WARNING: CPU: 0 PID: 8 at drivers/video/fbdev/core/fbmem.c:467 unregister_framebuffer+0x45/0x160

[Helge Deller]

On 9/3/24 11:56, V, Narasimhan wrote:
> [AMD Official Use Only - AMD Internal Distribution Only]
>
> Hi,
>
>
> ________________________________________
> From: Helge Deller <deller at gmx.de>
> Sent: Tuesday, September 3, 2024 01:48 AM
> To: V, Narasimhan; Thomas Zimmermann
> Cc: Linux Next Mailing List; Daniel Vetter; linux-fbdev at vger.kernel.org; dri-devel at lists.freedesktop.org; open list; linux at weissschuh.net; Borislav Petkov
> Subject: Re: WARNING: CPU: 0 PID: 8 at drivers/video/fbdev/core/fbmem.c:467 unregister_framebuffer+0x45/0x160
>
>> On 9/2/24 20:56, V, Narasimhan wrote:
>>> From: Thomas Zimmermann <tzimmermann at suse.de>
>>>>>> Seeing the following warning and bug on boot with linux-next-20240829
>>>>>>
>>>>>> WARNING: CPU: 0 PID: 8 at drivers/video/fbdev/core/fbmem.c:467 unregister_framebuffer+0x45/0x160
>>>>>> BUG: kernel NULL pointer dereference, address: 0000000000000000
>>>
>>>> Does it work if you revert one of these commits?
>>>
>>>>     c2fe0480cd77 ("fbdev/efifb: Use devm_register_framebuffer()")
>>>
>>>
>>> Reverting this commit fixes the issue.
>
>> Good.
>
>>>> For the latter, there might be a fix at
>>>
>>>> https://patchwork.freedesktop.org/patch/611902/?series=138008&rev=1
>
>> Current fbdev git tree and for-next series have this newer patch already.
>> I expect that the issue is already resolved with there, but it would
>> be good if you could test.
>
>> Helge
>
> The patch seems to be already into linux-next tree and the issue is no more seen with today's linux-next build.

Great.
Thanks for testing!

Helge