Merge tag 'timers-urgent-2022-04-17' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip

Pull timer fixes from Thomas Gleixner:
"A small set of fixes for the timers core:

- Fix the warning condition in __run_timers() which does not take
into account that a CPU base (especially the deferrable base) never
has a timer armed on it and therefore the next_expiry value can
become stale.

- Replace a WARN_ON() in the NOHZ code with a WARN_ON_ONCE() to
prevent endless spam in dmesg.

- Remove the double star from a comment which is not meant to be in
kernel-doc format"

* tag 'timers-urgent-2022-04-17' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
tick/sched: Fix non-kernel-doc comment
tick/nohz: Use WARN_ON_ONCE() to prevent console saturation
timers: Fix warning condition in __run_timers()

kernel/time/tick-sched.c

···
 	 */
 	if (unlikely(tick_do_timer_cpu == TICK_DO_TIMER_NONE)) {
 #ifdef CONFIG_NO_HZ_FULL
-		WARN_ON(tick_nohz_full_running);
+		WARN_ON_ONCE(tick_nohz_full_running);
 #endif
 		tick_do_timer_cpu = cpu;
 	}
···
 }
 #endif
 
-/**
+/*
  * Async notification about clocksource changes
  */
 void tick_clock_notify(void)
···
 	set_bit(0, &ts->check_clocks);
 }
 
-/**
+/*
  * Check, if a change happened, which makes oneshot possible.
  *
  * Called cyclic from the hrtimer softirq (driven by the timer

kernel/time/timer.c

···
 	       time_after_eq(jiffies, base->next_expiry)) {
 		levels = collect_expired_timers(base, heads);
 		/*
-		 * The only possible reason for not finding any expired
-		 * timer at this clk is that all matching timers have been
-		 * dequeued.
+		 * The two possible reasons for not finding any expired
+		 * timer at this clk are that all matching timers have been
+		 * dequeued or no timer has been queued since
+		 * base::next_expiry was set to base::clk +
+		 * NEXT_TIMER_MAX_DELTA.
 		 */
-		WARN_ON_ONCE(!levels && !base->next_expiry_recalc);
+		WARN_ON_ONCE(!levels && !base->next_expiry_recalc
+			     && base->timers_pending);
 		base->clk++;
 		base->next_expiry = __next_timer_interrupt(base);