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SubjectRe: [PATCH] drm/amd/display: Fix potential NULL pointer dereferences in amdgpu_dm_atomic_commit_tail
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On 2017-11-27 09:57 AM, Gustavo A. R. Silva wrote:
> dm_new_crtc_state->stream and disconnected_acrtc are being dereferenced
> before they are null checked, hence there is a potential null pointer
> dereference.
>
> Fix this by null checking such pointers before they are dereferenced.
>
> Addresses-Coverity-ID: 1423745 ("Dereference before null check")
> Addresses-Coverity-ID: 1423833 ("Dereference before null check")
> Fixes: e7b07ceef2a6 ("drm/amd/display: Merge amdgpu_dm_types and amdgpu_dm")
> Fixes: 54d765752467 ("drm/amd/display: Unify amdgpu_dm state variable namings.")
> Signed-off-by: Gustavo A. R. Silva <garsilva@embeddedor.com>
> ---
> drivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm.c | 12 +++++++-----
> 1 file changed, 7 insertions(+), 5 deletions(-)
>
> diff --git a/drivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm.c b/drivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm.c
> index 889ed24..3bdd137 100644
> --- a/drivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm.c
> +++ b/drivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm.c
> @@ -4190,6 +4190,9 @@ static void amdgpu_dm_atomic_commit_tail(struct drm_atomic_state *state)
>
> dm_new_crtc_state = to_dm_crtc_state(new_crtc_state);
>
> + if (!dm_new_crtc_state->stream)
> + continue;
> +
> update_stream_scaling_settings(&dm_new_con_state->base.crtc->mode,
> dm_new_con_state, (struct dc_stream_state *)dm_new_crtc_state->stream);
>
> @@ -4197,9 +4200,6 @@ static void amdgpu_dm_atomic_commit_tail(struct drm_atomic_state *state)
> WARN_ON(!status);
> WARN_ON(!status->plane_count);
>
> - if (!dm_new_crtc_state->stream)
> - continue;
> -
> /*TODO How it works with MPO ?*/
> if (!dc_commit_planes_to_stream(
> dm->dc,
> @@ -4332,9 +4332,11 @@ void dm_restore_drm_connector_state(struct drm_device *dev,
> return;
>
> disconnected_acrtc = to_amdgpu_crtc(connector->encoder->crtc);
> - acrtc_state = to_dm_crtc_state(disconnected_acrtc->base.state);
> + if (!disconnected_acrtc)
> + return;
>
> - if (!disconnected_acrtc || !acrtc_state->stream)
> + acrtc_state = to_dm_crtc_state(disconnected_acrtc->base.state);
> + if (!acrtc_state->stream)
> return;

This part is already in https://lists.freedesktop.org/archives/amd-gfx/2017-November/016389.html on its way to be merged.

The rest of the patch is
Reviewed-by: Harry Wentland <harry.wentland@amd.com>

Harry

>
> /*
>

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