From: Nikita Zhandarovich n.zhandarovich@fintech.ru

Since 'adev->dm.dc' in amdgpu_dm_fini() might turn out to be NULL before the call to dc_enable_dmub_notifications(), check beforehand to ensure there will not be a possible NULL-ptr-deref there.

Also, since commit 1e88eb1b2c25 ("drm/amd/display: Drop CONFIG_DRM_AMD_DC_HDCP") there are two separate checks for NULL in 'adev->dm.dc' before dc_deinit_callbacks() and dc_dmub_srv_destroy(). Clean up by combining them all under one 'if'.

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

Fixes: 81927e2808be ("drm/amd/display: Support for DMUB AUX") Signed-off-by: Nikita Zhandarovich n.zhandarovich@fintech.ru Signed-off-by: Alex Deucher alexander.deucher@amd.com Signed-off-by: Jianqi Ren jianqi.ren.cn@windriver.com --- drivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm.c | 14 +++++++------- 1 file changed, 7 insertions(+), 7 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 8dc0f70df24f..7b4d44dcb343 100644 --- a/drivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm.c +++ b/drivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm.c @@ -1882,14 +1882,14 @@ static void amdgpu_dm_fini(struct amdgpu_device *adev) dc_deinit_callbacks(adev->dm.dc); #endif

- if (adev->dm.dc) + if (adev->dm.dc) { dc_dmub_srv_destroy(&adev->dm.dc->ctx->dmub_srv); - - if (dc_enable_dmub_notifications(adev->dm.dc)) { - kfree(adev->dm.dmub_notify); - adev->dm.dmub_notify = NULL; - destroy_workqueue(adev->dm.delayed_hpd_wq); - adev->dm.delayed_hpd_wq = NULL; + if (dc_enable_dmub_notifications(adev->dm.dc)) { + kfree(adev->dm.dmub_notify); + adev->dm.dmub_notify = NULL; + destroy_workqueue(adev->dm.delayed_hpd_wq); + adev->dm.delayed_hpd_wq = NULL; + } }

if (adev->dm.dmub_bo)