If the only process in the pgrp is in the middle of exiting, it might

not have any threads left.  Treat that the same as an empty pgrp.

encountered by and ok deraadt@

diff --git a/sys/kern/tty.c b/sys/kern/tty.c
index 2fb04ad..41b42ba 100644 (file)
--- a/sys/kern/tty.c
+++ b/sys/kern/tty.c
@@ -1,4 +1,4 @@
-/*     $OpenBSD: tty.c,v 1.111 2014/07/12 18:43:32 tedu Exp $  */
+/*     $OpenBSD: tty.c,v 1.112 2014/07/13 14:56:56 guenther Exp $      */
 /*     $NetBSD: tty.c,v 1.68.4.2 1996/06/06 16:04:52 thorpej Exp $     */
 
 /*-
@@ -2149,7 +2149,7 @@ ttyinfo(struct tty *tp)
        else if (tp->t_pgrp == NULL)
                ttyprintf(tp, "no foreground process group\n");
        else if ((pr = LIST_FIRST(&tp->t_pgrp->pg_members)) == NULL)
-               ttyprintf(tp, "empty foreground process group\n");
+empty:         ttyprintf(tp, "empty foreground process group\n");
        else {
                const char *state;
                fixpt_t pctcpu, pctcpu2;
@@ -2219,6 +2219,8 @@ update_pickpr:
                 * Otherwise take the newest thread
                 */
                pick = p = TAILQ_FIRST(&pickpr->ps_threads);
+               if (p == NULL)
+                       goto empty;
                run = p->p_stat == SRUN || p->p_stat == SONPROC;
                pctcpu = p->p_pctcpu;
                while ((p = TAILQ_NEXT(p, p_thr_link)) != NULL) {