From: Sudeep Holla Date: Wed, 9 May 2018 16:02:08 +0000 (+0100) Subject: tick: Prefer a lower rating device only if it's CPU local device X-Git-Tag: Ubuntu-5.4-5.4.0-11.14~5268^2~10 X-Git-Url: https://git.proxmox.com/?a=commitdiff_plain;h=1332a90558013ae4242e3dd7934bdcdeafb06c0d;p=mirror_ubuntu-focal-kernel.git tick: Prefer a lower rating device only if it's CPU local device Checking the equality of cpumask for both new and old tick device doesn't ensure that it's CPU local device. This will cause issue if a low rating clockevent tick device is registered first followed by the registration of higher rating clockevent tick device. In such case, clockevents_released list will never get emptied as both the devices get selected as preferred one and we will loop forever in clockevents_notify_released. Signed-off-by: Sudeep Holla Signed-off-by: Thomas Gleixner Cc: Frederic Weisbecker Link: https://lkml.kernel.org/r/1525881728-4858-1-git-send-email-sudeep.holla@arm.com --- diff --git a/kernel/time/tick-common.c b/kernel/time/tick-common.c index 49edc1c4f3e6..78e598334007 100644 --- a/kernel/time/tick-common.c +++ b/kernel/time/tick-common.c @@ -277,7 +277,8 @@ static bool tick_check_preferred(struct clock_event_device *curdev, */ return !curdev || newdev->rating > curdev->rating || - !cpumask_equal(curdev->cpumask, newdev->cpumask); + (!cpumask_equal(curdev->cpumask, newdev->cpumask) && + !tick_check_percpu(curdev, newdev, smp_processor_id())); } /*