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References: <20230418130743.67024-1-n.zhandarovich@fintech.ru>
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From:   Ulf Hansson <ulf.hansson@linaro.org>
Date:   Mon, 8 May 2023 12:36:39 +0200
Message-ID: <CAPDyKFqC6eCMCjg4n_pRi9oJrkBfJuUT3Hpm=3C93dmU5E1muA@mail.gmail.com>
Subject: Re: [PATCH] PM: domains: fix integer overflow issues in genpd_parse_state()
To:     Nikita Zhandarovich <n.zhandarovich@fintech.ru>
Cc:     "Rafael J. Wysocki" <rafael@kernel.org>,
        Kevin Hilman <khilman@kernel.org>,
        Len Brown <len.brown@intel.com>, Pavel Machek <pavel@ucw.cz>,
        Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
        linux-pm@vger.kernel.org, linux-kernel@vger.kernel.org,
        lvc-project@linuxtesting.org
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On Tue, 18 Apr 2023 at 15:07, Nikita Zhandarovich
<n.zhandarovich@fintech.ru> wrote:
>
> Currently, while calculating residency and latency values, right
> operands may overflow if resulting values are big enough.
>
> To prevent this, albeit unlikely case, play it safe and convert
> right operands to left ones' type s64.
>
> Found by Linux Verification Center (linuxtesting.org) with static
> analysis tool SVACE.
>
> Fixes: 30f604283e05 ("PM / Domains: Allow domain power states to be read from DT")
> Signed-off-by: Nikita Zhandarovich <n.zhandarovich@fintech.ru>

Acked-by: Ulf Hansson <ulf.hansson@linaro.org>

Kind regards
Uffe

> ---
>  drivers/base/power/domain.c | 6 +++---
>  1 file changed, 3 insertions(+), 3 deletions(-)
>
> diff --git a/drivers/base/power/domain.c b/drivers/base/power/domain.c
> index 32084e38b73d..51b9d4eaab5e 100644
> --- a/drivers/base/power/domain.c
> +++ b/drivers/base/power/domain.c
> @@ -2939,10 +2939,10 @@ static int genpd_parse_state(struct genpd_power_state *genpd_state,
>
>         err = of_property_read_u32(state_node, "min-residency-us", &residency);
>         if (!err)
> -               genpd_state->residency_ns = 1000 * residency;
> +               genpd_state->residency_ns = 1000LL * residency;
>
> -       genpd_state->power_on_latency_ns = 1000 * exit_latency;
> -       genpd_state->power_off_latency_ns = 1000 * entry_latency;
> +       genpd_state->power_on_latency_ns = 1000LL * exit_latency;
> +       genpd_state->power_off_latency_ns = 1000LL * entry_latency;
>         genpd_state->fwnode = &state_node->fwnode;
>
>         return 0;
> --
> 2.25.1
>