[hrtimer] Enforce resolution as lower limit of intervals

Roman Zippel pointed out that the missing lower limit of intervals
leads to an accounting error in the overrun count. Enforce the lower
limit of intervals to resolution in the timer forwarding code.

Signed-off-by: Thomas Gleixner <tglx@linutronix.de>

1 files changed, 4 insertions, 1 deletions

diff --git a/kernel/hrtimer.c b/kernel/hrtimer.c
index 76d759ce6231..04ccab099e84 100644
--- a/kernel/hrtimer.c
+++ b/kernel/hrtimer.c
@@ -275,7 +275,7 @@ void unlock_hrtimer_base(const struct hrtimer *timer, unsigned long *flags)
  * The number of overruns is added to the overrun field.
  */
 unsigned long
-hrtimer_forward(struct hrtimer *timer, const ktime_t interval)
+hrtimer_forward(struct hrtimer *timer, ktime_t interval)
 {
         unsigned long orun = 1;
         ktime_t delta, now;
@@ -287,6 +287,9 @@ hrtimer_forward(struct hrtimer *timer, const ktime_t interval)
         if (delta.tv64 < 0)
                 return 0;
 
+        if (interval.tv64 < timer->base->resolution.tv64)
+                interval.tv64 = timer->base->resolution.tv64;
+
         if (unlikely(delta.tv64 >= interval.tv64)) {
                 nsec_t incr = ktime_to_ns(interval);