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

Pull timer updates from Ingo Molnar:
 "This cycle had the following changes:

   - Timer tracing improvements (Anna-Maria Gleixner)

   - Continued tasklet reduction work: remove the hrtimer_tasklet
     (Thomas Gleixner)

   - Fix CPU hotplug remove race in the tick-broadcast mask handling
     code (Thomas Gleixner)

   - Force upper bound for setting CLOCK_REALTIME, to fix ABI
     inconsistencies with handling values that are close to the maximum
     supported and the vagueness of when uptime related wraparound might
     occur. Make the consistent maximum the year 2232 across all
     relevant ABIs and APIs. (Thomas Gleixner)

   - various cleanups and smaller fixes"

* 'timers-core-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
  tick: Fix typos in comments
  tick/broadcast: Fix warning about undefined tick_broadcast_oneshot_offline()
  timekeeping: Force upper bound for setting CLOCK_REALTIME
  timer/trace: Improve timer tracing
  timer/trace: Replace deprecated vsprintf pointer extension %pf by %ps
  timer: Move trace point to get proper index
  tick/sched: Update tick_sched struct documentation
  tick: Remove outgoing CPU from broadcast masks
  timekeeping: Consistently use unsigned int for seqcount snapshot
  softirq: Remove tasklet_hrtimer
  xfrm: Replace hrtimer tasklet with softirq hrtimer
  mac80211_hwsim: Replace hrtimer tasklet with softirq hrtimer

1 files changed, 21 insertions, 0 deletions

diff --git a/include/linux/time64.h b/include/linux/time64.h
index f38d382ffec1..a620ee610b9f 100644
--- a/include/linux/time64.h
+++ b/include/linux/time64.h
@@ -33,6 +33,17 @@ struct itimerspec64 {
 #define KTIME_MAX			((s64)~((u64)1 << 63))
 #define KTIME_SEC_MAX			(KTIME_MAX / NSEC_PER_SEC)
 
+/*
+ * Limits for settimeofday():
+ *
+ * To prevent setting the time close to the wraparound point time setting
+ * is limited so a reasonable uptime can be accomodated. Uptime of 30 years
+ * should be really sufficient, which means the cutoff is 2232. At that
+ * point the cutoff is just a small part of the larger problem.
+ */
+#define TIME_UPTIME_SEC_MAX		(30LL * 365 * 24 *3600)
+#define TIME_SETTOD_SEC_MAX		(KTIME_SEC_MAX - TIME_UPTIME_SEC_MAX)
+
 static inline int timespec64_equal(const struct timespec64 *a,
 				   const struct timespec64 *b)
 {
@@ -100,6 +111,16 @@ static inline bool timespec64_valid_strict(const struct timespec64 *ts)
 	return true;
 }
 
+static inline bool timespec64_valid_settod(const struct timespec64 *ts)
+{
+	if (!timespec64_valid(ts))
+		return false;
+	/* Disallow values which cause overflow issues vs. CLOCK_REALTIME */
+	if ((unsigned long long)ts->tv_sec >= TIME_SETTOD_SEC_MAX)
+		return false;
+	return true;
+}
+
 /**
  * timespec64_to_ns - Convert timespec64 to nanoseconds
  * @ts:		pointer to the timespec64 variable to be converted