1708966 - Firefox freezes when reloading about:support page

Status: RESOLVED WORKSFORME

(Core :: Audio/Video: cubeb, defect, P3)

Description

[Marcel]

User Agent: Mozilla/5.0 (X11; Linux x86_64; rv:78.0) Gecko/20100101 Firefox/78.0

Steps to reproduce:

I am using Fedora 34 (but tested on Mozilla's builds).
Reproducible on 88.0 and current 90.0 Nightly with X11, Xwayland and "pure" Wayland.

1. Go to the about:support page
2. Press F5 (or the reload button)

Actual results:

The whole Firefox freezes.
Sometimes it unfreezes after seconds and sometimes killing the process is needed.

Expected results:

Firefox should at least let me switch tabs while that page reloads.

Comment 1

[BugBot [:suhaib / :marco]]

The Bugbug bot thinks this bug should belong to the 'Core::Widget: Gtk' component, and is moving the bug to that component. Please revert this change in case you think the bot is wrong.

Comment 2

[Marcel]

Attachment: about:support on Wayland

Comment 3

[Emilio Cobos Álvarez [:emilio]]

Can you try to get a profile of this? I wonder if some of the graphics diagnostics about:support runs are taking unexpectedly long.

Comment 4

[Marcel]

Yes, I could. Thanks you for looking into this :)
https://share.firefox.dev/2RopLyd

Comment 5

[Emilio Cobos Álvarez [:emilio]]

(In reply to Marcel from comment #4)

Yes, I could. Thanks you for looking into this :)
https://share.firefox.dev/2RopLyd

Wow, that's a ~30 second hang in cubeb_backend::capi::capi_get_max_channel_count. Seems it's probably some sort of timeout or something somewhere? It should probably never block the main thread though... Matthew, do you know what might be going on?

Comment 6

[Matthew Gregan [:kinetik]]

I think I can repro this, will investigate further.

Comment 7

[Marcel]

Just posting as a small update:
I am using Fedora 36 now and it doesn't happen to me anymore, not even with Firefox 88.0.
So I guess that bug was fixed by an update of a Fedora package(?).
I' ll leave this open, as I don't know if you still want to refactor the code that was involved on Firefox's side.