1375843 - Lots and lots of "WARN:webrender::clip_scroll_node: Tried to scroll a non-scroll node." in automation

Status: RESOLVED FIXED

(Core :: Graphics: WebRender, defect, P3)

Description

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

There are recent spikes in bug 1206887 and bug 1204281 on linux64-qr. If you look at the logs you'll see reams and reams of this warning:

  WARN:webrender::clip_scroll_node: Tried to scroll a non-scroll node.

Seems like a bug. Note that is a regression from enabling APZ on webrender, but it might be triggered by other factors (that seems to be the case for bug 1204281 at least).

Comment 1

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

I reproduced this locally. The warning that's getting hit is the one at [1]. The clip_id at the call site [2] is something like DynamicallyAddedNode(1, PipelineId(1, 1)) which is something we never try to set a scroll offset on from the gecko side. So this is probably something that needs to be fixed internally in webrender. For now I can silence the warning since it seems to be benign (other than causing timeouts in automation).

[1] http://searchfox.org/mozilla-central/rev/ae94cfb36d804727dfb38f2750bfcaab4621df6e/gfx/webrender/src/clip_scroll_node.rs#196
[2] http://searchfox.org/mozilla-central/rev/ae94cfb36d804727dfb38f2750bfcaab4621df6e/gfx/webrender/src/clip_scroll_tree.rs#310

Comment 2

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

For posterity, I reproduced this by doing a mozilla-central opt build, replacing the warn! line with println! so that it would get printed unconditionally. Then I just ran |MOZ_WEBRENDER=1 mach reftest layout/reftests/reftest-sanity| and saw the spew.

Comment 3

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

Filed https://github.com/servo/webrender/issues/1424 for the issue in upstream.

Comment 4

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

Attachment: Bug 1375843 - Temporarily silence warning being generated incorrectly.

This warning seems to sometimes get generated incorrectly beacuse of a bug
in webrender internally. For now we remove the warning to prevent it from
flooding job logs and causing timeouts in automation.

Review commit: https://reviewboard.mozilla.org/r/152180/diff/#index_header
See other reviews: https://reviewboard.mozilla.org/r/152180/

Comment 5

[Geoff Brown [:gbrown]]

Comment on attachment 8880834 [details]
Bug 1375843 - Temporarily silence warning being generated incorrectly.

https://reviewboard.mozilla.org/r/152180/#review157244

Thanks!

Comment 6

[Pulsebot]

Pushed by [e-mail]:
https://hg.mozilla.org/integration/autoland/rev/78f2464c6c1f
Temporarily silence warning being generated incorrectly. r=gbrown

Comment 7

[Carsten Book [:Tomcat]]

https://hg.mozilla.org/mozilla-central/rev/78f2464c6c1f