From ae86af8218f9798ff70696ccc00d8f840fe386e0 Mon Sep 17 00:00:00 2001
From: davidxu <davidxu@FreeBSD.org>
Date: Fri, 18 Jan 2008 13:00:28 +0000
Subject: [PATCH] Make sure reading td_runtime in critical section since thread
 may be preempted and td_runtime will be modified.

---
 sys/kern/kern_time.c | 3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)

diff --git a/sys/kern/kern_time.c b/sys/kern/kern_time.c
index 6df10fa07590..366da9da5007 100644
--- a/sys/kern/kern_time.c
+++ b/sys/kern/kern_time.c
@@ -247,8 +247,9 @@ kern_clock_gettime(struct thread *td, clockid_t clock_id, struct timespec *ats)
 		critical_enter();
 		switchtime = PCPU_GET(switchtime);
 		curtime = cpu_ticks();
+		runtime = td->td_runtime;
 		critical_exit();
-		runtime = cputick2usec(td->td_runtime + curtime - switchtime);
+		runtime = cputick2usec(runtime + curtime - switchtime);
 		ats->tv_sec = runtime / 1000000;
 		ats->tv_nsec = runtime % 1000000 * 1000;
 		break;