All 5 of those crash reports show this. Firefox 40.0.2 Crash Report [@ libc-2.11.1.so@0x2d811 ]

And the related Bug report summary says this - Bug 1196494 - _XPrivSyncFunction: Assertion `dpy->synchandler == _XPrivSyncFunction' failed with Firefox 40.0.2 (and also latest aurora build); older libX11?

Was the pref you toggled in 37.0.1 - layers.offmainthreadcomposition.enabled?

Thank you for the quick reply. No. The change I made required setting this to false: media.gstreamer.enabled = true

So this is not a a video driver issue?

In here

https://support.mozilla.org/en-US/questions/1075880

you will see a person having problems in unbutu again what i did was to install debian 8.1 in a virtual machine and I tested firefox x64 nightly 42.0.a1 you can find the latest version in here

https://ftp.mozilla.org/pub/mozilla.org/firefox/nightly/latest-trunk/firefox-43.0a1.en-US.linux-x86_64.tar.bz2

the first problem i found was my favorite plugin no script was not supporting this version so i found another version that was allowing the plugin to work without a problem I found the version 40.0b9 and I i was getting the errors

(firefox:1784): Gtk-CRITICAL **: IA__gtk_clipboard_set_with_data: assertion 'targets != NULL' failed (firefox:1784): Gtk-CRITICAL **: IA__gtk_clipboard_set_with_data: assertion 'targets != NULL' failed

In the terminal I used as an output by typing “./firefox&” when the other person did the same he replied with so many errors I couldn’t believe it!?

Finally I did download the source of nightly 40.0b9 in order to make a compile and see if there was any incomparability with the software you can’t imagine how many new libraries I forced to download and install and any time 1 was needed I was doing su root because I was logged in as simple user.

In the end I manage to install all the new libraries and as you see in the images I unload I was be able to see and the mobile version of this side without a problem can you follow the same steps?

I did upload all the photos of the make in here:

https://support.mozilla.org/questions/1076723

I am not able to follow the same steps, that you did. First, because I'm using a no longer supported version Ubuntu 10.04 LTS. Second, I'm not sure that video is the reason for Firefox 40.0.2 crashing. I do appreciate your great effort to solve this problem for yourself or someone running Ubuntu 14.04; but I don't think I can extract any help from your experience. I guess I will have to back up this HDD, and then go get Ubuntu 15.04 and install it on this machine--Inspiron 1525 Laptop---which is a much older model, and chipset. I have tried Ubuntu 12.04, a while back and my machine ran slow as a turtle. I uninstalled it, out of frustration. Thanks anyway, for your help. I'm thinking my crashing problem is still because of my "out of support" Ubuntu version. It pisses me off because I stopped using Windows in 2006 to get away from their constant updates corrections, and versions of OS. Like they say SHIT by any other name still stinks. I hate that I can't continue using something I like, just because it's old. Like me, I'm 65 years old and am a retired IBM EE Test (hardware) technician, in Electrical and Optical Test of IBM Mainframe hardware. Just call me dinosaur. I guess that doesn't get me much respect anymore. Thanks again. :-)

Is looks like a problem with Xrender calling some kernel API. linux-gate.so that shows in the crash report is not a real executable, but merely indicates that an application want to invoke the Linux kernel. Such crashes are always difficult to investigate. If you recently updated kernel components or drivers that run at kernel level then you could try to revert these.

You can check the prefs.js file in the profile folder to see if it has any gfx lines like:

• user_pref("gfx.xrender.enabled", false);

If you see this line then try to remove it and possibly other present gfx.* lines as well. Otherwise try to add a line to disable Xrender.

• user_pref("gfx.xrender.enabled", false);

The Firefox profile folder is in this hidden location: ~/.mozilla/firefox/<profile>/

• http://kb.mozillazine.org/Profile_folder_-_Firefox

I did not find

• user_pref("gfx.xrender.enabled", false);

listed in my ~/.mozilla/firefox/<profile>/

I also made sure that I was using the nvidia driver instead of the nouveau driver: "Searching for available drivers... Unknown driver: xorg:nvidia_current Use --list to see available drivers

~$ sudo jockey-text -e xorg:nvidia_current --list

firmware:b43 - Broadcom B43 wireless driver (Free, Enabled, In use) kmod:wl - Broadcom STA wireless driver (Proprietary, Disabled, Not in use) robotics1-end:~$ "

