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Re: [PATCH] cpufreq: Fix NULL reference crash while accessing policy->governor_data

From Juri Lelli <juri.lelli@arm.com>
Newsgroups linux.kernel
Subject Re: [PATCH] cpufreq: Fix NULL reference crash while accessing policy->governor_data
Date 2016-01-28 11:50 +0100
Message-ID <qVSjg-28z-19@gated-at.bofh.it> (permalink)
References <qUSOo-7cE-51@gated-at.bofh.it> <qVHeb-2ip-31@gated-at.bofh.it> <qVKlH-4HL-7@gated-at.bofh.it>
Organization linux.* mail to news gateway

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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

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Thread

Re: [PATCH] cpufreq: Fix NULL reference crash while accessing policy->governor_data "Rafael J. Wysocki" <rjw@rjwysocki.net> - 2016-01-28 00:00 +0100
  Re: [PATCH] cpufreq: Fix NULL reference crash while accessing  policy->governor_data Viresh Kumar <viresh.kumar@linaro.org> - 2016-01-28 03:20 +0100
    Re: [PATCH] cpufreq: Fix NULL reference crash while accessing  policy->governor_data Juri Lelli <juri.lelli@arm.com> - 2016-01-28 11:50 +0100
    Re: [PATCH] cpufreq: Fix NULL reference crash while accessing policy->governor_data "Rafael J. Wysocki" <rjw@rjwysocki.net> - 2016-01-29 04:40 +0100

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