[PATCH 5.10.y 0/2] drm/amd/display: Fix potential null dereference

[PATCH 5.10.y 0/2] drm/amd/display: Fix potential null dereference

[Eslam Khafagy]

This series backports commit [52f1783ff414 ("drm/amd/display: Fix potential null dereference")]
to stable branch 5.10.y. However to apply this i had to backport commit
[3beac533b8da ("drm/amd/display: Remove redundant safeguards for dmub-srv destroy()")] first.

Igor Artemiev (1):
  drm/amd/display: Fix potential null dereference

Roman Li (1):
  drm/amd/display: Remove redundant safeguards for dmub-srv destroy()

 drivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm.c | 5 ++---
 1 file changed, 2 insertions(+), 3 deletions(-)

--
2.43.0

[PATCH 5.10.y 1/2] drm/amd/display: Remove redundant safeguards for dmub-srv destroy()

[Eslam Khafagy]

From: Roman Li <roman.li@amd.com>

[ Upstream commit 3beac533b8daa18358dabbe5059c417d192b2a93 ]

[Why]
dc_dmub_srv_destroy() has internal null-check and null assignment.
No need to duplicate them externally.

[How]
Remove redundant safeguards.

Signed-off-by: Lang Yu <Lang.Yu@amd.com>
Signed-off-by: Roman Li <roman.li@amd.com>
Reviewed-by: Nicholas Kazlauskas <Nicholas.Kazlauskas@amd.com>
Acked-by: Qingqing Zhuo <qingqing.zhuo@amd.com>
Tested-by: Daniel Wheeler <daniel.wheeler@amd.com>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>
Signed-off-by: Eslam Khafagy <eslam.medhat1993@gmail.com>
---
 drivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm.c | 6 ++----
 1 file changed, 2 insertions(+), 4 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 45420968e5f1..b698d652d41f 100644
--- a/drivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm.c
+++ b/drivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm.c
@@ -1141,10 +1141,8 @@ static void amdgpu_dm_fini(struct amdgpu_device *adev)
 	if (adev->dm.dc)
 		dc_deinit_callbacks(adev->dm.dc);
 #endif
-	if (adev->dm.dc->ctx->dmub_srv) {
-		dc_dmub_srv_destroy(&adev->dm.dc->ctx->dmub_srv);
-		adev->dm.dc->ctx->dmub_srv = NULL;
-	}
+
+	dc_dmub_srv_destroy(&adev->dm.dc->ctx->dmub_srv);
 
 	if (adev->dm.dmub_bo)
 		amdgpu_bo_free_kernel(&adev->dm.dmub_bo,
-- 
2.43.0

[PATCH 5.10.y 2/2] drm/amd/display: Fix potential null dereference

[Eslam Khafagy]

From: Igor Artemiev <Igor.A.Artemiev@mcst.ru>

[ Upstream commit 52f1783ff4146344342422c1cd94fcb4ce39b6fe ]

The adev->dm.dc pointer can be NULL and dereferenced in amdgpu_dm_fini()
without checking.

Add a NULL pointer check before calling dc_dmub_srv_destroy().

Found by Linux Verification Center (linuxtesting.org) with SVACE.

Fixes: 9a71c7d31734 ("drm/amd/display: Register DMUB service with DC")
Signed-off-by: Igor Artemiev <Igor.A.Artemiev@mcst.ru>
Signed-off-by: Hamza Mahfooz <hamza.mahfooz@amd.com>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>
Signed-off-by: Eslam Khafagy <eslam.medhat1993@gmail.com>
---
 drivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm.c | 3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)

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 b698d652d41f..0aa681939b7e 100644
--- a/drivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm.c
+++ b/drivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm.c
@@ -1142,7 +1142,8 @@ static void amdgpu_dm_fini(struct amdgpu_device *adev)
 		dc_deinit_callbacks(adev->dm.dc);
 #endif
 
-	dc_dmub_srv_destroy(&adev->dm.dc->ctx->dmub_srv);
+	if (adev->dm.dc)
+		dc_dmub_srv_destroy(&adev->dm.dc->ctx->dmub_srv);
 
 	if (adev->dm.dmub_bo)
 		amdgpu_bo_free_kernel(&adev->dm.dmub_bo,
-- 
2.43.0