From: "Srivatsa S. Bhat" <srivatsa.bhat@linux.vnet.ibm.com>
To: Viresh Kumar <viresh.kumar@linaro.org>
Cc: "Rafael J. Wysocki" <rjw@sisk.pl>,
Stephen Warren <swarren@wwwdotorg.org>,
"linux-pm@vger.kernel.org" <linux-pm@vger.kernel.org>,
"linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>,
cpufreq <cpufreq@vger.kernel.org>
Subject: Re: cpufreq_stats NULL deref on second system suspend
Date: Wed, 11 Sep 2013 16:44:37 +0530 [thread overview]
Message-ID: <5230509D.6040205@linux.vnet.ibm.com> (raw)
In-Reply-To: <CAKohpomzQ8Yzk+OU0btQM6DGm4xsY1RR9uYFrZD3ZHO-bhrwKQ@mail.gmail.com>
On 09/11/2013 04:15 PM, Viresh Kumar wrote:
> On 11 September 2013 16:14, Viresh Kumar <viresh.kumar@linaro.org> wrote:
>> But I would have solved it differently :)
>>
>> We don't really need to call update_policy_cpu() again and again
>> as we don't really need to update policy->cpu...
>>
>> Rather it would be better to just move following inside
>> cpufreq_policy_alloc():
>
> Half written mail sent :(
>
> What about moving following to cpufreq_policy_alloc():
>
> policy->cpu = cpu;
>
> ??
>
Hmm? The problem is not about merely updating the policy->cpu field; the
main issue is that the existing code was not letting the cpufreq-stats
code know that we updated the policy->cpu under the hood. It is important
for cpufreq-stats to know this because it maintains the reference to its
stats structure by associating it with the policy->cpu. So if policy->cpu
changes under the hood, it loses track of its reference. So we need to
keep that code informed about changes to policy->cpu. Thus, we need to call
update_policy_cpu() in the CPU online path (during resume). I don't see
how we can skip that.
Regards,
Srivatsa S. Bhat
next prev parent reply other threads:[~2013-09-11 11:18 UTC|newest]
Thread overview: 38+ messages / expand[flat|nested] mbox.gz Atom feed top
2013-09-09 19:22 cpufreq_stats NULL deref on second system suspend Stephen Warren
2013-09-09 20:01 ` Rafael J. Wysocki
2013-09-09 20:01 ` Stephen Warren
2013-09-09 20:24 ` Rafael J. Wysocki
2013-09-09 21:29 ` Stephen Warren
2013-09-09 23:14 ` Rafael J. Wysocki
2013-09-10 20:53 ` Stephen Warren
2013-09-10 22:34 ` Rafael J. Wysocki
2013-09-11 10:21 ` Srivatsa S. Bhat
2013-09-11 10:44 ` Viresh Kumar
2013-09-11 10:45 ` Viresh Kumar
2013-09-11 11:14 ` Srivatsa S. Bhat [this message]
2013-09-11 11:59 ` Viresh Kumar
2013-09-11 13:56 ` Srivatsa S. Bhat
2013-09-12 5:52 ` Viresh Kumar
2013-09-12 6:26 ` Srivatsa S. Bhat
2013-09-12 6:41 ` Viresh Kumar
2013-09-12 6:46 ` Srivatsa S. Bhat
2013-09-12 6:52 ` Viresh Kumar
2013-09-12 7:14 ` Srivatsa S. Bhat
2013-09-12 15:55 ` Stephen Warren
2013-09-12 17:26 ` Srivatsa S. Bhat
2013-09-13 4:26 ` Viresh Kumar
2013-09-11 11:10 ` Srivatsa S. Bhat
2013-09-11 11:15 ` Viresh Kumar
2013-09-11 11:17 ` Srivatsa S. Bhat
2013-09-11 11:41 ` Viresh Kumar
2013-09-11 11:09 ` Srivatsa S. Bhat
2013-09-11 16:05 ` Stephen Warren
2013-09-11 18:03 ` Srivatsa S. Bhat
2013-09-11 18:42 ` Srivatsa S. Bhat
2013-09-11 19:03 ` Stephen Warren
2013-09-11 19:46 ` Srivatsa S. Bhat
2013-09-11 20:07 ` Stephen Warren
2013-09-11 20:05 ` Srivatsa S. Bhat
2013-09-12 6:04 ` Viresh Kumar
2013-09-12 6:00 ` Viresh Kumar
2013-09-12 5:58 ` Viresh Kumar
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