Hello,

I was going to report it to mozilla but when I was trying to get a crash report with official build it was made clear to me that the official build is not affected, so this is problem only with Archlinux package and that's why I'm reporting it here. The official build can even use my profile: plugins, settings etc. and there is no problem.

I find that all videos which are in some of html5 technology (no flash) crash the browser when changing HD/SD mode or seeking forward.

1. Take any video from vimeo.com or even http://www.w3schools.com/html/html5_video.asp or https://olivegreenthemovie.com/#/play/1/10001

2. Scroll forward or change the quality

3. You get segmentation fault instantly

Now a bit about my setup:

Linux linux 3.18.6-1-ARCH #1 SMP PREEMPT Sat Feb 7 08:44:05 CET 2015 x86_64 GNU/Linux

I tried fresh profile, removed flashplayer, tried in safe mode etc.

[mk@linux ~]$ pacman -Qs nvidia
local/lib32-libcl 1.1-1
OpenCL library and ICD loader from NVIDIA (32-bit)
local/lib32-libvdpau 0.9-1
Nvidia VDPAU library
local/libcl 1.1-4
OpenCL library and ICD loader from NVIDIA
local/libvdpau 0.9-1
Nvidia VDPAU library
local/nvidia 346.35-6
NVIDIA drivers for linux
local/nvidia-cg-toolkit 3.1-3
NVIDIA Cg libraries
local/nvidia-libgl 346.35-2
NVIDIA drivers libraries symlinks
local/nvidia-utils 346.35-2
NVIDIA drivers utilities
local/opencl-nvidia 346.35-2
OpenCL implemention for NVIDIA

[mk@linux ~]$ pacman -Qs nouveau
local/lib32-mesa 10.4.5-1
an open-source implementation of the OpenGL specification (32-bit)
local/mesa 10.4.5-1
an open-source implementation of the OpenGL specification

[mk@linux ~]$ pacman -Qs cairo
local/cairo 1.14.0-2
[mk@linux ~]$ pacman -Qs firefox
local/firefox 36.0-1
Standalone web browser from mozilla.org
local/firefox-i18n-pl 36.0-1
Polish language pack for Firefox

[mk@linux ~]$ pacman -Qs gst
local/gnome-video-effects 0.4.1-1
A collection of GStreamer effects
local/gst-libav 1.4.5-1
Gstreamer libav Plugin
local/gst-plugins-base 1.4.5-1
GStreamer Multimedia Framework Base Plugins
local/gst-plugins-base-libs 1.4.5-1
GStreamer Multimedia Framework Base Plugin libraries
local/gst-plugins-good 1.4.5-1
GStreamer Multimedia Framework Good Plugins
local/gstreamer 1.4.5-1
GStreamer Multimedia Framework
local/gstreamer-vaapi 0.5.10-1
GStreamer Multimedia Framework VA Plugins
local/gstreamer0.10 0.10.36-4
GStreamer Multimedia Framework
local/gstreamer0.10-bad 0.10.23-8
GStreamer Multimedia Framework Bad Plugin libraries (gst-plugins-bad)
local/gstreamer0.10-bad-plugins 0.10.23-8 (gstreamer0.10-plugins)
GStreamer Multimedia Framework Bad Plugins (gst-plugins-bad)
local/gstreamer0.10-base 0.10.36-3
GStreamer Multimedia Framework Base plugin libraries
local/gstreamer0.10-base-plugins 0.10.36-3 (gstreamer0.10-plugins)
GStreamer Multimedia Framework Base Plugins (gst-plugins-base)
local/gstreamer0.10-ffmpeg 0.10.13-2 (gstreamer0.10-plugins)
Gstreamer FFMpeg Plugin
local/gstreamer0.10-good 0.10.31-6
GStreamer Multimedia Framework Good plugin libraries
local/gstreamer0.10-good-plugins 0.10.31-6 (gstreamer0.10-plugins)
GStreamer Multimedia Framework Good Plugins (gst-plugins-good)
local/gstreamer0.10-mm 0.10.11-1
C++ interface for GStreamer 0.10
local/gstreamer0.10-ugly 0.10.19-13
GStreamer Multimedia Framework Ugly plugin libraries
local/gstreamer0.10-ugly-plugins 0.10.19-13 (gstreamer0.10-plugins)
GStreamer Multimedia Framework Ugly Plugins (gst-plugins-ugly)
local/gstreamer0.10-vaapi 0.5.9-1
GStreamer Multimedia Framework VA Plugins
local/gstreamermm 1.4.3-1
C++ interface for GStreamer
local/phonon-qt4-gstreamer 4.8.2-1
Phonon GStreamer backend for Qt4
local/phonon-qt5-gstreamer 4.8.2-1
Phonon GStreamer backend for Qt5

Firefox tech support info:


Application Basics
------------------

Name: Firefox
Version: 36.0
User Agent: Mozilla/5.0 (X11; Linux x86_64; rv:36.0) Gecko/20100101 Firefox/36.0
Multiprocess Windows: 0/1

