1735588 - Permafailing macOS "Assertion failure: NS_IsMainThread(), at /builds/worker/checkouts/gecko/gfx/thebes/gfxFontEntry.cpp:131" when shared font list is disabled

Status: RESOLVED FIXED

(Core :: Graphics: Text, defect)

Description

[Treeherder Bug Filer]

Filed by: rvandermeulen [at] mozilla.com
Parsed log: https://treeherder.mozilla.org/logviewer?job_id=354663574&repo=mozilla-esr91
Full log: https://firefox-ci-tc.services.mozilla.com/api/queue/v1/task/I7TYPMwyTJ6mbGuXNiRcyg/runs/0/artifacts/public/logs/live_backing.log

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Seen after preffing off shared font list on ESR91.

Comment 1

[Jonathan Kew [:jfkthame]]

The InitFontList thread is only safe when the shared font list is enabled; the legacy font objects are main-thread-only, so when the shared list is preffed off we should not attempt to move the initialization off to another thread.

Comment 2

[Jonathan Kew [:jfkthame]]

Attachment: Bug 1735588 - Only allow the OMT InitFontList thread to be used if the shared font list is enabled. r=lsalzman

Comment 3

[Ryan VanderMeulen [:RyanVM]]

Landed a patch on ESR91 to make gfx.font-list-omt.enabled unconditionally false there to fix the failures. Jonathan's going to write a more generic patch for this too which can land on all trees.
https://hg.mozilla.org/releases/mozilla-esr91/rev/c6f05ffc58100f4b85a11d340a3f23ba5e35dce8

Comment 4

[Intermittent Failures Robot]

62 failures in 578 pushes (0.107 failures/push) were associated with this bug yesterday.

Repository breakdown:

• mozilla-esr91: 62

Platform and build breakdown:

• macosx1015-64-qr: 62
  • debug: 62

For more details, see:
https://treeherder.mozilla.org/intermittent-failures/bugdetails?bug=1735588&startday=2021-10-13&endday=2021-10-13&tree=all

Comment 5

[Intermittent Failures Robot]

62 failures in 3315 pushes (0.019 failures/push) were associated with this bug in the last 7 days.

This is the #14 most frequent failure this week.

** This failure happened more than 30 times this week! Resolving this bug is a high priority. **

** Try to resolve this bug as soon as possible. If unresolved for 2 weeks, the affected test(s) may be disabled. **

Repository breakdown:

• mozilla-esr91: 62

Platform and build breakdown:

• macosx1015-64-qr: 62
  • debug: 62

For more details, see:
https://treeherder.mozilla.org/intermittent-failures/bugdetails?bug=1735588&startday=2021-10-11&endday=2021-10-17&tree=all

Comment 6

[Ryan VanderMeulen [:RyanVM]]

No need to track this for ESR91 anymore given comment 3.

Comment 7

[Pulsebot]

Pushed by [e-mail]:
https://hg.mozilla.org/integration/autoland/rev/fa35ddf21ee6
Only allow the OMT InitFontList thread to be used if the shared font list is enabled. r=lsalzman

Comment 8

[Norisz Fay [:noriszfay]]

https://hg.mozilla.org/mozilla-central/rev/fa35ddf21ee6

Comment 9

[Ryan VanderMeulen [:RyanVM]]

Did you want to uplift this to ESR91 for completeness' sake?

Comment 10

[Jonathan Kew [:jfkthame]]

I guess it'd make sense. With the default prefs we're shipping, it's harmless/irrelevant, but it potentially makes things more robust for people who try tweaking their prefs. And as patches go, it's about as safe as they come. :)

Comment 11

[Jonathan Kew [:jfkthame]]

Comment on attachment 9245753 [details]
Bug 1735588 - Only allow the OMT InitFontList thread to be used if the shared font list is enabled. r=lsalzman

ESR Uplift Approval Request

• If this is not a sec:{high,crit} bug, please state case for ESR consideration: This is irrelevant for users with the defaults we ship, but makes things more robust for anyone who starts tweaking their font-list prefs.
• User impact if declined: Possible thread-safety issues if users adjust prefs.
• Fix Landed on Version: 95
• Risk to taking this patch: Low
• Why is the change risky/not risky? (and alternatives if risky): Just adds a simple pref-check to avoid using an unsupported mix of features.
• String or UUID changes made by this patch:

Comment 12

[Ryan VanderMeulen [:RyanVM]]

Comment on attachment 9245753 [details]
Bug 1735588 - Only allow the OMT InitFontList thread to be used if the shared font list is enabled. r=lsalzman

Approved for 91.4esr.

Comment 13

[Ryan VanderMeulen [:RyanVM]]

https://hg.mozilla.org/releases/mozilla-esr91/rev/a35d51fc4e7d