GDM freeze

[Nish Aravamudan]

Here is what I know so far:

After rebooting this morning on Bionic (after receiving the gnome theme updates, I think), upon reboot the CPU pegs and the greeter is never displayed (there is a graphics system running, but I'm not sure what it's doing). My num lock / caps lock keys work, but the touchpad on the laptop does nothing to the mouse.

If I boot with nomodeset, greeter does not freeze.

Finally, in either case, I am now unable to use my external monitor, which worked fine before (connected over a USB-C to HDMI dongle).

ProblemType: Bug
DistroRelease: Ubuntu 18.04
Package: xorg 1:7.7+19ubuntu5
ProcVersionSignature: Ubuntu 4.15.0-10.11-generic 4.15.3
Uname: Linux 4.15.0-10-generic x86_64
ApportVersion: 2.20.8-0ubuntu10
Architecture: amd64
CompizPlugins: No value set for `/apps/compiz-1/general/screen0/options/active_plugins'
CompositorRunning: None
CurrentDesktop: GNOME
Date: Mon Mar 5 11:47:53 2018
DistUpgraded: Fresh install
DistroCodename: bionic
DistroVariant: ubuntu
ExtraDebuggingInterest: Yes, including running git bisection searches
GpuHangFrequency: This is the first time
GraphicsCard:
 Intel Corporation HD Graphics 520 [8086:1916] (rev 07) (prog-if 00 [VGA controller])
   Subsystem: Lenovo Skylake GT2 [HD Graphics 520] [17aa:3800]
InstallationDate: Installed on 2015-12-17 (809 days ago)
InstallationMedia: Ubuntu-GNOME 15.10 "Wily Werewolf" - Release amd64 (20151021)
MachineType: LENOVO 80MK
ProcKernelCmdLine: BOOT_IMAGE=/vmlinuz-4.15.0-10-generic root=UUID=c0742e7a-578f-4be5-bd9e-05b9e92f5b00 ro noprompt persistent quiet splash nomodeset
SourcePackage: xorg
Symptom: display
Title: Xorg freeze
UpgradeStatus: No upgrade log present (probably fresh install)
dmi.bios.date: 10/29/2015
dmi.bios.vendor: LENOVO
dmi.bios.version: C6CN34WW
dmi.board.asset.tag: NO Asset Tag
dmi.board.name: VIUU4
dmi.board.vendor: LENOVO
dmi.board.version: SDK0K45914 WIN
dmi.chassis.asset.tag: NO Asset Tag
dmi.chassis.type: 10
dmi.chassis.vendor: LENOVO
dmi.chassis.version: Lenovo YOGA 900-13ISK
dmi.modalias: dmi:bvnLENOVO:bvrC6CN34WW:bd10/29/2015:svnLENOVO:pn80MK:pvrLenovoYOGA900-13ISK:rvnLENOVO:rnVIUU4:rvrSDK0K45914WIN:cvnLENOVO:ct10:cvrLenovoYOGA900-13ISK:
dmi.product.family: IDEAPAD
dmi.product.name: 80MK
dmi.product.version: Lenovo YOGA 900-13ISK
dmi.sys.vendor: LENOVO
version.compiz: compiz 1:0.9.13.1+18.04.20180302-0ubuntu1
version.libdrm2: libdrm2 2.4.90-1
version.libgl1-mesa-dri: libgl1-mesa-dri 18.0.0~rc4-1ubuntu3
version.libgl1-mesa-glx: libgl1-mesa-glx 18.0.0~rc4-1ubuntu3
version.xserver-xorg-core: xserver-xorg-core 2:1.19.6-1ubuntu2
version.xserver-xorg-input-evdev: xserver-xorg-input-evdev 1:2.10.5-1ubuntu1
version.xserver-xorg-video-ati: xserver-xorg-video-ati 1:7.10.0-1
version.xserver-xorg-video-intel: xserver-xorg-video-intel 2:2.99.917+git20171229-1
version.xserver-xorg-video-nouveau: xserver-xorg-video-nouveau 1:1.0.15-2
xserver.bootTime: Mon Mar 5 11:17:58 2018
xserver.configfile: default
xserver.errors:
 open /dev/dri/card0: No such file or directory
 open /dev/dri/card0: No such file or directory
 Screen 0 deleted because of no matching config section.
 AIGLX: reverting to software rendering
xserver.logfile: /var/log/Xorg.0.log
xserver.outputs:

xserver.version: 2:1.19.6-1ubuntu2

[Daniel van Vugt (vanvugt)]

Can you find any crash files in /var/crash ?

