--- a/sys/kern/kern_kthread.c
+++ b/sys/kern/kern_kthread.c
@@ -188,6 +188,7 @@
 suspend_kproc(struct thread *td, int timo)
 {
 	if (td->td_proc == NULL) {
+		lwkt_hold(td);	/* prevent exit/reuse during the protocol */
 		lwkt_gettoken(&kpsus_token);
 		/* request thread pause */
 		atomic_set_int(&td->td_mpflags, TDF_MP_STOPREQ);
@@ -199,6 +200,7 @@
 		}
 		atomic_clear_int(&td->td_mpflags, TDF_MP_STOPREQ);
 		lwkt_reltoken(&kpsus_token);
+		lwkt_rele(td);
 		return(0);
 	} else {
 		return(EINVAL);	/* not a kernel thread */