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authorLinus Torvalds <torvalds@linux-foundation.org>2020-12-27 20:03:41 +0300
committerLinus Torvalds <torvalds@linux-foundation.org>2020-12-27 20:03:41 +0300
commit2eeefc60ad70ffb7a5daf9f47aef5b1ebd1f39ad (patch)
tree0ebab4a8e90013c61459efb074e80dddc924b571
parent3b80dee70eaa5f9a120db058c30cc8e63c443571 (diff)
parentf6f5cd840ae782680c5e94048c72420e4e6857f9 (diff)
downloadlinux-2eeefc60ad70ffb7a5daf9f47aef5b1ebd1f39ad.tar.xz
Merge tag 'timers-urgent-2020-12-27' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip
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
-rw-r--r--kernel/time/Kconfig2
-rw-r--r--kernel/time/tick-common.c10
-rw-r--r--kernel/time/tick-sched.c7
3 files changed, 4 insertions, 15 deletions
diff --git a/kernel/time/Kconfig b/kernel/time/Kconfig
index 9a41848b6ebb..83e158d016ba 100644
--- 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 a03764df5366..9d3a22510bab 100644
--- 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 030282994b3e..e10a4af88737 100644
--- 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))