performance problem with gnome-shell and xorg with firefox extension

[i30817]

edit: i found the actual cause, disregard everything bellow the arrows

Seems like this bug: https://lkml.org/lkml/2014/8/8/445

The ubuntu kernels started to be compiled with CMA on. Which broke radeon. Which means that you should be getting loads of duplicates.

Anyway, i 'fixed' it with adding a command line switch to

GRUB_CMDLINE_LINUX_DEFAULT="quiet splash cma=0"

in /etc/default/grub

and running
sudo update-grub

You can check if you have this bug if you desktop get progressively slower and if dmesg is outputting lots of lines like this:
alloc_contig_range test_pages_isolated failed

<<<<<<<<< old wrong info starts here >>>>>>>>>>

Currently gnome shell occasionally has extreme performance problems so that they actually make the machine unresponsive. I'm attaching two oprof runs at the same time, one with xorg, the other with gnome shell, which are the processes top said were using the cpus. I actually started this instance of gnome-shell from a user console (because i had to kill the previous one and it didn't respawn.

The operf runs of gnome-shell and Xorg killed themselves spontaneously for some reason:
operf-record process killed by signal 13
operf-read process killed by signal 11
error running profiler

For what it is worth here they are. I have dbg libs installed for xorg, the kernel, gnome-shell and the ati driver in preparation of this but i think it might have been unnecessary to pinpoint the cause because the console output of the gnome-shell session showed me this before i had to kill it (again):

Window manager warning: Log level 16: /build/buildd/glib2.0-2.41.1/./gobject/gsignal.c:3102: signal id '568' is invalid for instance '0x1ded8e0'
console.error: ghostery:
  Message: TypeError: r.json is null
  Stack:
    checkLibraryVersion/<.onComplete@resource://gre/modules/addons/XPIProvider.jsm -> jar:file:///home/i30817/.<email address hidden>!/bootstrap.js -> resource://gre/modules/commonjs/toolkit/loader.js -> resource://firefox-at-ghostery-dot-com/ghostery/lib/background.js:2253:4
emit@resource://gre/modules/commonjs/toolkit/loader.js -> resource://gre/modules/commonjs/sdk/event/core.js:96:9
onreadystatechange@resource://gre/modules/addons/XPIProvider.jsm -> jar:file:///home/i30817/.<email address hidden>!/bootstrap.js -> resource://gre/modules/commonjs/toolkit/loader.js -> resource://gre/modules/commonjs/sdk/request.js:98:7

