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

Pull timer fixes from Thomas Gleixner:
 "Mostly small fixes for the fallout of the timekeeping overhaul in 3.6
  along with stable fixes to address an accumulation problem and missing
  sanity checks for RTC readouts and user space provided values."

* 'timers-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
  time: Avoid making adjustments if we haven't accumulated anything
  time: Avoid potential shift overflow with large shift values
  time: Fix casting issue in timekeeping_forward_now
  time: Ensure we normalize the timekeeper in tk_xtime_add
  time: Improve sanity checking of timekeeping inputs

kernel/time/timekeeping.c

@@ -115,6 +115,7 @@ static void tk_xtime_add(struct timekeeper *tk, const struct timespec *ts)
 {
 	tk->xtime_sec += ts->tv_sec;
 	tk->xtime_nsec += (u64)ts->tv_nsec << tk->shift;
+	tk_normalize_xtime(tk);
 }
 
 static void tk_set_wall_to_mono(struct timekeeper *tk, struct timespec wtm)
@@ -276,7 +277,7 @@ static void timekeeping_forward_now(struct timekeeper *tk)
 	tk->xtime_nsec += cycle_delta * tk->mult;
 
 	/* If arch requires, add in gettimeoffset() */
-	tk->xtime_nsec += arch_gettimeoffset() << tk->shift;
+	tk->xtime_nsec += (u64)arch_gettimeoffset() << tk->shift;
 
 	tk_normalize_xtime(tk);
 
@@ -427,7 +428,7 @@ int do_settimeofday(const struct timespec *tv)
 	struct timespec ts_delta, xt;
 	unsigned long flags;
 
-	if ((unsigned long)tv->tv_nsec >= NSEC_PER_SEC)
+	if (!timespec_valid(tv))
 		return -EINVAL;
 
 	write_seqlock_irqsave(&tk->lock, flags);
@@ -463,6 +464,8 @@ int timekeeping_inject_offset(struct timespec *ts)
 {
 	struct timekeeper *tk = &timekeeper;
 	unsigned long flags;
+	struct timespec tmp;
+	int ret = 0;
 
 	if ((unsigned long)ts->tv_nsec >= NSEC_PER_SEC)
 		return -EINVAL;
@@ -471,10 +474,17 @@ int timekeeping_inject_offset(struct timespec *ts)
 
 	timekeeping_forward_now(tk);
 
+	/* Make sure the proposed value is valid */
+	tmp = timespec_add(tk_xtime(tk),  *ts);
+	if (!timespec_valid(&tmp)) {
+		ret = -EINVAL;
+		goto error;
+	}
 
 	tk_xtime_add(tk, ts);
 	tk_set_wall_to_mono(tk, timespec_sub(tk->wall_to_monotonic, *ts));
 
+error: /* even if we error out, we forwarded the time, so call update */
 	timekeeping_update(tk, true);
 
 	write_sequnlock_irqrestore(&tk->lock, flags);
@@ -482,7 +492,7 @@ int timekeeping_inject_offset(struct timespec *ts)
 	/* signal hrtimers about time change */
 	clock_was_set();
 
-	return 0;
+	return ret;
 }
 EXPORT_SYMBOL(timekeeping_inject_offset);
 
@@ -649,7 +659,20 @@ void __init timekeeping_init(void)
 	struct timespec now, boot, tmp;
 
 	read_persistent_clock(&now);
+	if (!timespec_valid(&now)) {
+		pr_warn("WARNING: Persistent clock returned invalid value!\n"
+			"         Check your CMOS/BIOS settings.\n");
+		now.tv_sec = 0;
+		now.tv_nsec = 0;
+	}
+
 	read_boot_clock(&boot);
+	if (!timespec_valid(&boot)) {
+		pr_warn("WARNING: Boot clock returned invalid value!\n"
+			"         Check your CMOS/BIOS settings.\n");
+		boot.tv_sec = 0;
+		boot.tv_nsec = 0;
+	}
 
 	seqlock_init(&tk->lock);
 
@@ -1129,6 +1152,10 @@ static void update_wall_time(void)
 	offset = (clock->read(clock) - clock->cycle_last) & clock->mask;
 #endif
 
+	/* Check if there's really nothing to do */
+	if (offset < tk->cycle_interval)
+		goto out;
+
 	/*
 	 * With NO_HZ we may have to accumulate many cycle_intervals
 	 * (think "ticks") worth of time at once. To do this efficiently,
@@ -1161,9 +1188,9 @@ static void update_wall_time(void)
 	* the vsyscall implementations are converted to use xtime_nsec
 	* (shifted nanoseconds), this can be killed.
 	*/
-	remainder = tk->xtime_nsec & ((1 << tk->shift) - 1);
+	remainder = tk->xtime_nsec & ((1ULL << tk->shift) - 1);
 	tk->xtime_nsec -= remainder;
-	tk->xtime_nsec += 1 << tk->shift;
+	tk->xtime_nsec += 1ULL << tk->shift;
 	tk->ntp_error += remainder << tk->ntp_error_shift;
 
 	/*