From: Juri Lelli <juri.lelli@arm.com>
To: Viresh Kumar <viresh.kumar@linaro.org>
Cc: "Rafael J. Wysocki" <rjw@rjwysocki.net>,
linaro-kernel@lists.linaro.org, linux-pm@vger.kernel.org,
"# v4 . 2+" <stable@vger.kernel.org>,
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 10:44:34 +0000 [thread overview]
Message-ID: <20160128104434.GT10898@e106622-lin> (raw)
In-Reply-To: <20160128021553.GC3935@vireshk>
On 28/01/16 07:45, Viresh Kumar wrote:
> 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?
>
Yeah, it looks good on my boxes (even though I'll run some more tests
later today). I'm not entirely sure either about the reordering, but
reordering across a function call (of a different compilation unit)
seems quite unlikely to me as well.
Best,
- Juri
next prev parent reply other threads:[~2016-01-28 10:43 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
2016-01-28 10:44 ` Juri Lelli [this message]
2016-01-29 3:33 ` Rafael J. Wysocki
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