Window manager warning: Log level 16: /build/buildd/glib2.0-2.41.1/./gobject/gsignal.c:3102: signal id '568' is invalid for instance '0x1ded8e0'
Window manager warning: Log level 16: /build/buildd/glib2.0-2.41.1/./gobject/gsignal.c:3102: signal id '568' is invalid for instance '0x1ded8e0'
Window manager warning: Log level 16: /build/buildd/glib2.0-2.41.1/./gobject/gsignal.c:3102: signal id '568' is invalid for instance '0x1ded8e0'
Window manager warning: Log level 16: /build/buildd/glib2.0-2.41.1/./gobject/gsignal.c:3102: signal id '568' is invalid for instance '0x1ded8e0'
Window manager warning: Log level 16: /build/buildd/glib2.0-2.41.1/./gobject/gsignal.c:3102: signal id '568' is invalid for instance '0x1ded8e0'
Window manager warning: Log level 16: /build/buildd/glib2.0-2.41.1/./gobject/gsignal.c:3102: signal id '568' is invalid for instance '0x1ded8e0'
Window manager warning: Log level 16: /build/buildd/glib2.0-2.41.1/./gobject/gsignal.c:3102: signal id '568' is invalid for instance '0x1ded8e0'
Window manager warning: Log level 16: /build/buildd/glib2.0-2.41.1/./gobject/gsignal.c:3102: signal id '568' is invalid for instance '0x1ded8e0'
Window manager warning: Log level 16: /build/buildd/glib2.0-2.41.1/./gobject/gsignal.c:3102: signal id '568' is invalid for instance '0x1ded8e0'
Window manager warning: Log level 16: /build/buildd/glib2.0-2.41.1/./gobject/gsignal.c:3102: signal id '568' is invalid for instance '0x1ded8e0'
Window manager warning: Log level 16: /build/buildd/glib2.0-2.41.1/./gobject/gsignal.c:3102: signal id '568' is invalid for instance '0x1ded8e0'
Window manager warning: Log level 16: /build/buildd/glib2.0-2.41.1/./gobject/gsignal.c:3102: signal id '568' is invalid for instance '0x1ded8e0'
Window manager warning: Log level 16: /build/buildd/glib2.0-2.41.1/./gobject/gsignal.c:3102: signal id '568' is invalid for instance '0x1ded8e0'
Window manager warning: Log level 16: /build/buildd/glib2.0-2.41.1/./gobject/gsignal.c:3102: signal id '568' is invalid for instance '0x1ded8e0'
Window manager warning: Log level 16: /build/buildd/glib2.0-2.41.1/./gobject/gsignal.c:3102: signal id '568' is invalid for instance '0x1ded8e0'
Window manager warning: Log level 16: /build/buildd/glib2.0-2.41.1/./gobject/gsignal.c:3102: signal id '568' is invalid for instance '0x1ded8e0'
Window manager warning: Log level 16: /build/buildd/glib2.0-2.41.1/./gobject/gsignal.c:3102: signal id '568' is invalid for instance '0x1ded8e0'
Window manager warning: Log level 16: /build/buildd/glib2.0-2.41.1/./gobject/gsignal.c:3102: signal id '568' is invalid for instance '0x1ded8e0'
Window manager warning: Log level 16: /build/buildd/glib2.0-2.41.1/./gobject/gsignal.c:3102: signal id '568' is invalid for instance '0x1ded8e0'
Window manager warning: Log level 16: /build/buildd/glib2.0-2.41.1/./gobject/gsignal.c:3102: signal id '568' is invalid for instance '0x1ded8e0'
Window manager warning: Log level 16: /build/buildd/glib2.0-2.41.1/./gobject/gsignal.c:3102: signal id '568' is invalid for instance '0x1ded8e0'
Window manager warning: Log level 16: /build/buildd/glib2.0-2.41.1/./gobject/gsignal.c:3102: signal id '568' is invalid for instance '0x1ded8e0'
Window manager warning: Log level 16: /build/buildd/glib2.0-2.41.1/./gobject/gsignal.c:3102: signal id '568' is invalid for instance '0x1ded8e0'
Window manager warning: Log level 16: /build/buildd/glib2.0-2.41.1/./gobject/gsignal.c:3102: signal id '568' is invalid for instance '0x1ded8e0'
Window manager warning: Log level 16: /build/buildd/glib2.0-2.41.1/./gobject/gsignal.c:3102: signal id '568' is invalid for instance '0x1ded8e0'
Window manager warning: Log level 16: /build/buildd/glib2.0-2.41.1/./gobject/gsignal.c:3102: signal id '568' is invalid for instance '0x1ded8e0'
console.error: ghostery:
  Message: TypeError: r.json is null
  Stack:
    checkLibraryVersion/<.onComplete@resource://gre/modules/addons/XPIProvider.jsm -> jar:file:///home/i30817/.<email address hidden>!/bootstrap.js -> resource://gre/modules/commonjs/toolkit/loader.js -> resource://firefox-at-ghostery-dot-com/ghostery/lib/background.js:2253:4
emit@resource://gre/modules/commonjs/toolkit/loader.js -> resource://gre/modules/commonjs/sdk/event/core.js:96:9
onreadystatechange@resource://gre/modules/addons/XPIProvider.jsm -> jar:file:///home/i30817/.<email address hidden>!/bootstrap.js -> resource://gre/modules/commonjs/toolkit/loader.js -> resource://gre/modules/commonjs/sdk/request.js:98:7

Killed

My burning question is obviously, why the hell would a firefox extension make Xorg and gnome-shell unresponsive and not firefox, and don't you think you should fix it so its not possible?

ProblemType: Bug
DistroRelease: Ubuntu 14.10
Package: gnome-shell 3.12.2-1ubuntu4
ProcVersionSignature: Ubuntu 3.16.0-5.10-generic 3.16.0-rc6
Uname: Linux 3.16.0-5-generic x86_64
ApportVersion: 2.14.4-0ubuntu2
Architecture: amd64
CurrentDesktop: GNOME
Date: Fri Jul 25 22:25:34 2014
DisplayManager: gdm
GsettingsChanges: b'org.gnome.desktop.interface' b'gtk-im-module' b"'gtk-im-context-simple'"
InstallationDate: Installed on 2014-07-05 (20 days ago)
InstallationMedia: Ubuntu-GNOME 14.10 "Utopic Unicorn" - Alpha amd64 (20140624)
SourcePackage: gnome-shell
UpgradeStatus: No upgrade log present (probably fresh install)

[i30817 (i30817)]

Sigh... too soon. After disabling ghostery i still sometimes see spikes. Gnome shell output reports:

Window manager warning: Log level 16: /build/buildd/glib2.0-2.41.1/./gobject/gsignal.c:3102: signal id '568' is invalid for instance '0x7fba54008450'

(process:23644): GLib-CRITICAL **: g_slice_set_config: assertion 'sys_page_size == 0' failed
Window manager warning: last_focus_time (161964189) is greater than comparison timestamp (161963674). This most likely represents a buggy client sending inaccurate timestamps in messages such as _NET_ACTIVE_WINDOW. Trying to work around...
Window manager warning: Log level 16: /build/buildd/glib2.0-2.41.1/./gobject/gsignal.c:3102: signal id '568' is invalid for instance '0x7fba54008450'

whatever that is.

[Seth Arnold (seth-arnold)]

Thanks for taking the time to report this bug and helping to make Ubuntu better. We appreciate the difficulties you are facing, but this appears to be a "regular" (non-security) bug. I have unmarked it as a security issue since this bug does not show evidence of allowing attackers to cross privilege boundaries nor directly cause loss of data/privacy. Please feel free to report any other bugs you may find.