linux-kernel - Re: [PATCH] cpufreq: Fix policy->freq_table is NULL in __cpufreq_driver

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Message-ID: <20230330035715.hckcbf4xpsi5cwhz@vireshk-i7>
Date:   Thu, 30 Mar 2023 09:27:15 +0530
From:   Viresh Kumar <viresh.kumar@...aro.org>
To:     Yajun Deng <yajun.deng@...ux.dev>
Cc:     "Rafael J. Wysocki" <rafael@...nel.org>, linux-pm@...r.kernel.org,
        linux-kernel@...r.kernel.org
Subject: Re: [PATCH] cpufreq: Fix policy->freq_table is NULL in
 __cpufreq_driver_target()

On 30-03-23, 01:39, Yajun Deng wrote:
> March 29, 2023 10:21 PM, "Rafael J. Wysocki" <rafael@...nel.org> wrote:
> 
> > On Wed, Mar 29, 2023 at 3:36 PM Yajun Deng <yajun.deng@...ux.dev> wrote:
> > 
> >> __resolve_freq() may be return target_freq if policy->freq_table is
> >> NULL. In this case, it should return -EINVAL before __target_index().
> > 
> > Even so, __target_index() itself doesn't dereference freq_table
> > AFAICS, so arguably the driver should be prepared to deal with a NULL
> > freq_table which comes from it after all.
> > 
> 
> But there is a statement 'unsigned int newfreq = policy->freq_table[index].frequency;'
> in __target_index(), if driver doesn't provide freq_table, __target_index()
> will fault before the driver itself.

Driver must provide a freq table here.

-- 
viresh