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 ace34f95e200..99947919e30b 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;
         }
 
         /*