1489644 - Scrolling Francine panics at 'attempt to multiply with overflow', gfx/webrender/src/texture_allocator.rs:57

Status: RESOLVED FIXED

(Core :: Graphics: WebRender, defect, P2)

Description

[Bobby Holley (:bholley)]

STR: Debug [1] build, OSX, 3840x2160 screen, latest m-c [2]. Load [3] and scroll down.

Panic occurs here: https://searchfox.org/mozilla-central/rev/6201a9e0067cf6af118c6a99ae9314b8ceb2c4d5/gfx/webrender/src/texture_allocator.rs#57

Overflows in the texture allocator seem likely to cause bugs in the wild, so we should fix this.

[1] Also DMD, but that's probably not relevant.
[2] https://hg.mozilla.org/mozilla-central/rev/b8905df54d01
[3] http://diana-adrianne.com/purecss-francine/

Comment 1

[Bobby Holley (:bholley)]

Attachment: stack

attached a stack from lldb. I've confirmed it happens with the screen unplugged and the window non-maximized, so presumably it's a reasonably-robust STR.

Comment 2

[Darkspirit]

Debian Testing, KDE, Xorg, Nvidia GTX 1060 (driver 390.77)

> 1:22.97 INFO: thread 'WRRenderBackend#1' panicked at 'attempt to multiply with overflow', gfx/webrender/src/texture_allocator.rs:57:34

RUST_BACKTRACE=1 mozregression --good 2018-08-20 --bad 2018-09-07 -B debug --pref gfx.webrender.all:true -a http://diana-adrianne.com/purecss-francine/
> 9:05.21 INFO: Last good revision: 43b1ea339d12e26266d7946b74eb0a7304157aa6
> 9:05.21 INFO: First bad revision: 82efdb13962c299f4501c9f4ee3a4608a4fef85a
> 9:05.21 INFO: Pushlog:
> https://hg.mozilla.org/integration/mozilla-inbound/pushloghtml?fromchange=43b1ea339d12e26266d7946b74eb0a7304157aa6&tochange=82efdb13962c299f4501c9f4ee3a4608a4fef85a

> 82efdb13962c	Jeff Muizelaar — Bug 1487429. Update tests for WebRender changes.
> 595a9385a0b0	Jeff Muizelaar — Bug 1487429. Update webrender to 69dae1fe743bf3656d532672366e7193b041b6f7

Comment 3

[Jeff Muizelaar [:jrmuizel]]

This was your change Glenn: https://github.com/servo/webrender/pull/2995

Comment 4

[Glenn Watson [:gw]]

I can reproduce the panic in current Gecko. I'm unable to reproduce it with https://github.com/servo/webrender/pull/3030 applied to my local Gecko. That patch includes tighter calculation of bounding rects for clip masks, which I suspect is the fix for this bug.