Merge branch 'timers-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip

Pull cputime fix from Ingo Molnar:
 "This fixes a longer-standing cputime accounting bug that Stanislaw
  Gruszka finally managed to track down"

* 'timers-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
  sched/cputime: Do not scale when utime == 0

1 files changed, 11 insertions, 8 deletions

diff --git a/kernel/sched/cputime.c b/kernel/sched/cputime.c
index ace34f9..9994791 100644
--- a/kernel/sched/cputime.c
+++ b/kernel/sched/cputime.c
@@ -551,10 +551,7 @@ static void cputime_adjust(struct task_cputime *curr,
 			   struct cputime *prev,
 			   cputime_t *ut, cputime_t *st)
 {
-	cputime_t rtime, stime, utime, total;
-
-	stime = curr->stime;
-	total = stime + curr->utime;
+	cputime_t rtime, stime, utime;
 
 	/*
 	 * Tick based cputime accounting depend on random scheduling
@@ -576,13 +573,19 @@ static void cputime_adjust(struct task_cputime *curr,
 	if (prev->stime + prev->utime >= rtime)
 		goto out;
 
-	if (total) {
+	stime = curr->stime;
+	utime = curr->utime;
+
+	if (utime == 0) {
+		stime = rtime;
+	} else if (stime == 0) {
+		utime = rtime;
+	} else {
+		cputime_t total = stime + utime;
+
 		stime = scale_stime((__force u64)stime,
 				    (__force u64)rtime, (__force u64)total);
 		utime = rtime - stime;
-	} else {
-		stime = rtime;
-		utime = 0;
 	}
 
 	/*