Merge tag 'timers-urgent-2020-12-27' of git://git.kernel.org/pub/scm/linux/kernel...

Pull timer fixes from Ingo Molnar:
 "Update/fix two CPU sanity checks in the hotplug and the boot code, and
  fix a typo in the Kconfig help text.

  [ Context: the first two commits are the result of an ongoing
    annotation+review work of (intentional) tick_do_timer_cpu() data
    races reported by KCSAN, but the annotations aren't fully cooked
    yet ]"

* tag 'timers-urgent-2020-12-27' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
  timekeeping: Fix spelling mistake in Kconfig "fullfill" -> "fulfill"
  tick/sched: Remove bogus boot "safety" check
  tick: Remove pointless cpu valid check in hotplug code

diff --git a/kernel/time/Kconfig b/kernel/time/Kconfig
index 9a41848..83e158d 100644 (file)
--- a/kernel/time/Kconfig
+++ b/kernel/time/Kconfig
@@ -141,7 +141,7 @@ config CONTEXT_TRACKING_FORCE
          dynticks working.
 
          This option stands for testing when an arch implements the
-         context tracking backend but doesn't yet fullfill all the
+         context tracking backend but doesn't yet fulfill all the
          requirements to make the full dynticks feature working.
          Without the full dynticks, there is no way to test the support
          for context tracking and the subsystems that rely on it: RCU

diff --git a/kernel/time/tick-common.c b/kernel/time/tick-common.c
index a03764d..9d3a225 100644 (file)
--- a/kernel/time/tick-common.c
+++ b/kernel/time/tick-common.c
@@ -407,17 +407,13 @@ EXPORT_SYMBOL_GPL(tick_broadcast_oneshot_control);
 /*
  * Transfer the do_timer job away from a dying cpu.
  *
- * Called with interrupts disabled. Not locking required. If
+ * Called with interrupts disabled. No locking required. If
  * tick_do_timer_cpu is owned by this cpu, nothing can change it.
  */
 void tick_handover_do_timer(void)
 {
-       if (tick_do_timer_cpu == smp_processor_id()) {
-               int cpu = cpumask_first(cpu_online_mask);
-
-               tick_do_timer_cpu = (cpu < nr_cpu_ids) ? cpu :
-                       TICK_DO_TIMER_NONE;
-       }
+       if (tick_do_timer_cpu == smp_processor_id())
+               tick_do_timer_cpu = cpumask_first(cpu_online_mask);
 }
 
 /*

diff --git a/kernel/time/tick-sched.c b/kernel/time/tick-sched.c
index 0302829..e10a4af 100644 (file)
--- a/kernel/time/tick-sched.c
+++ b/kernel/time/tick-sched.c
@@ -989,13 +989,6 @@ static bool can_stop_idle_tick(int cpu, struct tick_sched *ts)
                 */
                if (tick_do_timer_cpu == cpu)
                        return false;
-               /*
-                * Boot safety: make sure the timekeeping duty has been
-                * assigned before entering dyntick-idle mode,
-                * tick_do_timer_cpu is TICK_DO_TIMER_BOOT
-                */
-               if (unlikely(tick_do_timer_cpu == TICK_DO_TIMER_BOOT))
-                       return false;
 
                /* Should not happen for nohz-full */
                if (WARN_ON_ONCE(tick_do_timer_cpu == TICK_DO_TIMER_NONE))