--- src/sys/bus/cam/scsi/scsi_ses.c	2007/11/18 17:53:01	1.24
+++ src/sys/bus/cam/scsi/scsi_ses.c	2007/11/21 21:28:41	1.25
@@ -279,6 +279,9 @@ sesasync(void *callback_arg, u_int32_t c
 		int inq_len;
 
 		cgd = (struct ccb_getdev *)arg;
+		if (arg == NULL) {
+			break;
+		}
 
 		inq_len = cgd->inq_data.additional_length + 4;