[PATCH] drm/mst: Fix NULL pointer dereference in drm_dp_add_payload_part2 (again)

From: Jeff Mahoney
Date: Fri Apr 12 2024 - 20:33:06 EST


Commit 54d217406afe (drm: use mgr->dev in drm_dbg_kms in
drm_dp_add_payload_part2) appears to have been accidentially reverted as
part of commit 5aa1dfcdf0a42 (drm/mst: Refactor the flow for payload
allocation/removement).

I've been seeing NULL pointer dereferences in drm_dp_add_payload_part2
due to state->dev being NULL in the debug message printed if the payload
allocation has failed.

This commit restores mgr->dev to avoid the Oops.

Fixes: 5aa1dfcdf0a42 ("drm/mst: Refactor the flow for payload allocation/removement")
Cc: stable@xxxxxxxxxxxxxxx
Signed-off-by: Jeff Mahoney <jeffm@xxxxxxxx>
---
drivers/gpu/drm/display/drm_dp_mst_topology.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/drivers/gpu/drm/display/drm_dp_mst_topology.c b/drivers/gpu/drm/display/drm_dp_mst_topology.c
index 03d528209426..3dc966f25c0c 100644
--- a/drivers/gpu/drm/display/drm_dp_mst_topology.c
+++ b/drivers/gpu/drm/display/drm_dp_mst_topology.c
@@ -3437,7 +3437,7 @@ int drm_dp_add_payload_part2(struct drm_dp_mst_topology_mgr *mgr,

/* Skip failed payloads */
if (payload->payload_allocation_status != DRM_DP_MST_PAYLOAD_ALLOCATION_DFP) {
- drm_dbg_kms(state->dev, "Part 1 of payload creation for %s failed, skipping part 2\n",
+ drm_dbg_kms(mgr->dev, "Part 1 of payload creation for %s failed, skipping part 2\n",
payload->port->connector->name);
return -EIO;
}
--
2.44.0