From 8950d2445635ef8789ae96d30feb4b868dc8d1ce Mon Sep 17 00:00:00 2001
From: Brian Feldman <green@FreeBSD.org>
Date: Fri, 28 Jan 2000 20:40:29 +0000
Subject: [PATCH] Fix a bug that could crash the system if you press ^T while a
 slower system is slowed down and in the right spot (a race condition in
 fork()).

The "previous time" fields have moved from pstat to proc.  Anything which
uses KVM needs to be recompiled with a new libkvm/headers.

A couple wacky u_quad_t's in struct proc are now u_int64_t (the same, but
according to lack of 'quad's in proc.h and usage in kern_resource.c).
This will have no effect on code.

This has been make-world-and-installed-new-kernel-which-works-fine-tested.

Reviewed by:	bde (previous version)
---
 sys/kern/kern_resource.c | 33 ++++++++++++++++-----------------
 sys/sys/proc.h           | 11 +++++++----
 sys/sys/resourcevar.h    |  3 ---
 3 files changed, 23 insertions(+), 24 deletions(-)

diff --git a/sys/kern/kern_resource.c b/sys/kern/kern_resource.c
index 495175ed935..0307369bb07 100644
--- a/sys/kern/kern_resource.c
+++ b/sys/kern/kern_resource.c
@@ -528,7 +528,7 @@ calcru(p, up, sp, ip)
 			tu += (tv.tv_usec - switchtime.tv_usec) +
 			    (tv.tv_sec - switchtime.tv_sec) * (int64_t)1000000;
 	}
-	ptu = p->p_stats->p_uu + p->p_stats->p_su + p->p_stats->p_iu;
+	ptu = p->p_uu + p->p_su + p->p_iu;
 	if (tu < ptu || (int64_t)tu < 0) {
 		/* XXX no %qd in kernel.  Truncate. */
 		printf("calcru: negative time of %ld usec for pid %d (%s)\n",
@@ -542,30 +542,29 @@ calcru(p, up, sp, ip)
 	iu = tu - uu - su;
 
 	/* Enforce monotonicity. */
-	if (uu < p->p_stats->p_uu || su < p->p_stats->p_su ||
-	    iu < p->p_stats->p_iu) {
-		if (uu < p->p_stats->p_uu)
-			uu = p->p_stats->p_uu;
-		else if (uu + p->p_stats->p_su + p->p_stats->p_iu > tu)
-			uu = tu - p->p_stats->p_su - p->p_stats->p_iu;
+	if (uu < p->p_uu || su < p->p_su || iu < p->p_iu) {
+		if (uu < p->p_uu)
+			uu = p->p_uu;
+		else if (uu + p->p_su + p->p_iu > tu)
+			uu = tu - p->p_su - p->p_iu;
 		if (st == 0)
-			su = p->p_stats->p_su;
+			su = p->p_su;
 		else {
 			su = ((tu - uu) * st) / (st + it);
-			if (su < p->p_stats->p_su)
-				su = p->p_stats->p_su;
-			else if (uu + su + p->p_stats->p_iu > tu)
-				su = tu - uu - p->p_stats->p_iu;
+			if (su < p->p_su)
+				su = p->p_su;
+			else if (uu + su + p->p_iu > tu)
+				su = tu - uu - p->p_iu;
 		}
-		KASSERT(uu + su + p->p_stats->p_iu <= tu,
+		KASSERT(uu + su + p->p_iu <= tu,
 		    ("calcru: monotonisation botch 1"));
 		iu = tu - uu - su;
-		KASSERT(iu >= p->p_stats->p_iu,
+		KASSERT(iu >= p->p_iu,
 		    ("calcru: monotonisation botch 2"));
 	}
-	p->p_stats->p_uu = uu;
-	p->p_stats->p_su = su;
-	p->p_stats->p_iu = iu;
+	p->p_uu = uu;
+	p->p_su = su;
+	p->p_iu = iu;
 
 	up->tv_sec = uu / 1000000;
 	up->tv_usec = uu % 1000000;
diff --git a/sys/sys/proc.h b/sys/sys/proc.h
index f6af6d91b66..4c2eead9f77 100644
--- a/sys/sys/proc.h
+++ b/sys/sys/proc.h
@@ -172,10 +172,13 @@ struct	proc {
 	u_int	p_slptime;	 /* Time since last blocked. */
 
 	struct	itimerval p_realtimer;	/* Alarm timer. */
-	u_int64_t	p_runtime;	/* Real time in microsec. */
-	u_quad_t p_uticks;		/* Statclock hits in user mode. */
-	u_quad_t p_sticks;		/* Statclock hits in system mode. */
-	u_quad_t p_iticks;		/* Statclock hits processing intr. */
+	u_int64_t p_runtime;		/* Real time in microsec. */
+	u_int64_t p_uu;			/* Previous user time in microsec. */
+	u_int64_t p_su;			/* Previous system time in microsec. */
+	u_int64_t p_iu;			/* Previous interrupt time in usec. */
+	u_int64_t p_uticks;		/* Statclock hits in user mode. */
+	u_int64_t p_sticks;		/* Statclock hits in system mode. */
+	u_int64_t p_iticks;		/* Statclock hits processing intr. */
 
 	int	p_traceflag;		/* Kernel trace points. */
 	struct	vnode *p_tracep;	/* Trace to vnode. */
diff --git a/sys/sys/resourcevar.h b/sys/sys/resourcevar.h
index 92ed5bf687b..75a8f53994b 100644
--- a/sys/sys/resourcevar.h
+++ b/sys/sys/resourcevar.h
@@ -47,9 +47,6 @@ struct pstats {
 #define	pstat_startzero	p_ru
 	struct	rusage p_ru;		/* stats for this proc */
 	struct	rusage p_cru;		/* sum of stats for reaped children */
-	u_int64_t p_uu;			/* previous user time (us) */
-	u_int64_t p_su;			/* previous system time (us) */
-	u_int64_t p_iu;			/* previous interrupt time (us) */
 #define	pstat_endzero	pstat_startcopy
 
 #define	pstat_startcopy	p_timer