From 3b1f4d5e47b361002490d2297b344ce34dae3d55 Mon Sep 17 00:00:00 2001 From: Evgenii Burenchev Date: Mon, 29 Jun 2026 15:59:01 -0500 Subject: [PATCH] drm/amd/display: Fix dangling pointer in connector reset function amdgpu_dm_connector_funcs_reset() frees the old state before allocating a new one. If kzalloc() fails, the function returns without updating the state pointer, leaving a dangling pointer to already freed memory. Fix this by allocating the new state first. On allocation failure, the old state remains untouched and the function safely returns. Found by Linux Verification Center (linuxtesting.org) with SVACE. Fixes: e7b07ceef2a6 ("drm/amd/display: Merge amdgpu_dm_crtc and dm_crtc_state") Signed-off-by: Evgenii Burenchev Reviewed-by: Mario Limonciello (AMD) Link: https://patch.msgid.link/20260629090435.9729-5-evg28bur@yandex.ru [adjust for movement around current amd-staging-drm-next] Signed-off-by: Mario Limonciello Signed-off-by: Alex Deucher --- .../display/amdgpu_dm/amdgpu_dm_connector.c | 39 ++++++++++--------- 1 file changed, 20 insertions(+), 19 deletions(-) diff --git a/drivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm_connector.c b/drivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm_connector.c index d4720c5576ce..40688d35bde6 100644 --- a/drivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm_connector.c +++ b/drivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm_connector.c @@ -1786,33 +1786,34 @@ static void amdgpu_dm_connector_destroy(struct drm_connector *connector) void amdgpu_dm_connector_funcs_reset(struct drm_connector *connector) { - struct dm_connector_state *state = + struct dm_connector_state *old_state = to_dm_connector_state(connector->state); + struct dm_connector_state *state; + + state = kzalloc_obj(*state); + if (!state) + return; if (connector->state) __drm_atomic_helper_connector_destroy_state(connector->state); - kfree(state); + kfree(old_state); - state = kzalloc_obj(*state); + __drm_atomic_helper_connector_reset(connector, &state->base); - if (state) { - state->scaling = RMX_OFF; - state->underscan_enable = false; - state->underscan_hborder = 0; - state->underscan_vborder = 0; - state->base.max_requested_bpc = 8; - state->vcpi_slots = 0; - state->pbn = 0; + state->scaling = RMX_OFF; + state->underscan_enable = false; + state->underscan_hborder = 0; + state->underscan_vborder = 0; + state->base.max_requested_bpc = 8; + state->vcpi_slots = 0; + state->pbn = 0; - if (connector->connector_type == DRM_MODE_CONNECTOR_eDP) { - if (amdgpu_dm_abm_level <= 0) - state->abm_level = ABM_LEVEL_IMMEDIATE_DISABLE; - else - state->abm_level = amdgpu_dm_abm_level; - } - - __drm_atomic_helper_connector_reset(connector, &state->base); + if (connector->connector_type == DRM_MODE_CONNECTOR_eDP) { + if (amdgpu_dm_abm_level <= 0) + state->abm_level = ABM_LEVEL_IMMEDIATE_DISABLE; + else + state->abm_level = amdgpu_dm_abm_level; } } EXPORT_IF_KUNIT(amdgpu_dm_connector_funcs_reset);