Re: [PLUG] System unbootable after Kubuntu 20.04 update and reboot

I looked at the kern.log in /var/log and it appears that nvidia IS my problem - see the log snippet, below.

Trying to boot an earlier kernel got the same kernel error as below.

I'm starting the download of Kubuntu 20.10 and I'll re-do the root drive with that and test it several times with the nvidia packages before pinning them so I don't have to go through all this @%)&$^#{ next time!

Thank you to all who offered advice and ideas - I am grateful for your help.

Eric

kern.log snippet:

[    7.230040] input: HDA NVidia HDMI/DP,pcm=3 as /devices/pci0000:00/0000:00:02.0/0000:02:00.1/sound/card1/input30
[    7.230080] input: HDA NVidia HDMI/DP,pcm=7 as /devices/pci0000:00/0000:00:02.0/0000:02:00.1/sound/card1/input31
[    7.230111] input: HDA NVidia HDMI/DP,pcm=8 as /devices/pci0000:00/0000:00:02.0/0000:02:00.1/sound/card1/input32
[    7.230140] input: HDA NVidia HDMI/DP,pcm=9 as /devices/pci0000:00/0000:00:02.0/0000:02:00.1/sound/card1/input33
[    7.230167] input: HDA NVidia HDMI/DP,pcm=10 as /devices/pci0000:00/0000:00:02.0/0000:02:00.1/sound/card1/input34
[    7.345602] usblp1: removed
[    7.523149] fbcon: Taking over console
[    7.523397] Console: switching to colour frame buffer device 240x67
[    8.361351] TCP: request_sock_TCP: Possible SYN flooding on port 60000. Sending cookies. Check SNMP counters.
[    9.377319] BUG: unable to handle page fault for address: ffff9e23e6783000
[    9.377321] #PF: supervisor write access in kernel mode
[    9.377322] #PF: error_code(0x0003) - permissions violation
[    9.377322] PGD 695601067 P4D 695601067 PUD fe8ab6063 PMD fd4d92063 PTE 8000000fe6783061
[    9.377325] Oops: 0003 [#1] SMP PTI
[    9.377326] CPU: 2 PID: 1002 Comm: Xorg Tainted: P           OE     5.4.0-74-generic #83-Ubuntu
[    9.377327] Hardware name: Hewlett-Packard HP Z440 Workstation/212B, BIOS M60 v02.34 05/18/2017
[    9.377332] RIP: 0010:memcpy_erms+0x6/0x10
[    9.377333] Code: ff 90 90 90 eb 1e 0f 1f 00 48 89 f8 48 89 d1 48 c1 e9 03 83 e2 07 f3 48 a5 89 d1 f3 a4 c3...
[    9.377334] RSP: 0018:ffffb1ebc149b7a8 EFLAGS: 00010246
[    9.377335] RAX: ffff9e23e6782ff9 RBX: ffff9e23e946a008 RCX: 0000000000000009
[    9.377335] RDX: 0000000000000010 RSI: ffff9e23e677dd47 RDI: ffff9e23e6783000
[    9.377336] RBP: ffffb1ebc149b7b0 R08: 0000000000000000 R09: ffff9e23e677dce8
[    9.377336] R10: ffff9e23dbe18008 R11: ffff9e23dbe190a0 R12: 0000000000000001
[    9.377337] R13: ffff9e23dbe18008 R14: 0000000000000000 R15: 000000000000000a
[    9.377338] FS: 00007f5d939d7a40(0000) GS:ffff9e23efb00000(0000) knlGS:0000000000000000
[    9.377338] CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
[    9.377339] CR2: ffff9e23e6783000 CR3: 0000000fddbb4001 CR4: 00000000001606e0
[    9.377339] Call Trace:
[    9.377472] ? os_mem_copy+0x10/0x20 [nvidia]
[    9.377665] _nv017678rm+0x596/0x760 [nvidia]
[    9.377667] WARNING: kernel stack frame pointer at 00000000581f7075 in Xorg:1002 has bad value 00000000ff5723ab
[    9.377668] unwind stack type:0 next_sp:0000000000000000 mask:0x2 graph_idx:0
[    9.377669] 00000000581f7075: ffff9e23e677dcf0 (0xffff9e23e677dcf0)
[    9.377854] 000000004a9e9c14: ffffffffc0d710b6 (_nv017678rm+0x596/0x760 [nvidia])
followed by a bunch of lines similar to ^^^^^^

On Thu, Jun 3, 2021 at 5:19 PM Eric Lucas <eric@lucii.org> wrote:

Today I ran apt-get dist-upgrade and it upgraded the system including some nvidia drivers.
It requested a reboot and when I rebooted it very quickly came to a black screen with a single underline cursor in the top left corner.
There is no GUI. There are no virtual consoles. Zero response to any inputs.

I booted it with a Kubuntu 21.04 live USB image. That's where I am at this moment.

I'm guessing I'll need to roll back the Nvidia update and/or rebuild something in grub.

I am not familiar with debugging and repairing a linux system at this level.
Can anyone please point me to a good guide or guides?

Also, there is something for Ubuntu called "Boot Repair" - it's one of the first suggestions on many pages.
For example see this post:
https://sourceforge.net/p/boot-repair/home/Home/

Here is the home page: https://askubuntu.com/questions/1243134/black-screen-on-startup-ubuntu-20-04

Here's how they say to get it:
sudo apt-add-repository ppa:yannubuntu/boot-repair
sudo apt update
sudo apt install -y boot-repair
boot-repair

Does anyone have experience with or advice about this?
It seems too simple and there is no clear author information so I'm suspicious.

Thanks!
Eric Lucas