Merge branch 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/s390/linux into akpm

Pull s390 regression fix from Martin Schwidefsky:
 "The recent fix for the s390 sched_clock() function uncovered yet
  another bug in s390_next_ktime which causes an endless loop in KVM.
  This regression should be fixed before v3.8.

  I keep the fingers crossed that this is the last one for v3.8."

* 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/s390/linux:
  s390/timer: avoid overflow when programming clock comparator

1 files changed, 3 insertions, 0 deletions

diff --git a/arch/s390/kernel/time.c b/arch/s390/kernel/time.c
index a5f4f5a1d24b..0aa98db8a80d 100644
--- a/arch/s390/kernel/time.c
+++ b/arch/s390/kernel/time.c
@@ -120,6 +120,9 @@ static int s390_next_ktime(ktime_t expires,
         nsecs = ktime_to_ns(ktime_add(timespec_to_ktime(ts), expires));
         do_div(nsecs, 125);
         S390_lowcore.clock_comparator = sched_clock_base_cc + (nsecs << 9);
+        /* Program the maximum value if we have an overflow (== year 2042) */
+        if (unlikely(S390_lowcore.clock_comparator < sched_clock_base_cc))
+                S390_lowcore.clock_comparator = -1ULL;
         set_clock_comparator(S390_lowcore.clock_comparator);
         return 0;
 }