1002325 - crash in nsPresContext::RebuildUserFontSet()

Status: VERIFIED FIXED

(Core :: Graphics: Text, defect)

Description

[(Away)]

This bug was filed from the Socorro interface and is 
report bp-71c75c57-0b82-46c4-833c-19bf52140420.
=============================================================

New crash on nightly starting 18th April. null nsPresContext here:

xul!nsPresContext::RebuildUserFontSet
xul!nsUserFontSet::DoRebuildUserFontSet
xul!gfxUserFontSet::RebuildLocalRules
xul!RebuildLocalFonts
xul!nsTHashtable<nsUint64HashKey>::s_EnumStub
xul!PL_DHashTableEnumerate
xul!nsTHashtable<nsPtrHashKey<gfxUserFontSet> >::EnumerateEntries
xul!gfxPlatformFontList::UpdateFontList
xul!gfxWindowsPlatform::UpdateFontList
xul!nsThebesFontEnumerator::UpdateFontList
xul!nsWindow::ProcessMessage

This code was added in bug 964613.

Comment 1

[Jonathan Kew [:jfkthame]]

Attachment: don't try to rebuild rules if the font set is being deleted.

Looks like a simple null-check should be sufficient here. mPresContext should never be null -except- when the font set is destined for deletion, in which case we no longer care about rebuilding rules.

Comment 2

[Jonathan Kew [:jfkthame]]

https://hg.mozilla.org/integration/mozilla-inbound/rev/293ecda82136

I suggest we leave this bug open until we've had a few days on Nightly to confirm that the crashes go away.

Comment 3

[Ed Morley [:emorley]]

https://hg.mozilla.org/mozilla-central/rev/293ecda82136

Comment 4

[(Away)]

No crashes on nightly since the 5/1 build.

Comment 5

[Jonathan Kew [:jfkthame]]

Comment on attachment 8413613 [details] [diff] [review]
don't try to rebuild rules if the font set is being deleted.

[Approval Request Comment]
Bug caused by (feature/regressing bug #): 964613
User impact if declined: sporadic crashiness on pages that use webfonts
Testing completed (on m-c, etc.): several days on nightly since patch landed, no crash reports seen
Risk to taking this patch (and alternatives if risky): minimal risk
String or IDL/UUID changes made by this patch: none

Comment 6

[Jonathan Kew [:jfkthame]]

(In reply to David Major [:dmajor] (UTC+12) from comment #4)
> No crashes on nightly since the 5/1 build.

Thanks for following up; marking this fixed on trunk.

Comment 7

[Jonathan Kew [:jfkthame]]

https://hg.mozilla.org/releases/mozilla-aurora/rev/2056d140b1bf

Comment 8

[Paul Silaghi, QA [:pauly]]

(In reply to David Major [:dmajor] (UTC+12) from comment #4)
> No crashes on nightly since the 5/1 build.
Confirmed

Comment 9

[Liz Henry (:lizzard) (relman/hg->git project)]

No crashes after the 20140505004003 build for 31.