[src/trunk]: src/sys/kern tc_init(): KASSERT that the timecounter hasn't prev...

[simonb <simonb%NetBSD.org@localhost>]

details:   https://anonhg.NetBSD.org/src/rev/037e905776be
branches:  trunk
changeset: 961057:037e905776be
user:      simonb <simonb%NetBSD.org@localhost>
date:      Thu Apr 08 06:06:24 2021 +0000

description:
tc_init(): KASSERT that the timecounter hasn't previously been
initialised by checking the tc_next field.  Prevents nastly endless
loops in the timecounter code.

diffstat:

 sys/kern/kern_tc.c |  7 +++++--
 1 files changed, 5 insertions(+), 2 deletions(-)

diffs (28 lines):

diff -r 93be6c8b29a7 -r 037e905776be sys/kern/kern_tc.c
--- a/sys/kern/kern_tc.c        Wed Apr 07 20:32:54 2021 +0000
+++ b/sys/kern/kern_tc.c        Thu Apr 08 06:06:24 2021 +0000
@@ -1,4 +1,4 @@
-/* $NetBSD: kern_tc.c,v 1.59 2020/05/27 09:09:50 rin Exp $ */
+/* $NetBSD: kern_tc.c,v 1.60 2021/04/08 06:06:24 simonb Exp $ */
 
 /*-
  * Copyright (c) 2008, 2009 The NetBSD Foundation, Inc.
@@ -40,7 +40,7 @@
 
 #include <sys/cdefs.h>
 /* __FBSDID("$FreeBSD: src/sys/kern/kern_tc.c,v 1.166 2005/09/19 22:16:31 andre Exp $"); */
-__KERNEL_RCSID(0, "$NetBSD: kern_tc.c,v 1.59 2020/05/27 09:09:50 rin Exp $");
+__KERNEL_RCSID(0, "$NetBSD: kern_tc.c,v 1.60 2021/04/08 06:06:24 simonb Exp $");
 
 #ifdef _KERNEL_OPT
 #include "opt_ntp.h"
@@ -551,6 +551,9 @@
 {
        u_int u;
 
+       KASSERTMSG(tc->tc_next == NULL, "timecounter %s already initialised",
+           tc->tc_name);
+
        u = tc->tc_frequency / tc->tc_counter_mask;
        /* XXX: We need some margin here, 10% is a guess */
        u *= 11;