From 28854147323932c3a6f73aca858a7a47142f7f72 Mon Sep 17 00:00:00 2001
From: Nicholas Kazlauskas <nicholas.kazlauskas@amd.com>
Date: Thu, 9 Jun 2022 13:30:42 -0400
Subject: drm/amd/display: Guard against ddc_pin being NULL for AUX
Git-commit: bc19909f19fdc8253d720d11c948935786fbfa08
Patch-mainline: v6.0-rc1
References: jsc#PED-1166 jsc#PED-1168 jsc#PED-1170 jsc#PED-1218 jsc#PED-1220 jsc#PED-1222 jsc#PED-1223 jsc#PED-1225 jsc#PED-2849
[Why]
In the case where we don't support DMUB aux but we have DPIA links
in the configuration we might try to message AUX using the legacy
path - where DDC pin is NULL. This causes a NULL pointer dereference.
[How]
Guard against NULL DDC pin, return a failure for aux engine acquire.
Reviewed-by: Michael Strauss <Michael.Strauss@amd.com>
Acked-by: Rodrigo Siqueira <Rodrigo.Siqueira@amd.com>
Signed-off-by: Nicholas Kazlauskas <nicholas.kazlauskas@amd.com>
Tested-by: Daniel Wheeler <daniel.wheeler@amd.com>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>
Acked-by: Patrik Jakobsson <pjakobsson@suse.de>
---
drivers/gpu/drm/amd/display/dc/dce/dce_aux.c | 5 +++++
1 file changed, 5 insertions(+)
diff --git a/drivers/gpu/drm/amd/display/dc/dce/dce_aux.c b/drivers/gpu/drm/amd/display/dc/dce/dce_aux.c
index 9e39cd7b203e..49d3145ae8fb 100644
--- a/drivers/gpu/drm/amd/display/dc/dce/dce_aux.c
+++ b/drivers/gpu/drm/amd/display/dc/dce/dce_aux.c
@@ -572,6 +572,11 @@ int dce_aux_transfer_raw(struct ddc_service *ddc,
memset(&aux_req, 0, sizeof(aux_req));
+ if (ddc_pin == NULL) {
+ *operation_result = AUX_RET_ERROR_ENGINE_ACQUIRE;
+ return -1;
+ }
+
aux_engine = ddc->ctx->dc->res_pool->engines[ddc_pin->pin_data->en];
if (!acquire(aux_engine, ddc_pin)) {
*operation_result = AUX_RET_ERROR_ENGINE_ACQUIRE;
--
2.38.1