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Subject: Re: [PATCH 3/3] coresight: ultrasoc-smb: fix uninitialized before use
 buf_hw_base
To:     Yicong Yang <yangyicong@huawei.com>
References: <20231012094706.21565-1-hejunhao3@huawei.com>
 <20231012094706.21565-4-hejunhao3@huawei.com>
 <fe5af067-d2f4-7967-e75b-272b00e6275f@huawei.com>
CC:     <james.clark@arm.com>, <suzuki.poulose@arm.com>,
        <yangyicong@hisilicon.com>, <coresight@lists.linaro.org>,
        <linux-arm-kernel@lists.infradead.org>,
        <linux-kernel@vger.kernel.org>, <linuxarm@huawei.com>,
        <jonathan.cameron@huawei.com>, <prime.zeng@hisilicon.com>
From:   hejunhao <hejunhao3@huawei.com>
Message-ID: <3e67ba5a-4022-0089-1ede-46f73ad70afa@huawei.com>
Date:   Thu, 19 Oct 2023 21:08:08 +0800
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On 2023/10/19 10:34, Yicong Yang wrote:
> On 2023/10/12 17:47, Junhao He wrote:
>> In smb_reset_buffer, the sdb->buf_hw_base variable is uninitialized
>> before use, which initializes it in smb_init_data_buffer. And the SMB
>> regiester are set in smb_config_inport.
>> So move the call after smb_config_inport.
>>
>> Fixes: 06f5c2926aaa ("drivers/coresight: Add UltraSoc System Memory Buffer driver")
>>
>> Signed-off-by: Junhao He <hejunhao3@huawei.com>
>> ---
>>   drivers/hwtracing/coresight/ultrasoc-smb.c | 2 +-
>>   1 file changed, 1 insertion(+), 1 deletion(-)
>>
>> diff --git a/drivers/hwtracing/coresight/ultrasoc-smb.c b/drivers/hwtracing/coresight/ultrasoc-smb.c
>> index e78edc3480ce..21ba473786e5 100644
>> --- a/drivers/hwtracing/coresight/ultrasoc-smb.c
>> +++ b/drivers/hwtracing/coresight/ultrasoc-smb.c
>> @@ -475,7 +475,6 @@ static int smb_init_data_buffer(struct platform_device *pdev,
>>   static void smb_init_hw(struct smb_drv_data *drvdata)
>>   {
>>   	smb_disable_hw(drvdata);
>> -	smb_reset_buffer(drvdata);
>>   
>>   	writel(SMB_LB_CFG_LO_DEFAULT, drvdata->base + SMB_LB_CFG_LO_REG);
>>   	writel(SMB_LB_CFG_HI_DEFAULT, drvdata->base + SMB_LB_CFG_HI_REG);
>> @@ -597,6 +596,7 @@ static int smb_probe(struct platform_device *pdev)
>>   	}
>>   
>>   	platform_set_drvdata(pdev, drvdata);
>> +	smb_reset_buffer(drvdata);
> Shouldn't we reset the buffer before registering the sink? Otherwise it'll
> be possible for user to access an unreset one.
>

Hi Yicong,

Thanks for the comments!

The code after the smb_register_sink() function also needs to moved.
I will fix all in next version.

Best regards,
Junhao.