[PATCH v2] amdgpu: nbio_v7_4: Add pointer check

[Alex Deucher]

On Fri, Nov 18, 2022 at 9:11 AM Denis Arefev <arefev at swemel.ru> wrote:
>
> Return value of a function 'amdgpu_ras_find_obj' is dereferenced
> at nbio_v7_4.c:325 without checking for null
>
> Found by Linux Verification Center (linuxtesting.org) with SVACE.
>
> Signed-off-by: Denis Arefev <arefev at swemel.ru>
> ---
>  drivers/gpu/drm/amd/amdgpu/nbio_v7_4.c | 3 +++
>  1 file changed, 3 insertions(+)
>
> diff --git a/drivers/gpu/drm/amd/amdgpu/nbio_v7_4.c b/drivers/gpu/drm/amd/amdgpu/nbio_v7_4.c
> index eadc9526d33f..0f2ac99de864 100644
> --- a/drivers/gpu/drm/amd/amdgpu/nbio_v7_4.c
> +++ b/drivers/gpu/drm/amd/amdgpu/nbio_v7_4.c
> @@ -304,6 +304,9 @@ static void nbio_v7_4_handle_ras_controller_intr_no_bifring(struct amdgpu_device
>         struct ras_err_data err_data = {0, 0, 0, NULL};
>         struct amdgpu_ras *ras = amdgpu_ras_get_context(adev);
>
> +       if (!obj)
> +               return;
>

I don't think we could ever get here with a NULL obj.  This is part of
the interrupt handler for NBIO RAS, so the interrupt would never be
enabled in the first place if the obj didn't exist.

Alex

>         bif_doorbell_intr_cntl = RREG32_SOC15(NBIO, 0, mmBIF_DOORBELL_INT_CNTL);
>         if (REG_GET_FIELD(bif_doorbell_intr_cntl,
>                 BIF_DOORBELL_INT_CNTL, RAS_CNTLR_INTERRUPT_STATUS)) {
> --
> 2.25.1
>