AW: [PATCH] drm/fdinfo: Protect against driver unbind

[Tvrtko Ursulin]

+ Thomas, AFAICT you are handling drm-misc-fixes this round - are you 
okay to take this patch with Christian's rb?

Regards,

Tvrtko

On 23/04/2025 13:57, Christian König wrote:
> On 4/22/25 17:10, Tvrtko Ursulin wrote:
>>
>> On 22/04/2025 10:20, Koenig, Christian wrote:
>>> [AMD Official Use Only - AMD Internal Distribution Only]
>>>
>>> Reviewed-by: Christian König <christian.koenig at amd.com>
>>
>> Thanks!
>>
>> I could also add:
>>
>> Fixes: 3f09a0cd4ea3 ("drm: Add common fdinfo helper")
>> Cc: <stable at vger.kernel.org> # v6.5+
>>
>> With a disclaimer that the problem predates the common helper. Not sure if it is worth it for such an edge case.
>>
>> I was planning to merge to drm-misc-next, but if I add the stable tag it would be drm-misc-fixes right?
> 
> Yeah even without the CC:stable tag that is clearly something for the -fixes branch I would say.
> 
> Regards,
> Christian.
> 
> 
>>
>> Regards,
>>
>> Tvrtko
>>
>>> ________________________________________
>>> Von: Tvrtko Ursulin <tvrtko.ursulin at igalia.com>
>>> Gesendet: Freitag, 18. April 2025 18:25
>>> An: dri-devel at lists.freedesktop.org
>>> Cc: kernel-dev at igalia.com; Tvrtko Ursulin; Koenig, Christian; Lucas De Marchi; Rodrigo Vivi; Umesh Nerlige Ramappa
>>> Betreff: [PATCH] drm/fdinfo: Protect against driver unbind
>>>
>>> If we unbind a driver from the PCI device with an active DRM client,
>>> subsequent read of the fdinfo data associated with the file descriptor in
>>> question will not end well.
>>>
>>> Protect the path with a drm_dev_enter/exit() pair.
>>>
>>> Signed-off-by: Tvrtko Ursulin <tvrtko.ursulin at igalia.com>
>>> Cc: Christian König <christian.koenig at amd.com>
>>> Cc: Lucas De Marchi <lucas.demarchi at intel.com>
>>> Cc: Rodrigo Vivi <rodrigo.vivi at intel.com>
>>> Cc: Umesh Nerlige Ramappa <umesh.nerlige.ramappa at intel.com>
>>> ---
>>>    drivers/gpu/drm/drm_file.c | 6 ++++++
>>>    1 file changed, 6 insertions(+)
>>>
>>> diff --git a/drivers/gpu/drm/drm_file.c b/drivers/gpu/drm/drm_file.c
>>> index c299cd94d3f7..cf2463090d3a 100644
>>> --- a/drivers/gpu/drm/drm_file.c
>>> +++ b/drivers/gpu/drm/drm_file.c
>>> @@ -964,6 +964,10 @@ void drm_show_fdinfo(struct seq_file *m, struct file *f)
>>>           struct drm_file *file = f->private_data;
>>>           struct drm_device *dev = file->minor->dev;
>>>           struct drm_printer p = drm_seq_file_printer(m);
>>> +       int idx;
>>> +
>>> +       if (!drm_dev_enter(dev, &idx))
>>> +               return;
>>>
>>>           drm_printf(&p, "drm-driver:\t%s\n", dev->driver->name);
>>>           drm_printf(&p, "drm-client-id:\t%llu\n", file->client_id);
>>> @@ -983,6 +987,8 @@ void drm_show_fdinfo(struct seq_file *m, struct file *f)
>>>
>>>           if (dev->driver->show_fdinfo)
>>>                   dev->driver->show_fdinfo(&p, file);
>>> +
>>> +       drm_dev_exit(idx);
>>>    }
>>>    EXPORT_SYMBOL(drm_show_fdinfo);
>>>
>>> -- 
>>> 2.48.0
>>>
>>
>