Bug#654194: libwebkitgtk-3.0-0: Infinite loop in RenderLayer::clipToRect.

[Matijs van Zuijlen]

Package: libwebkitgtk-3.0-0
Version: 1.6.1-5+b1
Severity: normal

This issue can be triggered as follows:

* Visit twitter.com
* Log in; the timeline is displayed.
* Click on any tweet. Normally this would cause a side pane to appear
  containing the tweet and some more info.

Result: The browser will go to 100% CPU and no longer respond.

I have tried this with both Epiphany and Midori, and the result is the
same.

Using gdb shows that the problem is in inContainingBlockChain, a static
function called by RenderLayer::clipToRect. It calls
currentBlock->containingBlock() to apparently loop through nested blocks.
However, for a RenderView object, this method returns the object itself,
causing an infinite loop.

The offending loop is in Source/WebCore/rendering/RenderLayer.cpp, line
2562; The relevant implementation of containingBlock is in
Source/WebCore/rendering/RenderView.cpp, line 270.

-- System Information:
Debian Release: wheezy/sid
  APT prefers unstable
  APT policy: (500, 'unstable'), (1, 'experimental')
Architecture: amd64 (x86_64)

Kernel: Linux 3.1.0-1-amd64 (SMP w/2 CPU cores)
Locale: LANG=en_US.utf8, LC_CTYPE=en_US.utf8 (charmap=UTF-8)
Shell: /bin/sh linked to /bin/bash

Versions of packages libwebkitgtk-3.0-0 depends on:
ii  libatk1.0-0                      2.2.0-2
ii  libc6                            2.13-24
ii  libcairo-gobject2                1.10.2-6.2
ii  libcairo2                        1.10.2-6.2
ii  libdbus-1-3                      1.4.16-1
ii  libdbus-glib-1-2                 0.98-1
ii  libenchant1c2a                   1.6.0-7
ii  libfontconfig1                   2.8.0-3
ii  libfreetype6                     2.4.8-1
ii  libgail-3-0                      3.2.3-1
ii  libgcc1                          1:4.6.2-9
ii  libgdk-pixbuf2.0-0               2.24.0-2
ii  libgeoclue0                      0.12.0-4
ii  libglib2.0-0                     2.30.2-4
ii  libgstreamer-plugins-base0.10-0  0.10.35-1
ii  libgstreamer0.10-0               0.10.35-1
ii  libgtk-3-0                       3.2.3-1
ii  libicu48                         4.8.1.1-1
ii  libjavascriptcoregtk-3.0-0       1.6.1-5+b1
ii  libjpeg8                         8c-2
ii  libpango1.0-0                    1.29.4-2
ii  libpng12-0                       1.2.46-3
ii  libsoup2.4-1                     2.36.1-1
ii  libsqlite3-0                     3.7.9-2
ii  libstdc++6                       4.6.2-9
ii  libwebkitgtk-3.0-common          1.6.1-5
ii  libx11-6                         2:1.4.4-4
ii  libxml2                          2.7.8.dfsg-5
ii  libxrender1                      1:0.9.6-2
ii  libxslt1.1                       1.1.26-8
ii  libxt6                           1:1.1.1-2
ii  zlib1g                           1:1.2.3.4.dfsg-3

libwebkitgtk-3.0-0 recommends no packages.

libwebkitgtk-3.0-0 suggests no packages.

-- no debconf information