

WFM, marking qawanted for restest.

We can simulate multiple fake streams

Comment 5

[Jason Smith [:jsmith]]

Still reproduces for me on 11/16 build.

https://crash-stats.mozilla.com/report/index/72e9b9d3-a1b0-42d5-89ba-e2ca52121116
https://crash-stats.mozilla.com/report/index/6f8c99da-7c6c-4f1a-8cf2-072a62121116

Comment 6

[Randell Jesup [:jesup] (needinfo me)]

Attachment: wallpaper permissions bug when selecting a camera+audio other than the first

This is only don't-crash wallpaper; you still end up with no audio.  The actual bug is in the permissions handling.  We'll want to leave-open this bug for a real fix.

Comment 7

[Randell Jesup [:jesup] (needinfo me)]

Comment on attachment 682970 [details] [diff] [review]
wallpaper permissions bug when selecting a camera+audio other than the first

Anant agrees the bug is in the permissions interface and/or API to MediaManager:

2 days ago	jesup:What audio goes with each camera in the "i want both" case is not well-defined - and the current UI doesn't show you
2 days ago	anant:jesup: are you running the same test case that's on the bug?
2 days ago	jesup:anant: it *should* select an integrated mic for each camera if they have it, and generic default mic if they don't or we can't tell
2 days ago	jesup:anant: yes
2 days ago	jesup:Select second camera, boom

2 days ago	jesup:anant: I'm right. Breaking in the ::Observe, it has type == "video", so it sets video and leaves audio null
2 days ago	jesup:and resubmits itself to call ::Run
2 days ago	jesup:I think it needs two device pointers instead of a type and a device pointer

2 days ago	anant:jesup: you're right
2 days ago	anant:it's a UI bug then

This should keep us from crashing (null deref) while we find the right fix - and it's good safety code anyways.  We could MOZ_ASSERT and do the check, but I'd rather worry about landing that with the main fix.

Comment 8

[Eric Rescorla (:ekr)]

Comment on attachment 682970 [details] [diff] [review]
wallpaper permissions bug when selecting a camera+audio other than the first

Review of attachment 682970 [details] [diff] [review]:
-----------------------------------------------------------------

lgtm

Comment 9

[Jason Smith [:jsmith]]

cc-ing the Firefox front-end folks to notify them there's a deterministic crash that could be in their arena

Comment 10

[Randell Jesup [:jesup] (needinfo me)]

https://hg.mozilla.org/integration/mozilla-inbound/rev/94669ff1101c

[leave-open]

Comment 11

[Ed Morley [:emorley]]

https://hg.mozilla.org/mozilla-central/rev/94669ff1101c

Comment 12

[Randell Jesup [:jesup] (needinfo me)]

remaining issue here is bug 802421 (and bug 823453) which refactor the permissions for multiple streams

Comment 13

[Jason Smith [:jsmith]]

Verified with a few different combinations of multiple cameras & mics - no crashes seen. 1/29 build.