linux-kernel - Re: [PATCH 3/5] perf/arm-ccn: Fix CPU hotplug race avoidance

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Date:   Tue, 5 Feb 2019 11:38:10 +0000
From:   Suzuki K Poulose <suzuki.poulose@....com>
To:     robin.murphy@....com, will.deacon@....com, mark.rutland@....com
Cc:     linux-kernel@...r.kernel.org, linux-arm-kernel@...ts.infradead.org,
        peterz@...radead.org, tglx@...utronix.de, bigeasy@...utronix.de
Subject: Re: [PATCH 3/5] perf/arm-ccn: Fix CPU hotplug race avoidance



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@....com>

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