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From: Viresh Kumar <viresh.kumar@linaro.org>
To: "Rafael J. Wysocki" <rjw@rjwysocki.net>
Cc: linaro-kernel@lists.linaro.org, linux-pm@vger.kernel.org,
	"# v4 . 2+" <stable@vger.kernel.org>,
	Juri Lelli <juri.lelli@arm.com>,
	open list <linux-kernel@vger.kernel.org>
Subject: Re: [PATCH] cpufreq: Fix NULL reference crash while accessing policy->governor_data
Date: Thu, 28 Jan 2016 07:45:53 +0530	[thread overview]
Message-ID: <20160128021553.GC3935@vireshk> (raw)
In-Reply-To: <3004241.yqvZmcL5vE@vostro.rjw.lan>

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

  reply	other threads:[~2016-01-28  2:15 UTC|newest]

Thread overview: 12+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2016-01-25 17:03 [PATCH] cpufreq: Fix NULL reference crash while accessing policy->governor_data Viresh Kumar
2016-01-26  9:57 ` Juri Lelli
2016-01-26 18:01   ` Juri Lelli
2016-01-26 22:49     ` Rafael J. Wysocki
2016-01-27 10:22       ` Juri Lelli
2016-01-27  3:12     ` Viresh Kumar
2016-01-27  3:10   ` Viresh Kumar
2016-01-27 10:18     ` Juri Lelli
2016-01-27 22:54 ` Rafael J. Wysocki
2016-01-28  2:15   ` Viresh Kumar [this message]
2016-01-28 10:44     ` Juri Lelli
2016-01-29  3:33     ` Rafael J. Wysocki

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