If so then please run:

  ubuntu-bug /var/crash/YOURFILE.crash

and tell us the new bug ID.

[Nish Aravamudan (nacc)]

@vanvugt: no, as it's not crashed (afaict), it's just 100% cpu (based upon fans). Numlock is still responsive as is sysrq, but i can't get to any ttys (that is, ctrl+alt+f2, etc don't seem to work).

I even tried booting with 'text' and annoyingly gdm still started (I might be misremembering how to do that, though).

Any suggestions on how to force a crash?

I might reboot now and just leave it to see if it eventually progresses.

[Nish Aravamudan (nacc)]

Oh also the splash screen correctly displays on both monitors, so i think it must be in X that the multiple displays fail.

I'll see if I can figure out how to get to a temrinal.

[Nish Aravamudan (nacc)]

Hrm, I'm not entirely sure what just changed. I rebooted and unlike before, I hit Escape at the splash screen, and the GDM greeter showed up just fine (after hitting Escape again to go back to graphics mode). I'll see if that's reproducible shortly.

[dino99 (9d9)]

Also now get a 'smooth' freeze (kind of race, as the hdd is heavily used before getting the login screen. But booting with 'plymooth:debug' kernel option, journalctl has logged:

***********
Mar 06 04:19:47 ubuntu plymouth[660]: [./ply-boot-client.c:183] ply_boot_client_connect:could not connect to /org/freedesktop/plymouthd: Connection refused
Mar 06 04:19:47 ubuntu plymouth[660]: [./ply-boot-client.c:184] ply_boot_client_connect:trying old fallback path /ply-boot-protocol
Mar 06 04:19:47 ubuntu plymouth[660]: [./ply-boot-client.c:190] ply_boot_client_connect:could not connect to /ply-boot-protocol: Connection refused
Mar 06 04:19:47 ubuntu plymouth[660]: [./plymouth.c:1121] main:daemon not running
Mar 06 04:19:47 ubuntu plymouth[660]: [./ply-boot-client.c:810] ply_boot_client_detach_from_event_loop:detaching from event loop
Mar 06 04:19:56 ubuntu plymouth[1011]: [./ply-boot-client.c:183] ply_boot_client_connect:could not connect to /org/freedesktop/plymouthd: Connection refused
Mar 06 04:19:56 ubuntu plymouth[1011]: [./ply-boot-client.c:184] ply_boot_client_connect:trying old fallback path /ply-boot-protocol
Mar 06 04:19:56 ubuntu plymouth[1011]: [./ply-boot-client.c:190] ply_boot_client_connect:could not connect to /ply-boot-protocol: Connection refused
Mar 06 04:19:56 ubuntu plymouth[1011]: [./plymouth.c:1121] main:daemon not running
Mar 06 04:19:56 ubuntu plymouth[1011]: [./plymouth.c:1132] main:no need to wait
Mar 06 04:19:56 ubuntu gdm3[1016]: [./ply-boot-client.c:183] ply_boot_client_connect:could not connect to /org/freedesktop/plymouthd: Connection refused
Mar 06 04:19:56 ubuntu gdm3[1016]: [./ply-boot-client.c:184] ply_boot_client_connect:trying old fallback path /ply-boot-protocol
Mar 06 04:19:56 ubuntu gdm3[1016]: [./ply-boot-client.c:190] ply_boot_client_connect:could not connect to /ply-boot-protocol: Connection refused
Mar 06 04:19:56 ubuntu gdm3[1016]: [./plymouth.c:1121] main:daemon not running
Mar 06 04:19:56 ubuntu gdm3[1016]: [./plymouth.c:1124] main:ping failed
***********

[Nish Aravamudan (nacc)]

I just rebooted again and without hitting any keys, it did come up to the greeter without issue.

