Re: [PATCH] drm/vmwgfx: Fix passing partly uninitialized drm_mode_fb_cmd2 struct

[Kaiwan N Billimoria <kaiwan.billimoria@gmail.com>]

On Wed, Dec 21, 2022 at 3:45 PM Thorsten Leemhuis
<regressions@leemhuis.info> wrote:
>
> Hi, this is your Linux kernel regression tracker. The relevant code here
> is not my area of expertise, nevertheless a few questions:
Thank you
>
> On 21.12.22 03:23, Kaiwan N Billimoria wrote:
> > [REGRESSION] ?
>
> > Testing with 6.1, I find the same issue - VirtualBox VMs seem to hang
> > on boot, though the kernel has this patch applied of course...
>
> Maybe I'm missing something, but what made you assume that it's the same
> issue? The fix for that issue talked about "garbage" in some structures
> that "can cause random failures during the bringup of the fbcon." Yeah,
> maybe that ca result in a hang, but I didn't see it that thread (but
> maybe I missed)
I got an Oops when testing with VirtualBox; managed to recover it; pl
have a look:
https://gist.github.com/kaiwan/a79ad81fa63440b790724a136d16407d

The presence of the ttm module in the Oops in RIP:
 RIP: 0010:ttm_bo_move_memcpy+0x15f/0x2e0 [ttm]
and the vmwgfx module's funcs in the call stack made me think that
perhaps it's the same issue...
Am unsure, you folks will of course know better.

>
> > Am running VirtualBox 7.0.4 on an x86_64 Linux (Ubuntu 22.04.1) host;
> > the system hangs on boot with the screen
> > going blank.
>
> A bit more details would be helpful. For example: is anything printed at
> all before the system hangs? What's the last kernel that worked for you
> (and is the newer kernel using a similar build configuration)?
Earlier kernels all seem to work fine, with a similar (localmodconfig) config..
Also, as mentioned, putting 'nomodeset' in the kernel cmd line has it
work just fine, even with 6.1
>Which
> graphics adapater did you configure in VirtualBox?
VMSVGA

>
> Ciao, Thorsten (wearing his 'the Linux kernel's regression tracker' hat)
Thanks Thorsten...
-kaiwan.
>
> P.S.: As the Linux kernel's regression tracker I deal with a lot of
> reports and sometimes miss something important when writing mails like
> this. If that's the case here, don't hesitate to tell me in a public
> reply, it's in everyone's interest to set the public record straight.