From fbfa9260085b5b578a049a90135e5c51928c5f7f Mon Sep 17 00:00:00 2001 From: Sudeep Holla Date: Wed, 11 Jul 2018 12:24:24 +0100 Subject: clockevents: Warn if cpu_all_mask is used as cpumask Using cpu_all_mask in clockevents cpumask may result in issues while comparing multiple clockevent devices to choose the preferred one. On one of the platforms with 2 system (i.e. non per-CPU) timers with different ratings, having cpu_all_mask for one of the device resulted in a boot hang due to a endless loop in clockevents_notify_released() as both were clocksources were selected as preferred. In order to prevent such issues in the future, warn if any clockevent driver sets cpu_all_mask as it's cpumask and just override it to use cpu_possible_mask. All the existing occurrences of cpu_all_mask are already replaced with cpu_possible_mask. Signed-off-by: Sudeep Holla Signed-off-by: Thomas Gleixner Cc: linux-arm-kernel@lists.infradead.org Link: https://lkml.kernel.org/r/1531308264-24220-3-git-send-email-sudeep.holla@arm.com --- kernel/time/clockevents.c | 6 ++++++ 1 file changed, 6 insertions(+) (limited to 'kernel/time/clockevents.c') diff --git a/kernel/time/clockevents.c b/kernel/time/clockevents.c index 16c027e9cc73..8c0e4092f661 100644 --- a/kernel/time/clockevents.c +++ b/kernel/time/clockevents.c @@ -463,6 +463,12 @@ void clockevents_register_device(struct clock_event_device *dev) dev->cpumask = cpumask_of(smp_processor_id()); } + if (dev->cpumask == cpu_all_mask) { + WARN(1, "%s cpumask == cpu_all_mask, using cpu_possible_mask instead\n", + dev->name); + dev->cpumask = cpu_possible_mask; + } + raw_spin_lock_irqsave(&clockevents_lock, flags); list_add(&dev->list, &clockevent_devices); -- cgit