Re: [patch 10/13] cpufreq/sh: Replace racy task affinity logic

From: Viresh Kumar <viresh.kumar@linaro.org>
To: Thomas Gleixner <tglx@linutronix.de>
Cc: LKML <linux-kernel@vger.kernel.org>,
	Peter Zijlstra <peterz@infradead.org>,
	Ingo Molnar <mingo@kernel.org>,
	Sebastian Siewior <bigeasy@linutronix.de>,
	Benjamin Herrenschmidt <benh@kernel.crashing.org>,
	"David S. Miller" <davem@davemloft.net>,
	Fenghua Yu <fenghua.yu@intel.com>,
	Herbert Xu <herbert@gondor.apana.org.au>,
	Lai Jiangshan <jiangshanlai@gmail.com>,
	Len Brown <lenb@kernel.org>,
	Michael Ellerman <mpe@ellerman.id.au>,
	"Rafael J. Wysocki" <rjw@rjwysocki.net>,
	Tejun Heo <tj@kernel.org>, Tony Luck <tony.luck@intel.com>,
	linux-pm@vger.kernel.org
Subject: Re: [patch 10/13] cpufreq/sh: Replace racy task affinity logic
Date: Thu, 13 Apr 2017 08:16:36 +0530	[thread overview]
Message-ID: <20170413024636.GJ5910@vireshk-i7> (raw)
In-Reply-To: <20170412201042.958216363@linutronix.de>

On 12-04-17, 22:07, Thomas Gleixner wrote:
> The target() callback must run on the affected cpu. This is achieved by
> temporarily setting the affinity of the calling thread to the requested CPU
> and reset it to the original affinity afterwards.
> 
> That's racy vs. concurrent affinity settings for that thread resulting in
> code executing on the wrong CPU.
> 
> Replace it by work_on_cpu(). All call pathes which invoke the callbacks are
> already protected against CPU hotplug.
> 
> Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
> Cc: "Rafael J. Wysocki" <rjw@rjwysocki.net>
> Cc: Viresh Kumar <viresh.kumar@linaro.org>
> Cc: linux-pm@vger.kernel.org
> ---
>  drivers/cpufreq/sh-cpufreq.c |   45 +++++++++++++++++++++++++------------------
>  1 file changed, 27 insertions(+), 18 deletions(-)

Acked-by: Viresh Kumar <viresh.kumar@linaro.org>

-- 
viresh