X server segfaults immediately at startup

[Vince]

This system was working perfectly 3 months ago. I turned it off and left it off until yesterday.
When I came back to it and turned it on, it worked initially but then the nvidia video card
(nvidia GeForce GT 630) decided to die. I replaced the video card with an nvidia GeForce GT 710
and hit this issue. The machine also has integrated Intel graphics which I am not using.

The system boots fine, I see BIOS boot messages and linux kernel messages until X tries to start.
After it does that, nothing is displayed on screen. If I try to switch to another VT with
 <c><a><F2> for example, I get no output then either.

Extract from /var/log/Xorg.0.log

[ 20.839] (EE) Backtrace:
[ 20.839] (EE) 0: /usr/lib/xorg/Xorg (xorg_backtrace+0x4e) [0x55ef19ccae0e]
[ 20.839] (EE) 1: /usr/lib/xorg/Xorg (0x55ef19b19000+0x1b5b79) [0x55ef19cceb79]
[ 20.839] (EE) 2: /lib/x86_64-linux-gnu/libpthread.so.0 (0x7fc802cbb000+0x11390) [0x7fc802ccc390]
[ 20.839] (EE) 3: /usr/lib/xorg/Xorg (RRProviderAutoConfigGpuScreen+0x42) [0x55ef19c38232]
[ 20.839] (EE) 4: /usr/lib/xorg/Xorg (InitOutput+0x5bd) [0x55ef19bb1c7d]
[ 20.839] (EE) 5: /usr/lib/xorg/Xorg (0x55ef19b19000+0x582d6) [0x55ef19b712d6]
[ 20.839] (EE) 6: /lib/x86_64-linux-gnu/libc.so.6 (__libc_start_main+0xf0) [0x7fc802911830]
[ 20.839] (EE) 7: /usr/lib/xorg/Xorg (_start+0x29) [0x55ef19b5b449]
[ 20.839] (EE)
[ 20.839] (EE) Segmentation fault at address 0x130
[ 20.839] (EE)
Fatal server error:
[ 20.839] (EE) Caught signal 11 (Segmentation fault). Server aborting
[ 20.839] (EE)
[ 20.839] (EE)
Please consult the The X.Org Foundation support
         at http://wiki.x.org
 for help.

I am using the nvidia drivers and they seem not to be loading for some reason.
I need to use them for vdpau support.
Here is where the X server tries to load the nvidia driver, from earlier in the same log file:

...
[ 20.823] (II) xfree86: Adding drm device (/dev/dri/card0)
[ 20.823] (II) xfree86: Adding drm device (/dev/dri/card1)
[ 20.826] (--) PCI: (0:0:2:0) 8086:29c2:8086:5044 rev 2, Mem @ 0x9b400000/524288, 0x80000000/268435456, 0x9b300000/1048576, I/O @ 0
x00004430/8
[ 20.826] (--) PCI:*(0:1:0:0) 10de:128b:1462:8c93 rev 161, Mem @ 0x9a000000/16777216, 0x90000000/134217728, 0x98000000/33554432, I/
O @ 0x00003000/128, BIOS @ 0x????????/131072
[ 20.826] (WW) "glamoregl" will not be loaded unless you've specified it to be loaded elsewhere.
[ 20.826] (II) "glx" will be loaded by default.
[ 20.826] (II) LoadModule: "glx"
[ 20.826] (II) Loading /usr/lib/xorg/modules/extensions/libglx.so
[ 20.827] (II) Module glx: vendor="X.Org Foundation"
[ 20.827] compiled for 1.19.6, module version = 1.0.0
[ 20.827] ABI class: X.Org Server Extension, version 10.0
[ 20.827] (==) Matched nvidia as autoconfigured driver 0
[ 20.828] (==) Matched nouveau as autoconfigured driver 1
[ 20.828] (==) Matched intel as autoconfigured driver 2
[ 20.828] (==) Matched nvidia as autoconfigured driver 3
[ 20.828] (==) Matched nouveau as autoconfigured driver 4
[ 20.828] (==) Matched modesetting as autoconfigured driver 5
[ 20.828] (==) Matched fbdev as autoconfigured driver 6
[ 20.828] (==) Matched vesa as autoconfigured driver 7
[ 20.828] (==) Assigned the driver to the xf86ConfigLayout
[ 20.828] (II) LoadModule: "nvidia"
[ 20.829] (WW) Warning, couldn't open module nvidia
[ 20.829] (II) UnloadModule: "nvidia"
[ 20.829] (II) Unloading nvidia
[ 20.829] (EE) Failed to load module "nvidia" (module does not exist, 0)
[ 20.829] (II) LoadModule: "nouveau"
[ 20.829] (II) Loading /usr/lib/xorg/modules/drivers/nouveau_drv.so
[ 20.830] (II) Module nouveau: vendor="X.Org Foundation"
[ 20.830] compiled for 1.19.5, module version = 1.0.15
[ 20.830] Module class: X.Org Video Driver
[ 20.830] ABI class: X.Org Video Driver, version 23.0
[ 20.830] (II) LoadModule: "intel"
[ 20.830] (II) Loading /usr/lib/xorg/modules/drivers/intel_drv.so
[ 20.830] (II) Module intel: vendor="X.Org Foundation"
[ 20.830] compiled for 1.19.5, module version = 2.99.917
[ 20.830] Module class: X.Org Video Driver
[ 20.830] ABI class: X.Org Video Driver, version 23.0
...

