linux-kernel - Re: [PATCH] cpufreq: powernv: Check negative value returned by cpufreq_table_find_index

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Message-ID: <20180221100209.GP28462@vireshk-i7>
Date:   Wed, 21 Feb 2018 15:32:09 +0530
From:   Viresh Kumar <viresh.kumar@...aro.org>
To:     "Rafael J. Wysocki" <rafael@...nel.org>
Cc:     Michael Ellerman <mpe@...erman.id.au>,
        Shilpasri G Bhat <shilpa.bhat@...ux.vnet.ibm.com>,
        "Rafael J. Wysocki" <rjw@...ysocki.net>,
        Linux PM <linux-pm@...r.kernel.org>,
        Linux Kernel Mailing List <linux-kernel@...r.kernel.org>,
        linuxppc-dev <linuxppc-dev@...ts.ozlabs.org>
Subject: Re: [PATCH] cpufreq: powernv: Check negative value returned by
 cpufreq_table_find_index_dl()

On 21-02-18, 10:27, Rafael J. Wysocki wrote:
> To be precise, ->init() should fail as that's where the table is
> created.  The registration fails as a result then.
> 
> But what if the bug is that ->init() doesn't fail when it should?
> 
> I guess the core could double check the frequency table after ->init()
> if ->target_index is not NULL.
> 
> The overall point here is that if you get a negative index in
> ->fast_switch(), that's way too late anyway and we should be able to
> catch that error much earlier.

I don't want to end up doing double checking as some of it is already
done at init, but let me check on what can be done.

-- 
viresh