1145787 - B2G: F/MOZ_Assert( 210): Assertion failure: mFrameMetrics.IsRootScrollable(), at ../../../gecko/gfx/layers/apz/src/AsyncPanZoomController.cpp:1291

Status: RESOLVED FIXED

(Core :: Panning and Zooming, defect)

Description

[No-Jun Park [:njpark]]

STR: 
Load the debug build
in the browser app, go to http://cnn.it/1H9l370
scroll up/down, and pinch zoom in/out
The browser will crash, and the logcat shows following assertion at the time of the crash: 

F/MOZ_Assert(  210): Assertion failure: mFrameMetrics.IsRootScrollable(), at ../../../gecko/gfx/layers/apz/src/AsyncPanZoomController.cpp:1291


Also, while scrolling the webpage, below assertion failure is shown periodically:

I/Gecko   (12788): [Child 12788] ###!!! ASSERTION: old rule tree still referenced: 'Not Reached', file ../../../gecko/layout/style/nsStyleSet.cpp, line 2124

Version Info:
Gaia-Rev        8837f94418d69a0b06c1f4843b0779e2bb72165a
Gecko-Rev       https://hg.mozilla.org/integration/mozilla-inbound/rev/d74279a9b861
Build-ID        20150320073136
Version         39.0a1
Device-Name     flame
FW-Release      4.4.2
FW-Incremental  eng.cltbld.20150320.110113
FW-Date         Fri Mar 20 11:01:24 EDT 2015
Bootloader      L1TC000118D0

Comment 1

[Botond Ballo [:botond]]

This assertion was added in bug 1036967.

Comment 2

[Botond Ballo [:botond]]

Silly me. I intended for this assertion to check that OnScale() is only called on the root (in the IsRootScrollable() sense) APZC, but I added it before the 'mState != PINCHING' check.

Turns out the mechanism we use to prevent non-root APZCs from being zoomed is by not allowing them to get into the PINCHING state - they can safely get into OnScale(), which exits at that check.

Comment 3

[Botond Ballo [:botond]]

Attachment: MozReview Request: bz://1145787/botond

/r/5813 - Bug 1145787 - Put a misplaced assertion into its proper place. r=kats

Pull down this commit:

hg pull review -r 07e2f4f06c86222b3f8064bac43cab4fe47a96bc

Comment 4

[Kartikaya Gupta (email:[e-mail])]

IIRC only the root APZC for a process should be receiving the touch events with more than one touch, and so only the root APZC should be getting OnScaleBegin/OnScale calls. It sounds like that's not the case?

Comment 5

[Botond Ballo [:botond]]

(In reply to Kartikaya Gupta (email:[e-mail]) from comment #4)
> IIRC only the root APZC for a process should be receiving the touch events
> with more than one touch, and so only the root APZC should be getting
> OnScaleBegin/OnScale calls. It sounds like that's not the case?

The root APZC in the root process is not IsRootScrollable() (and cannot be zoomed).

Comment 6

[Kartikaya Gupta (email:[e-mail])]

Comment on attachment 8580978 [details]
MozReview Request: bz://1145787/botond

https://reviewboard.mozilla.org/r/5811/#review4797

Ship It!

Comment 7

[Botond Ballo [:botond]]

Try push that includes this patch: https://treeherder.mozilla.org/#/jobs?repo=try&revision=a430e26d1578

Comment 9

[Botond Ballo [:botond]]

https://hg.mozilla.org/integration/mozilla-inbound/rev/a7e0ef41f518

Comment 10

[Ryan VanderMeulen [:RyanVM]]

https://hg.mozilla.org/mozilla-central/rev/a7e0ef41f518

Comment 12

[Botond Ballo [:botond]]

Attachment: MozReview Request: Bug 1145787 - Put a misplaced assertion into its proper place. r=kats