[PATCH 3/3] hrtimer: fix the __hrtimer_start_range_ns() race with hrtimer_active()

[Oleg Nesterov]

Change __hrtimer_start_range_ns() to preserve ENQUEUED.
---
 kernel/time/hrtimer.c |   10 +++++-----
 1 files changed, 5 insertions(+), 5 deletions(-)

diff --git a/kernel/time/hrtimer.c b/kernel/time/hrtimer.c
index 5fceb3d..1761f96 100644
--- a/kernel/time/hrtimer.c
+++ b/kernel/time/hrtimer.c
@@ -902,8 +902,8 @@ out:
 /*
  * remove hrtimer, called with base lock held
  */
-static inline int
-remove_hrtimer(struct hrtimer *timer, struct hrtimer_clock_base *base)
+static inline int remove_hrtimer(struct hrtimer *timer,
+                       struct hrtimer_clock_base *base, bool clear_enqueued)
 {
        if (hrtimer_is_queued(timer)) {
                int reprogram;
@@ -923,7 +923,7 @@ remove_hrtimer(struct hrtimer *timer, struct 
hrtimer_clock_base *base)
                 * This preserves the CALLBACK flag,  otherwise we could move
                 * the timer base in switch_hrtimer_base.
                 */
-               __remove_hrtimer(timer, base, true, reprogram);
+               __remove_hrtimer(timer, base, clear_enqueued, reprogram);
                return 1;
        }
        return 0;
@@ -940,7 +940,7 @@ int __hrtimer_start_range_ns(struct hrtimer *timer, ktime_t 
tim,
        base = lock_hrtimer_base(timer, &flags);
 
        /* Remove an active timer from the queue: */
-       ret = remove_hrtimer(timer, base);
+       ret = remove_hrtimer(timer, base, false);
 
        if (mode & HRTIMER_MODE_REL) {
                tim = ktime_add_safe(tim, base->get_time());
@@ -1061,7 +1061,7 @@ int hrtimer_try_to_cancel(struct hrtimer *timer)
        base = lock_hrtimer_base(timer, &flags);
 
        if (!hrtimer_callback_running(timer))
-               ret = remove_hrtimer(timer, base);
+               ret = remove_hrtimer(timer, base, true);
 
        unlock_hrtimer_base(timer, &flags);
 
-- 
1.5.5.1


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