Merge branch 'timers-fixes-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip

* 'timers-fixes-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip:
  time: Fix accumulation bug triggered by long delay.
  posix-cpu-timers: Reset expire cache when no timer is running
  timer stats: Fix del_timer_sync() and try_to_del_timer_sync()
  clockevents: Sanitize min_delta_ns adjustment and prevent overflows

6 files changed, 54 insertions, 17 deletions

diff --git a/include/linux/clockchips.h b/include/linux/clockchips.h
index 0cf725bdd2a1..fc53492b6ad7 100644
--- a/include/linux/clockchips.h
+++ b/include/linux/clockchips.h
@@ -73,6 +73,7 @@ enum clock_event_nofitiers {
  * @list:               list head for the management code
  * @mode:               operating mode assigned by the management code
  * @next_event:         local storage for the next event in oneshot mode
+ * @retries:            number of forced programming retries
  */
 struct clock_event_device {
         const char              *name;
@@ -93,6 +94,7 @@ struct clock_event_device {
         struct list_head        list;
         enum clock_event_mode   mode;
         ktime_t                 next_event;
+        unsigned long           retries;
 };
 
 /*
diff --git a/kernel/posix-cpu-timers.c b/kernel/posix-cpu-timers.c
index 1a22dfd42df9..bc7704b3a443 100644
--- a/kernel/posix-cpu-timers.c
+++ b/kernel/posix-cpu-timers.c
@@ -1061,9 +1061,9 @@ static void check_thread_timers(struct task_struct *tsk,
         }
 }
 
-static void stop_process_timers(struct task_struct *tsk)
+static void stop_process_timers(struct signal_struct *sig)
 {
-        struct thread_group_cputimer *cputimer = &tsk->signal->cputimer;
+        struct thread_group_cputimer *cputimer = &sig->cputimer;
         unsigned long flags;
 
         if (!cputimer->running)
@@ -1072,6 +1072,10 @@ static void stop_process_timers(struct task_struct *tsk)
         spin_lock_irqsave(&cputimer->lock, flags);
         cputimer->running = 0;
         spin_unlock_irqrestore(&cputimer->lock, flags);
+
+        sig->cputime_expires.prof_exp = cputime_zero;
+        sig->cputime_expires.virt_exp = cputime_zero;
+        sig->cputime_expires.sched_exp = 0;
 }
 
 static u32 onecputick;
@@ -1133,7 +1137,7 @@ static void check_process_timers(struct task_struct *tsk,
             list_empty(&timers[CPUCLOCK_VIRT]) &&
             cputime_eq(sig->it[CPUCLOCK_VIRT].expires, cputime_zero) &&
             list_empty(&timers[CPUCLOCK_SCHED])) {
-                stop_process_timers(tsk);
+                stop_process_timers(sig);
                 return;
         }
 
diff --git a/kernel/time/tick-oneshot.c b/kernel/time/tick-oneshot.c
index 0a8a213016f0..aada0e52680a 100644
--- a/kernel/time/tick-oneshot.c
+++ b/kernel/time/tick-oneshot.c
@@ -22,6 +22,29 @@
 
 #include "tick-internal.h"
 
+/* Limit min_delta to a jiffie */
+#define MIN_DELTA_LIMIT         (NSEC_PER_SEC / HZ)
+
+static int tick_increase_min_delta(struct clock_event_device *dev)
+{
+        /* Nothing to do if we already reached the limit */
+        if (dev->min_delta_ns >= MIN_DELTA_LIMIT)
+                return -ETIME;
+
+        if (dev->min_delta_ns < 5000)
+                dev->min_delta_ns = 5000;
+        else
+                dev->min_delta_ns += dev->min_delta_ns >> 1;
+
+        if (dev->min_delta_ns > MIN_DELTA_LIMIT)
+                dev->min_delta_ns = MIN_DELTA_LIMIT;
+
+        printk(KERN_WARNING "CE: %s increased min_delta_ns to %llu nsec\n",
+               dev->name ? dev->name : "?",
+               (unsigned long long) dev->min_delta_ns);
+        return 0;
+}
+
 /**
  * tick_program_event internal worker function
  */
@@ -37,23 +60,28 @@ int tick_dev_program_event(struct clock_event_device *dev, ktime_t expires,
                 if (!ret || !force)
                         return ret;
 
