From: Viresh Kumar <viresh.kumar@linaro.org>
To: Preeti U Murthy <preeti@linux.vnet.ibm.com>
Cc: rjw@rjwysocki.net, ego@linux.vnet.ibm.com, paulus@samba.org,
linux-kernel@vger.kernel.org, shilpa.bhat@linux.vnet.ibm.com,
linux-pm@vger.kernel.org
Subject: Re: [RFC PATCH] cpufreq/hotplug: Fix cpu-hotplug cpufreq race conditions
Date: Tue, 2 Jun 2015 11:57:24 +0530 [thread overview]
Message-ID: <20150602062724.GF10443@linux> (raw)
In-Reply-To: <556D4B32.3000407@linux.vnet.ibm.com>
On 02-06-15, 11:50, Preeti U Murthy wrote:
> CPU0 CPU1
>
> store* store*
>
> lock(policy 1) lock(policy 2)
> cpufreq_set_policy() cpufreq_set_policy()
> EXIT() :
> dbs-data->usage_count--
>
> INIT() EXIT()
When will INIT() follow EXIT() in set_policy() for the same governor ?
Maybe not, and so this sequence is hypothetical ?
> dbs_data exists dbs_data->usage_count -- = 0
> kfree(dbs_data)
> dbs-data->usage_count++
> *NULL dereference*
But even if this happens, it should be handled with
dbs_data->mutex_lock, which is used at other places already.
--
viresh
next prev parent reply other threads:[~2015-06-02 6:27 UTC|newest]
Thread overview: 11+ messages / expand[flat|nested] mbox.gz Atom feed top
2015-06-01 6:40 [RFC PATCH] cpufreq/hotplug: Fix cpu-hotplug cpufreq race conditions Preeti U Murthy
2015-06-01 7:19 ` Viresh Kumar
2015-06-01 7:55 ` Preeti U Murthy
2015-06-02 5:31 ` Preeti U Murthy
2015-06-02 5:39 ` Viresh Kumar
2015-06-02 6:03 ` Preeti U Murthy
2015-06-02 6:11 ` Viresh Kumar
2015-06-02 6:20 ` Preeti U Murthy
2015-06-02 6:27 ` Viresh Kumar [this message]
2015-06-02 6:56 ` Preeti U Murthy
2015-06-02 7:07 ` Viresh Kumar
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