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Subject: Re: [PATCH 3/5] perf/arm-ccn: Fix CPU hotplug race avoidance
To:     robin.murphy@arm.com, will.deacon@arm.com, mark.rutland@arm.com
Cc:     linux-kernel@vger.kernel.org, linux-arm-kernel@lists.infradead.org,
        peterz@infradead.org, tglx@linutronix.de, bigeasy@linutronix.de
References: <cover.1549299188.git.robin.murphy@arm.com>
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From:   Suzuki K Poulose <suzuki.poulose@arm.com>
Message-ID: <a09e5e4c-f663-8797-0384-fae493ddf29d@arm.com>
Date:   Tue, 5 Feb 2019 11:38:10 +0000
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On 04/02/2019 17:09, Robin Murphy wrote:
> Like arm-cci, arm-ccn has the same issue where disabling preemption to
> avoid races between registering the PMU device and the hotplug notifier
> can lead to those operations taking mutexes in an invalid context. Fix
> it the same way by disabling hotplug instead of preemption. Since we
> only ever associate the PMU instance with a single CPU, we can also take
> the opportunity to slightly simplify the hotplug handling to track just
> that CPU number instead of a full cpumask.
> 
> Signed-off-by: Robin Murphy <robin.murphy@arm.com>

Reviewed-by: Suzuki K Poulse <suzuki.poulose@arm.com>