4.16-stable review patch. If anyone has any objections, please let me know.
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From: Peter Zijlstra peterz@infradead.org
commit cd2af07d823e5287cd6c91d54337348c2a873462 upstream.
When a registered clocksource gets marked unstable the watchdog_kthread will de-rate and re-select the clocksource. Ensure it also de-rates when getting called on an unregistered clocksource.
Signed-off-by: Peter Zijlstra (Intel) peterz@infradead.org Signed-off-by: Thomas Gleixner tglx@linutronix.de Reviewed-by: Rafael J. Wysocki rafael.j.wysocki@intel.com Cc: len.brown@intel.com Cc: rjw@rjwysocki.net Cc: diego.viola@gmail.com Cc: rui.zhang@intel.com Cc: stable@vger.kernel.org Link: https://lkml.kernel.org/r/20180430100344.594904898@infradead.org Signed-off-by: Greg Kroah-Hartman gregkh@linuxfoundation.org
--- kernel/time/clocksource.c | 9 ++++++++- 1 file changed, 8 insertions(+), 1 deletion(-)
--- a/kernel/time/clocksource.c +++ b/kernel/time/clocksource.c @@ -152,12 +152,19 @@ static void __clocksource_unstable(struc cs->flags &= ~(CLOCK_SOURCE_VALID_FOR_HRES | CLOCK_SOURCE_WATCHDOG); cs->flags |= CLOCK_SOURCE_UNSTABLE;
- if (list_empty(&cs->list)) + /* + * If the clocksource is registered clocksource_watchdog_kthread() will + * re-rate and re-select. + */ + if (list_empty(&cs->list)) { + cs->rating = 0; return; + }
if (cs->mark_unstable) cs->mark_unstable(cs);
+ /* kick clocksource_watchdog_kthread() */ if (finished_booting) schedule_work(&watchdog_work); }