--- src/sys/bus/cam/scsi/scsi_pass.c	2007/11/18 17:53:01	1.23
+++ src/sys/bus/cam/scsi/scsi_pass.c	2007/11/21 21:28:41	1.24
@@ -225,6 +225,8 @@ passasync(void *callback_arg, u_int32_t
 		cam_status status;
  
 		cgd = (struct ccb_getdev *)arg;
+		if (cgd == NULL)
+			break;
 
 		/*
 		 * Allocate a peripheral instance for