[PATCH] drm/amdgpu: Disable irq on device before destroying it

[Alex Deucher]

On Thu, Mar 15, 2018 at 10:23 AM, Mikita Lipski <mlipski at amd.com> wrote:
>
>
> On 2018-03-15 10:15 AM, Alex Deucher wrote:
>>
>> On Thu, Mar 15, 2018 at 10:10 AM,  <mikita.lipski at amd.com> wrote:
>>>
>>> From: Mikita Lipski <mikita.lipski at amd.com>
>>>
>>> Disable irq on devices before destroying them. That prevents
>>> use-after-free memory access when unloading the driver.
>>>
>>> Signed-off-by: Mikita Lipski <mikita.lipski at amd.com>
>>> ---
>>>   drivers/gpu/drm/amd/amdgpu/amdgpu_device.c | 5 +++--
>>>   1 file changed, 3 insertions(+), 2 deletions(-)
>>>
>>> diff --git a/drivers/gpu/drm/amd/amdgpu/amdgpu_device.c
>>> b/drivers/gpu/drm/amd/amdgpu/amdgpu_device.c
>>> index b4911911..593396f 100644
>>> --- a/drivers/gpu/drm/amd/amdgpu/amdgpu_device.c
>>> +++ b/drivers/gpu/drm/amd/amdgpu/amdgpu_device.c
>>> @@ -1456,6 +1456,9 @@ static int amdgpu_device_ip_fini(struct
>>> amdgpu_device *adev)
>>>                  }
>>>          }
>>>
>>> +       /* disable all interrupts */
>>> +       amdgpu_irq_disable_all(adev);
>>> +
>>
>>
>> Any reason not to move this to the top of this function before the SMC
>> loop?
>>
>> Alex
>
>
> It can be done, but it does not seem to have any functional effect.
> The use-after-free corruption is caused by disabling DCE's irq after
> destroying it.

It would just avoid the same potential issue in the SMC module in the
future.  Either way:
Reviewed-by: Alex Deucher <alexander.deucher at amd.com>

>
> Nik
>
>
>>
>>>          for (i = adev->num_ip_blocks - 1; i >= 0; i--) {
>>>                  if (!adev->ip_blocks[i].status.hw)
>>>                          continue;
>>> @@ -1482,8 +1485,6 @@ static int amdgpu_device_ip_fini(struct
>>> amdgpu_device *adev)
>>>                  adev->ip_blocks[i].status.hw = false;
>>>          }
>>>
>>> -       /* disable all interrupts */
>>> -       amdgpu_irq_disable_all(adev);
>>>
>>>          for (i = adev->num_ip_blocks - 1; i >= 0; i--) {
>>>                  if (!adev->ip_blocks[i].status.sw)
>>> --
>>> 2.7.4
>>>
>>> _______________________________________________
>>> amd-gfx mailing list
>>> amd-gfx at lists.freedesktop.org
>>> https://lists.freedesktop.org/mailman/listinfo/amd-gfx