From d24cd2e8a87aede960f7f1ca450052296bab0b9c Mon Sep 17 00:00:00 2001 From: Wayne Lin Date: Tue, 11 Mar 2025 08:51:19 +0900 Subject: [PATCH] drm/amd/display: Don't refer to dc_sink in is_dsc_need_re_compute BugLink: https://bugs.launchpad.net/bugs/2101915 [ Upstream commit fcf6a49d79923a234844b8efe830a61f3f0584e4 ] [Why] When unplug one of monitors connected after mst hub, encounter null pointer dereference. It's due to dc_sink get released immediately in early_unregister() or detect_ctx(). When commit new state which directly referring to info stored in dc_sink will cause null pointer dereference. [how] Remove redundant checking condition. Relevant condition should already be covered by checking if dsc_aux is null or not. Also reset dsc_aux to NULL when the connector is disconnected. Reviewed-by: Jerry Zuo Acked-by: Zaeem Mohamed Signed-off-by: Wayne Lin Tested-by: Daniel Wheeler Signed-off-by: Alex Deucher [ Resolve minor conflicts ] Signed-off-by: Bin Lan Signed-off-by: Sasha Levin CVE-2024-44955 Signed-off-by: Koichiro Den Signed-off-by: Stefan Bader --- drivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm_mst_types.c | 4 ++++ 1 file changed, 4 insertions(+) diff --git a/drivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm_mst_types.c b/drivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm_mst_types.c index 1806f4033056..71bb17ae8c9a 100644 --- a/drivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm_mst_types.c +++ b/drivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm_mst_types.c @@ -182,6 +182,8 @@ amdgpu_dm_mst_connector_early_unregister(struct drm_connector *connector) dc_sink_release(dc_sink); aconnector->dc_sink = NULL; aconnector->edid = NULL; + aconnector->dsc_aux = NULL; + port->passthrough_aux = NULL; } aconnector->mst_status = MST_STATUS_DEFAULT; @@ -494,6 +496,8 @@ dm_dp_mst_detect(struct drm_connector *connector, dc_sink_release(aconnector->dc_sink); aconnector->dc_sink = NULL; aconnector->edid = NULL; + aconnector->dsc_aux = NULL; + port->passthrough_aux = NULL; amdgpu_dm_set_mst_status(&aconnector->mst_status, MST_REMOTE_EDID | MST_ALLOCATE_NEW_PAYLOAD | MST_CLEAR_ALLOCATED_PAYLOAD,