1178521 - Glitching while scrolling second half of long document

Status: NEW

(Core :: Graphics, defect, P3)

Description

[Botond Ballo [:botond]]

Attachment: long-document-1.png

STR:
  1. Load [1] in today's nightly on Linux.
  2. Scroll down by dragging the scroll thumb.

Once you get to roughly the second half of the document, the text turns into vertical lines, as shown in the attachment. When you release the thumb, the vertical lines persist.

If you scroll via the mouse wheel or the scrollbar arrows after releasing the thumb, the vertical lines are replaced by text, but there is a rendering glitch as you scroll where one line of text is distorted (I couldn't take a screenshot of this because taking a screenshot causes a repaint which fixes the rendering.)

Returning to the first half of the document restores rendering to normal.

The page in question is a bit over 700,000 lines long.

[1] http://ftp.mozilla.org/pub/mozilla.org/firefox/try-builds/[e-mail]-b6cf99ececbe/try-linux64-debug/try_ubuntu64_vm-debug_test-mochitest-e10s-3-bm67-tests1-linux64-build352.txt.gz

Comment 1

[u279076]

I can reproduce this in a Fedora 22 x86_64 VM. The regression dates back to Firefox 29.

mozilla-central:
================
Last good revision: 4b242b19b006
First bad revision: c71b40e7fab8
Pushlog: http://hg.mozilla.org/mozilla-central/pushloghtml?fromchange=4b242b19b006&tochange=c71b40e7fab8