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References: <20230811062738.1066787-1-anshuman.khandual@arm.com>
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From:   Mike Leach <mike.leach@linaro.org>
Date:   Fri, 11 Aug 2023 09:48:02 +0100
Message-ID: <CAJ9a7Vhh95jMmfKeD40n88GXf3iYC3Hv6y1KJxEYnsKAkem7gQ@mail.gmail.com>
Subject: Re: [PATCH] coresight: etm4x: Ensure valid drvdata and clock before clk_put()
To:     Anshuman Khandual <anshuman.khandual@arm.com>
Cc:     linux-arm-kernel@lists.infradead.org, suzuki.poulose@arm.com,
        James Clark <james.clark@arm.com>, coresight@lists.linaro.org,
        linux-kernel@vger.kernel.org,
        Dan Carpenter <dan.carpenter@linaro.org>
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On Fri, 11 Aug 2023 at 07:27, Anshuman Khandual
<anshuman.khandual@arm.com> wrote:
>
> This validates 'drvdata' and 'drvdata->pclk' clock before calling clk_put()
> in etm4_remove_platform_dev(). The problem was detected using Smatch static
> checker as reported.
>
> Cc: Suzuki K Poulose <suzuki.poulose@arm.com>
> Cc: Mike Leach <mike.leach@linaro.org>
> Cc: James Clark <james.clark@arm.com>
> Cc: coresight@lists.linaro.org
> Cc: linux-arm-kernel@lists.infradead.org
> Cc: linux-kernel@vger.kernel.org
> Reported-by: Dan Carpenter <dan.carpenter@linaro.org>
> Closes: https://lists.linaro.org/archives/list/coresight@lists.linaro.org/thread/G4N6P4OXELPLLQSNU3GU2MR4LOLRXRMJ/
> Signed-off-by: Anshuman Khandual <anshuman.khandual@arm.com>
> ---
> This applies on coresight-next
>
>  drivers/hwtracing/coresight/coresight-etm4x-core.c | 2 +-
>  1 file changed, 1 insertion(+), 1 deletion(-)
>
> diff --git a/drivers/hwtracing/coresight/coresight-etm4x-core.c b/drivers/hwtracing/coresight/coresight-etm4x-core.c
> index 703b6fcbb6a5..eb412ce302cc 100644
> --- a/drivers/hwtracing/coresight/coresight-etm4x-core.c
> +++ b/drivers/hwtracing/coresight/coresight-etm4x-core.c
> @@ -2269,7 +2269,7 @@ static int __exit etm4_remove_platform_dev(struct platform_device *pdev)
>                 etm4_remove_dev(drvdata);
>         pm_runtime_disable(&pdev->dev);
>
> -       if (drvdata->pclk)
> +       if (drvdata && drvdata->pclk && !IS_ERR(drvdata->pclk))
>                 clk_put(drvdata->pclk);
>
>         return 0;
> --
> 2.25.1
>

Reviewed-by: Mike Leach <mike.leach@lnaro.org>
-- 
Mike Leach
Principal Engineer, ARM Ltd.
Manchester Design Centre. UK