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drm/amd/display: Fix potential NULL pointer dereferences in amdgpu_dm_atomic_commit_tail

PATCH In review Gustavo A. R. Silva 3 participants 3 messages Nov 27, 2017 – Nov 28, 2017

Subsystems (3)
DRM drivers Radeon and amdgpu DRM drivers AMD display core
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Gustavo A. R. Silva

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#0 lore raw

PATCH 1/1 drm/amd/display: Fix potential NULL pointer dereferences in amdgpu_dm_atomic_commit_tail

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 <[email protected]>
---
 drivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm.c | 12 +++++++-----
 1 file changed, 7 insertions(+), 5 deletions(-)
drivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm.c +7 -5
index 889ed24..3bdd137 100644
@@ -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;
 
 	/*
Signature · 1 line
2.7.4
maintainer Reviewed-by on v1 1/1
#1 lore raw
Quoted 41 lines · Gustavo A. R. Silva

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 <[email protected]>
---
 drivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm.c | 12 +++++++-----
 1 file changed, 7 insertions(+), 5 deletions(-)
drivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm.c +3 -3
index 889ed24..3bdd137 100644
@@ -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;

drivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm.c void dm_restore_drm_connector_state(struct drm_device *dev, · line 4340

Quoted 10 lines
drivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm.c +4 -2
 
 	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 <[email protected]>

Harry

drivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm.c void dm_restore_drm_connector_state(struct drm_device *dev, · line 4342

Quoted 3 lines
drivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm.c +0 -0
 	/*

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Reviewed-by on v1 1/1
#2 lore raw
In reply to Gustavo A. R. Silva
Reviewed-by Andrey Grodzovsky <[email protected]>

Thanks,

Andrey

Quoted 43 lines · Gustavo A. R. Silva

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 <[email protected]>
---
  drivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm.c | 12 +++++++-----
  1 file changed, 7 insertions(+), 5 deletions(-)
drivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm.c +3 -3
index 889ed24..3bdd137 100644
@@ -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);

drivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm.c void dm_restore_drm_connector_state(struct drm_device *dev, · line 4342

Quoted 10 lines
drivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm.c +4 -2
-	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;
 
  	/*

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