[Nish Aravamudan (nacc)]

But if I plug in my usb-c dongle, it immediately freezes and the fans start to spin. Unplugging the dongle has no effect. Suggestions for debugging?

[Daniel van Vugt (vanvugt)]

dino99,

Given the large number of bugs we're dealing with it would be safer for you to log your own bug. Often two people with similar symptoms turn out to have different bugs.

[Daniel van Vugt (vanvugt)]

Nish,

To figure the problem out you will need to be logged in already while it's happening(!), so..

1. Log into a VT (Ctrl+Alt+F4) or install openssh-server and log in from a separate machine.
2. Run 'top' to find the ID of the spinning process.
3. Run:
   kill -ABRT <PID-of-spinning-process>
4. Wait a while for crash files to be written.
5. Look in /var/crash for crash files and run:
   ubuntu-bug /var/crash/YOURFILE.crash
6. Add a comment here telling us the ID of the new bug.

[Nish Aravamudan (nacc)]

Hi Daniel,

On Mon, Mar 5, 2018 at 9:56 PM, Daniel van Vugt
<email address hidden> wrote:
> Nish,
>
> To figure the problem out you will need to be logged in already while
> it's happening(!), so..

Yeah, tricky when the machine physically seems to be hung (no
touchpad, no responsiveness to keyboard)

> 1. Log into a VT (Ctrl+Alt+F4) or install openssh-server and log in from a separate machine.
> 2. Run 'top' to find the ID of the spinning process.
> 3. Run:
> kill -ABRT <PID-of-spinning-process>
> 4. Wait a while for crash files to be written.
> 5. Look in /var/crash for crash files and run:
> ubuntu-bug /var/crash/YOURFILE.crash
> 6. Add a comment here telling us the ID of the new bug.

Thanks for the info!

I just was wondering, as the responsiveness of the desktop feels very
different, and it does seem like I'm now on an Xwayland session, even
though I didn't change anything. I wonder if it's Wayland that's
actually crashing?

gdm 2795 0.0 0.0 190684 5496 tty1 Ssl+ Mar05 0:00
/usr/lib/gdm3/gdm-wayland-session gnome-session --autostart
/usr/share/gdm/greeter/autostart
gdm 2878 0.0 0.3 563888 55076 tty1 Sl+ Mar05 0:00
/usr/bin/Xwayland :1024 -rootless -terminate -accessx -core -listen 4
-listen 5 -displayfd 6
nacc 3428 0.0 0.0 190684 5408 tty2 Ssl+ Mar05 0:00
/usr/lib/gdm3/gdm-wayland-session gnome-session --session=gnome
nacc 3502 0.0 0.3 565704 56056 tty2 Sl+ Mar05 0:02
/usr/bin/Xwayland :0 -rootless -terminate -accessx -core -listen 4
-listen 5 -displayfd 6

[Nish Aravamudan (nacc)]

I edited /etc/gdm3/custom.conf and put WaylandEnable=false back in (I had it enabled before to test). Greeter came right up on reboot and my external monitor works again.

What is curious is that my session choice in both cases was/is Gnome on Xorg. So is it possible there's some change in the greeter's behavior? As to using wayland or not.

[Daniel van Vugt (vanvugt)]

Wayland is not a program, so "Wayland" can't crash. Wayland is only a protocol for talking to apps that is supported by the Gnome Shell 'eglnative' backend inside the 'mutter' project. This issue is further confused by the incorrect wording "Ubuntu on Wayland" on the login screen. Actually it's not running "on Wayland" at all...

That all said, yes the eglnative backend in mutter, which provides Wayland app support, can crash for its own reasons.

The greeter will default to eglnative ("Wayland") mode, so if you find disabling that works around the bug (switching to Xorg instead) then great. However this bug will stay incomplete until we have some sort of stack trace of a crash, ideally a .crash file.

[Launchpad Janitor (janitor)]

[Expired for xorg (Ubuntu) because there has been no activity for 60 days.]

[Launchpad Janitor (janitor)]

[Expired for gnome-shell (Ubuntu) because there has been no activity for 60 days.]

[Launchpad Janitor (janitor)]

[Expired for gdm3 (Ubuntu) because there has been no activity for 60 days.]