Steps I have taken:
 - reinstall xserver-xorg-hwe-16.04, xserver-xorg-core-hwe-16.04, xserver-xorg-video-all-hwe-16.04 and nvidia-384
 - rebooted a few times to check for a race condition

ProblemType: Bug
DistroRelease: Ubuntu 16.04
Package: xorg 1:7.7+13ubuntu3.1
ProcVersionSignature: Ubuntu 4.15.0-55.60~16.04.2-generic 4.15.18
Uname: Linux 4.15.0-55-generic x86_64
NonfreeKernelModules: nvidia_drm nvidia_modeset nvidia
ApportVersion: 2.20.1-0ubuntu2.19
Architecture: amd64
Date: Sun Jul 28 22:23:42 2019
InstallationDate: Installed on 2016-11-12 (988 days ago)
InstallationMedia: Ubuntu-Server 16.04.1 LTS "Xenial Xerus" - Release amd64 (20160719)
SourcePackage: xorg
Symptom: display
UpgradeStatus: No upgrade log present (probably fresh install)

[Vince (xindidu)]

Tried booting the system with linux-image-4.4.0-154-generic. X works on this kernel.
Tried booting the system with linux-image-4.15.0-47-generic. X works on this kernel.

Presumably there is some bad interaction between the nvidia module and 4.15.0-55-generic.

[Daniel van Vugt (vanvugt)]

Please resubmit that crash file using this command:

  ubuntu-bug /PATH/TO/CRASH/FILE

and tell us the number of the new bug created.

If that doesn't work then please look at https://errors.ubuntu.com/user/ID where ID is the content of file /var/lib/whoopsie/whoopsie-id on the machine. Do you find any links to recent problems on that page? If so then please send the links to us.

[Daniel van Vugt (vanvugt)]

Thank you for taking the time to report this bug and helping to make Ubuntu better. This particular bug has already been reported and is a duplicate of bug 1724901, so it is being marked as such. Please look at the other bug report to see if there is any missing information that you can provide, or to see if there is a workaround for the bug. Additionally, any further discussion regarding the bug should occur in the other report. Feel free to continue to report any other bugs you may find.

[Vince (xindidu)]

Given the duplicate status, is the ubuntu-bug report still required?

[Daniel van Vugt (vanvugt)]

Not really, thanks.

Though if you wanted to go ahead with comment #4 it would provide a more certain confirmation that this is the same bug.

[Vince (xindidu)]

I gave ubuntu-bug a whirl and ... maybe it worked.

It prompted me whether I wanted to send the report. I said 'S' as the first option I chose and after
printing several screens of "........." it exited with status 0. It didn't print any bug number as
far as I could see.

The whoopise id file is there but following the link as you describe gives me a page saying
"No errors have been reported from this system".