drm/amd/display: Add NULL check for stream before dereference in 'dm_vupdate_high_irq'

Add a NULL check for acrtc->dm_irq_params.stream before
accessing its members.

Fixes below:
drivers/gpu/drm/amd/amdgpu/../display/amdgpu_dm/amdgpu_dm.c:623
dm_vupdate_high_irq() warn: variable dereferenced before check
'acrtc->dm_irq_params.stream' (see line 615)

614	if (vrr_active) {
615		bool replay_en = acrtc->dm_irq_params.stream->link->replay_settings.replay_feature_enabled;
				 ^^^^^^^^^^^^^^^^^^^^^^^^^^^
616		bool psr_en = acrtc->dm_irq_params.stream->link->psr_settings.psr_feature_enabled;
			      ^^^^^^^^^^^^^^^^^^^^^^^^^^^ New dereferences

617		bool fs_active_var_en = acrtc->dm_irq_params.freesync_config.state
618			== VRR_STATE_ACTIVE_VARIABLE;
619
620		amdgpu_dm_crtc_handle_vblank(acrtc);
621
622		/* BTR processing for pre-DCE12 ASICs */
623		if (acrtc->dm_irq_params.stream &&
		    ^^^^^^^^^^^^^^^^^^^^^^^^^^^ But the existing code assumed it could be NULL. Someone is wrong.

624		    adev->family < AMDGPU_FAMILY_AI) {
625			spin_lock_irqsave(&adev_to_drm(adev)->event_lock, flags);

Fixes: 6d31602a9f57 ("drm/amd/display: more liberal vmin/vmax update for freesync")
Reported-by: Dan Carpenter <dan.carpenter@linaro.org>
Cc: Alex Hung <alex.hung@amd.com>
Cc: Aurabindo Pillai <aurabindo.pillai@amd.com>
Cc: Roman Li <roman.li@amd.com>
Cc: ChiaHsuan Chung <chiahsuan.chung@amd.com>
Cc: Harry Wentland <harry.wentland@amd.com>
Cc: Ray Wu <ray.wu@amd.com>
Cc: Daniel Wheeler <daniel.wheeler@amd.com>
Cc: Nicholas Kazlauskas <nicholas.kazlauskas@amd.com>
Signed-off-by: Srinivasan Shanmugam <srinivasan.shanmugam@amd.com>
Reviewed-by: Aurabindo Pillai <aurabindo.pillai@amd.com>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>

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 31ea57edeb45c9808dda43402412be90d6722930..c0d31c26850d27e603370e05dc6e140b1c4e9a4e 100644 (file)
--- a/drivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm.c
+++ b/drivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm.c
@@ -611,7 +611,7 @@ static void dm_vupdate_high_irq(void *interrupt_params)
                 * page-flip completion events that have been queued to us
                 * if a pageflip happened inside front-porch.
                 */
-               if (vrr_active) {
+               if (vrr_active && acrtc->dm_irq_params.stream) {
                        bool replay_en = acrtc->dm_irq_params.stream->link->replay_settings.replay_feature_enabled;
                        bool psr_en = acrtc->dm_irq_params.stream->link->psr_settings.psr_feature_enabled;
                        bool fs_active_var_en = acrtc->dm_irq_params.freesync_config.state
@@ -620,8 +620,7 @@ static void dm_vupdate_high_irq(void *interrupt_params)
                        amdgpu_dm_crtc_handle_vblank(acrtc);
 
                        /* BTR processing for pre-DCE12 ASICs */
-                       if (acrtc->dm_irq_params.stream &&
-                           adev->family < AMDGPU_FAMILY_AI) {
+                       if (adev->family < AMDGPU_FAMILY_AI) {
                                spin_lock_irqsave(&adev_to_drm(adev)->event_lock, flags);
                                mod_freesync_handle_v_update(
                                    adev->dm.freesync_module,