+                dev->retries++;
                 /*
-                 * We tried 2 times to program the device with the given
-                 * min_delta_ns. If that's not working then we double it
+                 * We tried 3 times to program the device with the given
+                 * min_delta_ns. If that's not working then we increase it
                  * and emit a warning.
                  */
                 if (++i > 2) {
                         /* Increase the min. delta and try again */
-                        if (!dev->min_delta_ns)
-                                dev->min_delta_ns = 5000;
-                        else
-                                dev->min_delta_ns += dev->min_delta_ns >> 1;
-
-                        printk(KERN_WARNING
-                               "CE: %s increasing min_delta_ns to %llu nsec\n",
-                               dev->name ? dev->name : "?",
-                               (unsigned long long) dev->min_delta_ns << 1);
-
+                        if (tick_increase_min_delta(dev)) {
+                                /*
+                                 * Get out of the loop if min_delta_ns
+                                 * hit the limit already. That's
+                                 * better than staying here forever.
+                                 *
+                                 * We clear next_event so we have a
+                                 * chance that the box survives.
+                                 */
+                                printk(KERN_WARNING
+                                       "CE: Reprogramming failure. Giving up\n");
+                                dev->next_event.tv64 = KTIME_MAX;
+                                return -ETIME;
+                        }
                         i = 0;
                 }
 
diff --git a/kernel/time/timekeeping.c b/kernel/time/timekeeping.c
index 16736379a9ca..39f6177fafac 100644
--- a/kernel/time/timekeeping.c
+++ b/kernel/time/timekeeping.c
@@ -818,7 +818,8 @@ void update_wall_time(void)
         shift = min(shift, maxshift);
         while (offset >= timekeeper.cycle_interval) {
                 offset = logarithmic_accumulation(offset, shift);
-                shift--;
+                if(offset < timekeeper.cycle_interval<<shift)
+                        shift--;
         }
 
         /* correct the clock when NTP error is too big */
diff --git a/kernel/time/timer_list.c b/kernel/time/timer_list.c
index bdfb8dd1050c..1a4a7dd78777 100644
--- a/kernel/time/timer_list.c
+++ b/kernel/time/timer_list.c
@@ -228,6 +228,7 @@ print_tickdevice(struct seq_file *m, struct tick_device *td, int cpu)
         SEQ_printf(m, " event_handler:  ");
         print_name_offset(m, dev->event_handler);
         SEQ_printf(m, "\n");
+        SEQ_printf(m, " retries:        %lu\n", dev->retries);
 }
 
 static void timer_list_show_tickdevices(struct seq_file *m)
@@ -257,7 +258,7 @@ static int timer_list_show(struct seq_file *m, void *v)
         u64 now = ktime_to_ns(ktime_get());
         int cpu;
 
-        SEQ_printf(m, "Timer List Version: v0.5\n");
+        SEQ_printf(m, "Timer List Version: v0.6\n");
         SEQ_printf(m, "HRTIMER_MAX_CLOCK_BASES: %d\n", HRTIMER_MAX_CLOCK_BASES);
         SEQ_printf(m, "now at %Ld nsecs\n", (unsigned long long)now);
 
diff --git a/kernel/timer.c b/kernel/timer.c
index c61a7949387f..fc965eae0e87 100644
--- a/kernel/timer.c
+++ b/kernel/timer.c
@@ -880,6 +880,7 @@ int try_to_del_timer_sync(struct timer_list *timer)
         if (base->running_timer == timer)
                 goto out;
 
+        timer_stats_timer_clear_start_info(timer);
         ret = 0;
         if (timer_pending(timer)) {
                 detach_timer(timer, 1);