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References: <20230602085546.376086-1-d.dulov@aladdin.ru>
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From:   "Rafael J. Wysocki" <rafael@kernel.org>
Date:   Sun, 4 Jun 2023 18:13:30 +0200
Message-ID: <CAJZ5v0iyDvApQVjY=BopVSXZSg3tqmcYBnDQN2HORp3Oy8atEQ@mail.gmail.com>
Subject: Re: [PATCH] thermal: intel_powerclamp: Check for a possible array out
 of bounds access.
To:     Daniil Dulov <d.dulov@aladdin.ru>, Zhang Rui <rui.zhang@intel.com>,
        Srinivas Pandruvada <srinivas.pandruvada@linux.intel.com>
Cc:     Daniel Lezcano <daniel.lezcano@linaro.org>,
        Amit Kucheria <amitk@kernel.org>,
        Chen Yu <yu.c.chen@intel.com>,
        Jacob Pan <jacob.jun.pan@linux.intel.com>,
        linux-pm@vger.kernel.org, linux-kernel@vger.kernel.org,
        lvc-project@linuxtesting.org
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On Fri, Jun 2, 2023 at 11:12 AM Daniil Dulov <d.dulov@aladdin.ru> wrote:
>
> ratio may be equal to MAX_TARGET_RATIO - 1 that will result in
> out of bound access.
>
> Found by Linux Verification Center (linuxtesting.org) with SVACE.
>
> Fixes: d6d71ee4a14a ("PM: Introduce Intel PowerClamp Driver")
> Signed-off-by: Daniil Dulov <d.dulov@aladdin.ru>
> ---
>  drivers/thermal/intel/intel_powerclamp.c | 3 ++-
>  1 file changed, 2 insertions(+), 1 deletion(-)
>
> diff --git a/drivers/thermal/intel/intel_powerclamp.c b/drivers/thermal/intel/intel_powerclamp.c
> index fb04470d7d4b..9deaf2b8ccf6 100644
> --- a/drivers/thermal/intel/intel_powerclamp.c
> +++ b/drivers/thermal/intel/intel_powerclamp.c
> @@ -277,7 +277,8 @@ static unsigned int get_compensation(int ratio)
>                 comp = (cal_data[ratio].steady_comp +
>                         cal_data[ratio - 1].steady_comp +
>                         cal_data[ratio - 2].steady_comp) / 3;
> -       } else if (cal_data[ratio].confidence >= CONFIDENCE_OK &&
> +       } else if (ratio < MAX_TARGET_RATIO - 1 &&
> +               cal_data[ratio].confidence >= CONFIDENCE_OK &&
>                 cal_data[ratio - 1].confidence >= CONFIDENCE_OK &&
>                 cal_data[ratio + 1].confidence >= CONFIDENCE_OK) {
>                 comp = (cal_data[ratio].steady_comp +
> --

Rui, Srinivas, can you have a look at this, please?