linux-kernel - Re: [PATCH] cpufreq: Fix NULL reference crash while accessing policy->governor

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Message-ID: <20160128021553.GC3935@vireshk>
Date:	Thu, 28 Jan 2016 07:45:53 +0530
From:	Viresh Kumar <viresh.kumar@...aro.org>
To:	"Rafael J. Wysocki" <rjw@...ysocki.net>
Cc:	linaro-kernel@...ts.linaro.org, linux-pm@...r.kernel.org,
	"# v4 . 2+" <stable@...r.kernel.org>,
	Juri Lelli <juri.lelli@....com>,
	open list <linux-kernel@...r.kernel.org>
Subject: Re: [PATCH] cpufreq: Fix NULL reference crash while accessing
 policy->governor_data

On 27-01-16, 23:54, Rafael J. Wysocki wrote:
> So I've applied this, but I'm not sure it is sufficient yet.

At least, this solves the crash Juri was hitting on a multi cluster
box.

> Have you double checked whether or not stuff cannot be reordered by
> the CPU and/or the compiler and no additional memory barriers are needed?

I don't think CPU will reorder things before a function call. It can
reorder lines, which CPU thinks aren't related but it can't assume the
same in this case. We have tons of code like this.

@Juri: What do you say? 

-- 
viresh