Kernel 6.5.0 with the parameter UBSAN disabled + Nvidia kernel version 535.129.03 = any kind of video flow (offline or online) is frozen at the beginning.

[Jeffrey Walton]

On Tue, Nov 7, 2023 at 4:43 PM Mario Marietto <marietto2008 at gmail.com> wrote:
>
> Hello.
>
> I’ve upgraded Ubuntu 23.04 to 23.10 recently. On my Ubuntu 23.10 I’m using kernel 6.5.0-10-generic and I’ve installed the nVidia driver version 535.129.03. (my nvidia gpu is the RTX 2080 ti ; my cpu is the intel I9). I don't have exactly the same bug of this :
>
> https://bugs.launchpad.net/ubuntu/+source/broadcom-sta/+bug/2030978?comments=all
>
> because the error in the Ubuntu bug report is for a different kernel module. But the underlying cause is probably the same.
>
> Possibly the code for the nvidia-uvm module is designed for kernel versions < 6.5, so when Ubuntu upgraded to Linux kernel 6.5, it broke some modules because of changes to UBSAN in Linux 6.5 which causes modules such as nvidia-uvm to need patches to be compatible with Linux 6.5, but either nvidia has not yet provided a version of nvidia-uvm that is compatible with Linux 6.5 or Ubuntu neglected to apply an updated version from nvidia that is compatible with Linux 6.5.
>
> I didn’t see this error on Ubuntu 23.04,maybe because it does not use the kernel 6.5 by default,but 23.10 does.
>
> I see a lot of those errors when I issue the command “dmesg” and any audio-video streamings don’t flow.
>
> At the beginning I've thought to revert the commit in 6.5 mentioned in the bug report that caused a similar problem in the broadcom-wl module:
>
> https://bugs.launchpad.net/ubuntu/+source/broadcom-sta/+bug/2030978
>
> In there it mentions the commit in 6.5.y causing the trouble:
>
> On Linux 6.5, due to commit 2d47c6956ab3 ("ubsan: Tighten UBSAN_BOUNDSon GCC"), flexible trailing arrays declared like \whatever_t foo[1];\will generate warnings when CONFIG_UBSAN & co. is enabled.
>
> The commit is here:
>
> https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/commit/?h=linux-6.5.y&id=2d47c6956ab3c8b580a59d7704aab3e2a4882b6c
>
> BUT I don't use a broadcom-wl,so I've disabled the UBSAN parameter and I've recompiled and installed kernel 6.5.0 and the nvidia-driver worked fine :
>
> https://pastebin.ubuntu.com/p/7DYsbJwNbT/
>
> (It does not work with the kernel 6.5.3. But only with 6.5.0)
>
> # uname -a
> Linux Z390-AORUS-PRO-DEST 6.5.0 #1 SMP PREEMPT_DYNAMIC Tue Nov  7 16:26:55 CET 2023 x86_64 x86_64 x86_64 GNU/Linux
>
> What's the problem now ?
>
> Even if I have been able to fix the previous error,at the moment I can't watch any video streaming,online or offline. Simply it does not flow at all. Any kind of video flow is frozen at the beginning of the stream. I took a look at the dmesg messages and I saw the ugly error that you see below. Maybe it is correlated with the problem :
>
> https://pastebin.ubuntu.com/p/SyhrqwKncZ/
>
> What to do ?
>
> UPDATE :
>
> I've discovered a very odd behavior. If I exclude the audio from the video, the video stream moves on. If I keep the audio on, the video stream freezes.
>

It is not clear to me what program is having trouble. It sounds like
you should disable GPU acceleration until the nVidia driver is
updated. Or the wrinkles are ironed out.

I'm guessing one of the problems is your web browser. In Firefox,
here's how you do it:
<https://support.mozilla.org/en-US/kb/upgrade-graphics-drivers-use-hardware-acceleration#w_turning-off-hardware-acceleration>.

Jeff