4.16-stable review patch. If anyone has any objections, please let me know. ------------------ From: Peter Zijlstra <peterz@xxxxxxxxxxxxx> 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@xxxxxxxxxxxxx> Signed-off-by: Thomas Gleixner <tglx@xxxxxxxxxxxxx> Reviewed-by: Rafael J. Wysocki <rafael.j.wysocki@xxxxxxxxx> Cc: len.brown@xxxxxxxxx Cc: rjw@xxxxxxxxxxxxx Cc: diego.viola@xxxxxxxxx Cc: rui.zhang@xxxxxxxxx Cc: stable@xxxxxxxxxxxxxxx Link: https://lkml.kernel.org/r/20180430100344.594904898@xxxxxxxxxxxxx Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx> --- 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); }