Again, I'm using Ubuntu 10.04 LTS. <----this is no longer a supported OS. I think I have no choice but to upgrade to Ubuntu 15.04 if I want to continue using Firefox browser. I hate it. I hate it. I hate it. I hate it. I hate it. I hate it. I hate it. I hate it. I hate it. But I guess I'll HAVE TO DO IT. Thank you anyway. Shobuz99

relax I was using slagware before i get to bedian 8.1 and in there nothing was automatic there was not ap-get or sudo commands i had to search by my self for all new drivers or new libraries to download and install them the procedure was alwas the same

./cofingure make install ./firefox&

you can download and instal a new kernel if you like is really nothing linux is free so find a version of mozila you like

https://ftp.mozilla.org/pub/firefox/releases/

or a nigtly you like

http://archive.mozilla.org/pub/firefox/nightly/

and we can do the make together if you like.

Having Firefox Nightly available could be an advantage for test and comparison purposes. IIRC pub44 use manual CLI methods and takes hours to put Firefox on Debian 8. I reckon most users could put the Mozilla build on in about 10 minutes: say 3min to read the instructions, 3min to download, 3 min to complete. It's even easier on Ubuntu.

• Install Firefox on Linux
  • https://help.ubuntu.com/community/FirefoxNewVersion
    • https://help.ubuntu.com/community/FirefoxNewVersion/MozillaBuilds
• http://kb.mozillazine.org/Testing_pre-release_versions#Installing_multiple_versions

If your Cannonical Fx40 is unusable due to crashing Then I suggest whilst you investigate that and try to fund a work around or solution, that you put Mozilla Fx38.2 ESR on as an additional bowser. That is not something Mozilla or this site will advise as a solution to general issues but it is a useful workaround and method of having a relatively secure browser. In this instance we may expect the ESR version NOT to be affected by this Crash Issue.

• https://www.mozilla.org/en-US/firefox/organizations/faq/
  • https://www.mozilla.org/en-US/firefox/organizations/all/

Did you decide to upgrade your OS ? The supported Ubuntu Releases e.g (12.04 LTS),14.04 LTS & 15.04 are fully supported by Firefox. If you run into crashes on a supported OS it may be worth filing a bug.

Firefox Graphix Changes (OMTC) This article explains the background of the recent relevant Firefox changes

• Mozilla Gfx Team Blog https://mozillagfx.wordpress.com/2015/05/19/off-main-thread-compositing-on-linux/
  Off-main-thread compositing on Linux

... OMTC on Linux, in its current state is still pretty new and comes with some improvements and regressions we are confident that we will be able to catch up with all of the regressions eventually but, as usual, don’t hesitate to file bugs at bugzilla.mozilla.org. ...

It took me half a day to compile 40.0b9i in debian 8.1 that part is true mostly because the emulation in the work station was using only 2 cores at 3Ghz and the workstation was not allowing me to have a graphics card with more than 128 Mbytes memory.

All the time I was using su root to download and install all the libraries because I wasn’t loggin as root to play on internet I never do but in the end the effort was worth it I was be able to see even the mobile version of this site something I can’t do with the fixed exe x32bits version 38.0.5 for my windows vista x64 and I did upload all the images yet noone did chose me as the best solution.

In the end what more to do in here? Sometimes is boring.

John99, Thank you for your help. "Did you decide to upgrade your OS ?" Yes, but I haven't begun the process yet. I've been using Ubuntu 10.04 LTS since it was released, and I have also been using a very old version of Dreamweaver MX for my web design app. I know that 11 years is a long time to use OS and application software; BUT it is MY choice. So, I must move some files off one of my SATA HDD's and format it. Then I'll install Ubuntu 15.04 because it's the latest version AFAIK. I have several machines, with varying OS. Such as Win 7 and Vista, as well as two laps using Ubuntu 10.04 LTS. I have multiple HDD's with files that I need to keep, for archive purposes. If Ubuntu 15.04 will allow me to run Dreamweaver MX 2004, then I will install it on my fastest machine. Otherwise, I will be continuing to use Ubuntu 10.04 LTS on my 'headless' machine. Thank you for your help. I'll let you know how all this goes, if you're interested (which I doubt you are). Shobuz99

as i said to someone is better to try solaris 11.2 version you can download it from here:

http://www.oracle.com/technetwork/server-storage/solaris11/downloads/install-2245079.html

and list we will compile firefox at x128bits nobody done a thing like this.