drm/amdgpu/mmhub2.3: add bounds checking for cid

commit a54403a upstream.

The value should never exceed the array size as those
are the only values the hardware is expected to return,
but add checks anyway.

Reviewed-by: Benjamin Cheng <benjamin.cheng@amd.com>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>
(cherry picked from commit 89cd90375c19fb45138990b70e9f4ba4806f05c4)
Cc: stable@vger.kernel.org
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

Author: alexdeucher

drivers/gpu/drm/amd/amdgpu/mmhub_v2_3.c

@@ -94,7 +94,8 @@ mmhub_v2_3_print_l2_protection_fault_status(struct amdgpu_device *adev,
 	case IP_VERSION(2, 3, 0):
 	case IP_VERSION(2, 4, 0):
 	case IP_VERSION(2, 4, 1):
-		mmhub_cid = mmhub_client_ids_vangogh[cid][rw];
+		mmhub_cid = cid < ARRAY_SIZE(mmhub_client_ids_vangogh) ?
+			mmhub_client_ids_vangogh[cid][rw] : NULL;
 		break;
 	default:
 		mmhub_cid = NULL;