"Strict" tracking protection sometimes causes _all_ content to fail to display on browser launch

[Dan Watkins]

This morning I booted my machine and launched Firefox. I restored my tabs from my previous session, and _none of them_ displayed any content. The tabs included pins, regular sites, and extension dialogs (specifically, a couple of instances of the LastPass 2FA prompt). Further to that, Firefox menus also wouldn't display; either via right-click on tabs, or via the "hamburger" menu in the top-right. (I could still close tabs via Ctrl-W for non-pinned tabs, or via middle-click for pinned tabs.)

favicons were displayed correctly, and I confirmed that the pages were actually being fetched from the remote sites because I typed the address for a page I know redirects and the redirect happened (specifically, "!g foo" in my address bar caused DuckDuckGo to redirect me to Google).

Restarting the browser did not fix this. Closing all of my tabs and restarting the browser did not fix this. Closing all of my tabs and restarting the browser, however, _did_ allow the Firefox menus to render (provided I didn't try to open any web pages before using them), which allowed me to switch "Enhanced Tracking Protection" from Strict to Standard, fixing the problem.

(This is the second time I've experienced this exact behaviour, which is how I knew to try modifying the tracking protection setting. The last time was on an older version of Firefox in August: https://wrestle.town/@Odd_Bloke/102655281770357045)

ProblemType: Bug
DistroRelease: Ubuntu 20.04
Package: firefox 72.0.2+build1-0ubuntu1
Uname: Linux 5.4.5-050405-generic x86_64
NonfreeKernelModules: nvidia_modeset nvidia
AddonCompatCheckDisabled: False
ApportVersion: 2.20.11-0ubuntu16
Architecture: amd64
BuildID: 20200117190643
Channel: Unavailable
CurrentDesktop: i3
Date: Tue Feb 4 13:01:53 2020
Extensions: extensions.sqlite corrupt or missing
ForcedLayersAccel: False
IfupdownConfig:
 # interfaces(5) file used by ifup(8) and ifdown(8)
 auto lo
 iface lo inet loopback
IncompatibleExtensions: Unavailable (corrupt or non-existant compatibility.ini or extensions.sqlite)
InstallationDate: Installed on 2019-05-07 (273 days ago)
InstallationMedia: Ubuntu 18.04.2 LTS "Bionic Beaver" - Release amd64 (20190210)
Locales: extensions.sqlite corrupt or missing
MostRecentCrashID: bp-94f8002b-6eb0-4faf-98c0-257a62150805
PrefErrors: Unexpected character ',' before close parenthesis @ /usr/lib/firefox/omni.ja:greprefs.js:724
PrefSources: prefs.js
Profiles: Profile0 (Default) - LastVersion=72.0.2/20200117190643 (In use)
RunningIncompatibleAddons: False
SourcePackage: firefox
Themes: extensions.sqlite corrupt or missing
UpgradeStatus: Upgraded to focal on 2019-11-15 (80 days ago)
dmi.bios.date: 01/25/2019
dmi.bios.vendor: American Megatrends Inc.
dmi.bios.version: F4
dmi.board.asset.tag: Default string
dmi.board.name: B450M DS3H-CF
dmi.board.vendor: Gigabyte Technology Co., Ltd.
dmi.board.version: x.x
dmi.chassis.asset.tag: Default string
dmi.chassis.type: 3
dmi.chassis.vendor: Default string
dmi.chassis.version: Default string
dmi.modalias: dmi:bvnAmericanMegatrendsInc.:bvrF4:bd01/25/2019:svnGigabyteTechnologyCo.,Ltd.:pnB450MDS3H:pvrDefaultstring:rvnGigabyteTechnologyCo.,Ltd.:rnB450MDS3H-CF:rvrx.x:cvnDefaultstring:ct3:cvrDefaultstring:
dmi.product.family: Default string
dmi.product.name: B450M DS3H
dmi.product.sku: Default string
dmi.product.version: Default string
dmi.sys.vendor: Gigabyte Technology Co., Ltd.

[Dan Watkins (oddbloke)]

Oh, an important note: I can re-enable Strict mode after switching away from it, and the browser continues to function normally.

[Dan Watkins (oddbloke)]

This just happened again (on 73.0+build3-0ubuntu1) and I've noticed that the issue appears to apply _per window_. So if I launch Firefox and this is happening, then I can open a new window and, provided I don't open any websites, the menus function correctly (to allow me to disable Strict tracking protection). Once disabled, tabs within the first window still fail to display content (until the browser is restarted), but tabs within a new window work as expected (without a restart).

[Olivier Tilloy (osomon)]

Thanks for the report Dan, and sorry for the lack of feedback so far.
This sounds like it might be an upstream bug, would you mind filing one at https://bugzilla.mozilla.org/enter_bug.cgi#h=dupes%7CFirefox and sharing the link to it here?

[Dan Watkins (oddbloke)]

User Agent: Mozilla/5.0 (X11; Ubuntu; Linux x86_64; rv:73.0) Gecko/20100101 Firefox/73.0

Steps to reproduce:

Enabled Strict tracking protection and, after several weeks of using Firefox, launched Firefox one day and the bug occurred. I have not been able to reliably reproduce it, though once in the buggy state, it reproduces on every launch.

I've experienced this on (Ubuntu's version of) 72.x and 73.x, as well as back in August on what would probably have been 68.x (but I didn't make a note).

Actual results:

No tabs would display any content. I restored my tabs, so this included pins, regular sites, and extension dialogs. Further to that, Firefox menus also wouldn't display; either via right-click on tabs, or via the "hamburger" menu in the top-right. (I could still close tabs via Ctrl-W for non-pinned tabs, or via middle-click for pinned tabs.)

favicons were displayed correctly, and I confirmed that the pages were actually being fetched from the remote sites because I typed the address for a page I know redirects and the redirect happened (specifically, "!g foo" in my address bar caused DuckDuckGo to redirect me to Google).

Restarting the browser did not fix this. Closing all of my tabs and restarting the browser did not fix this. Closing all of my tabs and restarting the browser, however, _did_ allow the Firefox menus to render (provided I didn't try to open any web pages before using them), which allowed me to switch "Enhanced Tracking Protection" from Strict to Standard, fixing the problem (on browser restart).

I also noticed that at least part of the problem appears to apply only per-window: if I opened a new window then menus would render in that window (until I opened a web page).

I have been able to re-enable Strict mode on the first launch after switching away from it, and the browser continues to function normally.

Expected results:

Firefox should have behaved as it always does, displaying site content.

[Dan Watkins (oddbloke)]

Thanks Olivier! I've filed https://bugzilla.mozilla.org/show_bug.cgi?id=1617292

[Dan Watkins (oddbloke)]

I originally reported this downstream in Ubuntu here: https://bugs.launchpad.net/ubuntu/+source/firefox/+bug/1861913

[Daniel-bodea (daniel-bodea)]

I did not manage to reproduce your issue using the provided information.
Daniel, When this issue occurs, can you check the Browser Console for errors and put them here?
Furthermore, since I do not really know what could cause this issue or how to troubleshoot it, please also go to the "about:support" page, copy and paste the information displayed about your system. Hopefully, it will help.

Thank you for your contribution!

[Dan Watkins (oddbloke)]

Created attachment 9146163
raw_data.json

I don't see any errors in the Browser Console, only a warning: "unreachable code after return statement" in "injected.js:7:2". I've copied the raw data and attached it here.

[Release-mgmt-account-bot (release-mgmt-account-bot)]

The bug has a release status flag that shows some version of Firefox is affected, thus it will be considered confirmed.