1314045 - Stylo debug crash in layout/reftests/font-inflation/list-1.html: "ASSERTION: Bad loading table"

Status: RESOLVED FIXED

(Core :: Layout, defect, P3)

Description

[Matt Brubeck (:mbrubeck)]

This happens when running "layout/reftests/font-inflation/list-1.html" in a Stylo debug build:

[8633] ###!!! ASSERTION: Bad loading table: 'mSheets->mLoadingDatas.Get(&key, &loadingData) && loadingData == aLoadData', file /home/mbrubeck/src/mozilla-central/layout/style/Loader.cpp, line 1879
#01: mozilla::css::Loader::DoSheetComplete(mozilla::css::SheetLoadData*, nsresult, nsTArray<RefPtr<mozilla::css::SheetLoadData> >&) (/home/mbrubeck/src/mozilla-central/layout/style/Loader.cpp:1877 (discriminator 7))
#02: mozilla::css::Loader::SheetComplete(mozilla::css::SheetLoadData*, nsresult) (/home/mbrubeck/src/mozilla-central/layout/style/Loader.cpp:1825)
#03: mozilla::css::SheetLoadData::OnStreamComplete(nsIUnicharStreamLoader*, nsISupports*, nsresult, nsAString_internal const&) (/home/mbrubeck/src/mozilla-central/layout/style/Loader.cpp:878)

This is triggered by this incorrect line in the reftest, which links to a non-existent "ahem.css":

<link rel="stylesheet" type="text/css" href="ahem.css" />

The underlying bug is that Loader::LoadSheet is called twice for the same URI, but the second call does not "glom on" to the existing load because the relevant check is in a Gecko-only code path.  As a result, the SheetLoadData inserted into Loader::mLoadingDatas by the first load is overwritten by the second load, leaving the table in an inconsistent state.

This will be fixed when caching is implemented for ServoStyleSheets, but there may be a simpler fix in the meantime.

This was originally found in bug 1292275 but it is separate from the non-debug crash fixed in that bug.

Comment 1

[Pulsebot]

Pushed by [e-mail]:
https://hg.mozilla.org/integration/mozilla-inbound/rev/4787d54f7aa6
stylo: Downgrade "Bad loading table" assertion since it occurs frequently. r=me

Comment 2

[Pulsebot]

Pushed by [e-mail]:
https://hg.mozilla.org/integration/mozilla-inbound/rev/0d069e7395e9
stylo: Downgrade "Bad loading table" assertion since it occurs frequently. r=me

Comment 3

[Pulsebot]

Backout by [e-mail]:
https://hg.mozilla.org/integration/mozilla-inbound/rev/959f53ed7fad
Backed out changeset 4787d54f7aa6

Comment 4

[Sebastian Hengst [:aryx] (needinfo me if it's about an intermittent or backout)]

Backed out for Windows debug build bustage:

https://hg.mozilla.org/integration/mozilla-inbound/rev/70e19926d22bc7ad68fc64825a869ab65afde184

Re-push with failures: https://treeherder.mozilla.org/#/jobs?repo=mozilla-inbound&revision=a59eac65cc60b1c926d3d4fd8051c7b6e308b076
Failure log: https://treeherder.mozilla.org/logviewer.html#?job_id=73304124&repo=mozilla-inbound

> c:/builds/moz2_slave/m-in-w32-d-0000000000000000000/build/src/layout/style/Loader.cpp(1885): error C2220: warning treated as error - no 'object' file generated

Comment 5

[Pulsebot]

Pushed by [e-mail]:
https://hg.mozilla.org/integration/mozilla-inbound/rev/89782a895ca2
stylo: Downgrade "Bad loading table" assertion since it occurs frequently. r=me

Comment 6

[Carsten Book [:Tomcat]]

https://hg.mozilla.org/mozilla-central/rev/89782a895ca2

Comment 8

[Brad Werth [:bradwerth]]

I'll take this on.

Comment 9

[Brad Werth [:bradwerth]]

Attachment: Bug 1314045 Part 1: Return load table assertion to full force now that Servo stylesheet caching will keep load table consistent.

Review commit: https://reviewboard.mozilla.org/r/119304/diff/#index_header
See other reviews: https://reviewboard.mozilla.org/r/119304/

Comment 10

[Cameron McCormack (:heycam)]

Comment on attachment 8846202 [details]
Bug 1314045 Part 1: Return load table assertion to full force now that Servo stylesheet caching will keep load table consistent.

https://reviewboard.mozilla.org/r/119304/#review121296

Comment 11

[Pulsebot]

Pushed by [e-mail]:
https://hg.mozilla.org/integration/autoland/rev/13e7021f1350
Part 1: Return load table assertion to full force now that Servo stylesheet caching will keep load table consistent. r=heycam

Comment 12

[Wes Kocher (:KWierso) (Not reading bugmail; email directly if needed)]

https://hg.mozilla.org/mozilla-central/rev/13e7021f1350