1870273 - Firefox freezes when handling tabs

Status: UNCONFIRMED

(Firefox :: Tabbed Browser, defect)

Description

[nico.venuti]

Attachment: system_info.txt

User Agent: Mozilla/5.0 (X11; Linux x86_64; rv:120.0) Gecko/20100101 Firefox/120.0

Steps to reproduce:

The issue presents itself at random when I switch between (or drag) tabs in a Firefox window.

With a normal use of the browser this random event might present itself once every 2 hours. I can cause the freeze-up in a short time by holding CTRL+TAB and dragging one tab to change their order while firefox cycles through the tabs in the open window.

Actual results:

The whole window becomes unresponsive, with the last tab I was switching from still in front. The content of the window often disappear for intervals of 1-2 seconds, then are displayed again. I can drag the window around, minimize it, I can even scroll inside it, but it is impossible to give any input in any tab. The only action somewhat possible to do inside the window is bring other tabs in front, it is still quite hard for the input to register, and if it does, the selected tab changes but the content of the window often remains frozen to the one of the old tab.
The issue goes away only I close the specific Firefox window, or if I manage to select and drag one tab out of the frozen window into its own new window. Then everything works as intended, like nothing ever happened.

While the window is frozen, the rest of the desktop is responsive as normal, even other Firefox windows. If I try to interact with the frozen window htop sometimes shows spikes of CPU usage but not often. RAM stays at normal usage levels, far from being full.

Expected results:

The browser window doesn't freeze when handling tabs.

Comment 1

[BugBot [:suhaib / :marco]]

The Bugbug bot thinks this bug should belong to the 'Firefox::Tabbed Browser' component, and is moving the bug to that component. Please correct in case you think the bot is wrong.

Comment 2

[nico.venuti]

I didn't know where to place this information in the original post:

1. The issue persist in Troubleshooting mode

2. The issue seems to not present itself if I switch nvidia driver to 390 (earliest version possible to select through my system's Driver Manager). It's impossible to say if it really doesn't exist only based on observed behaviour. I tried to trigger the issue with an effort that would ensure some 10 episodes the other drivers. I don't want to mislead people but this is what I observe.

Comment 3

[nico.venuti]

3. The issue persists with
   -a new profile

• hardware acceleration disabled
• re-newed places.* files

Comment 4

[Ciprian Georgiu, Desktop QA]

Hi, nico.venuti! Thanks for the report and the information provided. Unfortunately, I am not able to reproduce the bug using Firefox 120 on Linux Mint 21.1, the browser correctly handles the tabs when opening, dragging multiple tabs in Firefox window.

Can you please check if the issue persist with the latest Nightly 122.0a1 build?

Comment 5

[nico.venuti]

Thanks for the reply.

With the version you suggested I experience the issue in the same way.
Just to be sure: what I did was download firefox-122.0a1.en-US.linux-x86_64.tar.bz2, unpack it and run firefox-bin from that folder as is.

Other things I had not mentioned in my original post:

When I start firefox from terminal, I get these warnings:

bolometer@mintmachine:~/Downloads/firefox$ firefox
ATTENTION: default value of option mesa_glthread overridden by environment.
ATTENTION: default value of option mesa_glthread overridden by environment.
[Parent 23692, Main Thread] WARNING: Failed to call GetIdletime(): GDBus.Error:org.freedesktop.DBus.Error.ServiceUnknown: The name org.gnome.Mutter.IdleMonitor was not provided by any .service files
: 'glib warning', file /builds/worker/checkouts/gecko/toolkit/xre/nsSigHandlers.cpp:187

** (firefox:23692): WARNING **: 21:23:49.659: Failed to call GetIdletime(): GDBus.Error:org.freedesktop.DBus.Error.ServiceUnknown: The name org.gnome.Mutter.IdleMonitor was not provided by any .service files

With the 122 Nightly version I ony get the first two lines about environment variables.

I have been looking at .xsession-errors and dbus-monitor but no new lines are communicated in correspondence to the freezes.

Comment 6

[nico.venuti]

An update:
changing nglayout.enable_drag_images to false seems to be doing the trick for me.
Re-enabling it makes the issue re-appear. Maybe it makes sense, given that when you drag a tab a little ghost image appears just like when you are dragging pictures...

It has only been a few hours, I don't want to get ahead of myself. I'll see how it goes in the next few days.

Comment 7

[nico.venuti]

So, I think it's clear that this last change has fixed the freezing problem. I am not able to find the specific reason behind this unfortunately.

Comment 8

[BugBot [:suhaib / :marco]]

The severity field is not set for this bug.
:dao, could you have a look please?

For more information, please visit BugBot documentation.

Comment 9

[sebastien.bertrand.1]

Hello,

It's happening on my Ubuntu PC but not my Windows, after a profile reset I still have the problem on Ubuntu.
Maybe it's related to the graphic card?

For more info :

• the support post : https://support.mozilla.org/en-US/questions/1434065
• another related bug #1743503