From: Sudeep Holla <sudeep.holla@arm.com>
To: linux-kernel@vger.kernel.org, linux-arm-kernel@lists.infradead.org
Cc: Sudeep Holla <sudeep.holla@arm.com>,
Thomas Gleixner <tglx@linutronix.de>
Subject: [PATCH 3/3] clockevents: warn if cpu_all_mask is used for cpumask while registering new device
Date: Wed, 11 Jul 2018 12:24:24 +0100 [thread overview]
Message-ID: <1531308264-24220-3-git-send-email-sudeep.holla@arm.com> (raw)
In-Reply-To: <1531308264-24220-1-git-send-email-sudeep.holla@arm.com>
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 boot hang with forever loop in clockevents_notify_released as both
were being selected as preferred.
In order to prevent such issues in future, let's warn if any clockevent
drivers 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.
Cc: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Sudeep Holla <sudeep.holla@arm.com>
---
kernel/time/clockevents.c | 6 ++++++
1 file changed, 6 insertions(+)
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);
--
2.7.4
next prev parent reply other threads:[~2018-07-11 11:24 UTC|newest]
Thread overview: 10+ messages / expand[flat|nested] mbox.gz Atom feed top
2018-07-11 11:24 [PATCH 1/3] clocksource: drivers: set clockevent device cpumask to cpu_possible_mask Sudeep Holla
2018-07-11 11:24 ` [PATCH 2/3] tick: broadcast-hrtimer: use cpu_possible_mask for ce_broadcast_hrtimer Sudeep Holla
2018-08-02 12:58 ` [tip:timers/core] tick/broadcast-hrtimer: Use " tip-bot for Sudeep Holla
2018-07-11 11:24 ` Sudeep Holla [this message]
2018-08-02 12:39 ` [PATCH 3/3] clockevents: warn if cpu_all_mask is used for cpumask while registering new device Sudeep Holla
2018-08-02 12:58 ` [tip:timers/core] clockevents: Warn if cpu_all_mask is used as cpumask tip-bot for Sudeep Holla
2018-07-11 11:36 ` [PATCH 1/3] clocksource: drivers: set clockevent device cpumask to cpu_possible_mask Daniel Lezcano
2018-07-11 13:42 ` Sudeep Holla
2018-07-11 16:38 ` Daniel Lezcano
2018-07-13 22:45 ` Thomas Gleixner
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