Extensions
----------

Name: Adblock Plus
Version: 2.6.7
Enabled: true
ID: {d10d0bf8-f5b5-c8b4-a8b2-2b9879e08c5d}

Name: Allegro.pl Search
Version: 1.2
Enabled: true
ID: allegrosearch@matylla.pl

Name: Cookies Manager+
Version: 1.5.2
Enabled: true
ID: {bb6bc1bb-f824-4702-90cd-35e2fb24f25d}

Name: DownThemAll!
Version: 2.0.18
Enabled: true
ID: {DDC359D1-844A-42a7-9AA1-88A850A938A8}

Name: Easy Youtube Video Downloader Express
Version: 7.38
Enabled: true
ID: {b9acf540-acba-11e1-8ccb-001fd0e08bd4}

Name: Element Hiding Helper for Adblock Plus
Version: 1.3.1
Enabled: true
ID: elemhidehelper@adblockplus.org

Name: Flashblock
Version: 1.5.18
Enabled: true
ID: {3d7eb24f-2740-49df-8937-200b1cc08f8a}

Name: Ghostery
Version: 5.4.2
Enabled: true
ID: firefox@ghostery.com

Name: google-no-tracking-url
Version: 1.3.1
Enabled: true
ID: jid1-zUrvDCat3xoDSQ@jetpack

Name: Vacuum Places Improved
Version: 1.2
Enabled: true
ID: VacuumPlacesImproved@lultimouomo-gmail.com

Name: YesScript
Version: 2.0
Enabled: true
ID: yesscript@userstyles.org

Name: Preloader (for Firefox)
Version: 1.1
Enabled: false
ID: {8a8c1ada-2504-45c6-a2d2-265591abbd00}

Graphics
--------

Adapter Description: NVIDIA Corporation -- GeForce GT 610/PCIe/SSE2
Device ID: GeForce GT 610/PCIe/SSE2
Driver Version: 4.5.0 NVIDIA 346.35
GPU Accelerated Windows: 0/1 Basic
Vendor ID: NVIDIA Corporation
WebGL Renderer: NVIDIA Corporation -- GeForce GT 610/PCIe/SSE2
windowLayerManagerRemote: false
AzureCanvasBackend: cairo
AzureContentBackend: cairo
AzureFallbackCanvasBackend: none
AzureSkiaAccelerated: 0

Important Modified Preferences
------------------------------

accessibility.typeaheadfind.flashBar: 0
browser.cache.disk.capacity: 0
browser.cache.disk.smart_size_cached_value: 358400
browser.cache.disk.smart_size.enabled: false
browser.cache.disk.smart_size.first_run: false
browser.cache.disk.smart_size.use_old_max: false
browser.cache.frecency_experiment: 2
browser.display.background_color: #D4D4D4
browser.places.smartBookmarksVersion: 7
browser.search.useDBForOrder: true
browser.sessionstore.upgradeBackup.latestBuildID: 20150224222119
browser.startup.homepage: about:home
browser.startup.homepage_override.buildID: 20150224222119
browser.startup.homepage_override.mstone: 36.0
dom.mozApps.used: true
dom.w3c_touch_events.expose: false
extensions.lastAppVersion: 36.0
general.autoScroll: true
media.gmp-gmpopenh264.lastUpdate: 1423297139
media.gmp-gmpopenh264.version: 1.3
media.gmp-manager.lastCheck: 1424990145
media.mediasource.enabled: true
network.cookie.cookieBehavior: 3
network.cookie.prefsMigrated: true
network.dns.disableIPv6: true
network.http.pipelining: true
places.database.lastMaintenance: 1424990146
places.history.expiration.transient_current_max_pages: 103744
plugin.disable_full_page_plugin_for_types: application/pdf
plugin.importedState: true
plugin.soname.list: libXt.so:libXext.so
privacy.sanitize.migrateFx3Prefs: true
security.disable_button.openCertManager: false
security.disable_button.openDeviceManager: false
security.OCSP.disable_button.managecrl: false
storage.vacuum.last.index: 1
storage.vacuum.last.places.sqlite: 1423490595

Important Locked Preferences
----------------------------

JavaScript
----------

Incremental GC: true

Accessibility
-------------

Activated: false
Prevent Accessibility: 0

Library Versions
----------------

NSPR
Expected minimum version: 4.10.8
Version in use: 4.10.8

NSS
Expected minimum version: 3.17.4 Basic ECC
Version in use: 3.17.4 Basic ECC

NSSSMIME
Expected minimum version: 3.17.4 Basic ECC
Version in use: 3.17.4 Basic ECC

NSSSSL
Expected minimum version: 3.17.4 Basic ECC
Version in use: 3.17.4 Basic ECC

NSSUTIL
Expected minimum version: 3.17.4
Version in use: 3.17.4

Experimental Features
---------------------

Sandbox
-------

Seccomp-BPF (System Call Filtering): true
Media Plugin Sandboxing: true

Other detailed information on my system can be found here:
https://bbs.archlinux.org/viewtopic.php?pid=1503456#p1503456