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Message-ID: <955f881c-7731-a337-3ff9-e58863c41976@quicinc.com>
Date:   Tue, 21 Jun 2022 10:44:15 -0700
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Subject: Re: [PATCH] drm/msm/dpu: Fix variable dereferenced before check
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From:   Abhinav Kumar <quic_abhinavk@quicinc.com>
To:     sunliming <sunliming@kylinos.cn>, <robdclark@gmail.com>,
        <dmitry.baryshkov@linaro.org>
CC:     <linux-kernel@vger.kernel.org>, <kelulanainsley@gmail.com>,
        "kernel test robot" <lkp@intel.com>,
        Dan Carpenter <dan.carpenter@oracle.com>,
        freedreno <freedreno@lists.freedesktop.org>
References: <20220621110634.368913-1-sunliming@kylinos.cn>
 <d4b882ba-b773-5271-6050-416c8f3cad4b@quicinc.com>
In-Reply-To: <d4b882ba-b773-5271-6050-416c8f3cad4b@quicinc.com>
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Copying freedreno

On 6/21/2022 10:42 AM, Abhinav Kumar wrote:
> 
> 
> On 6/21/2022 4:06 AM, sunliming wrote:
>> Fixes the following smatch warning:
>>
>> drivers/gpu/drm/msm/disp/dpu1/dpu_encoder_phys_wb.c:261
>> dpu_encoder_phys_wb_atomic_check() warn: variable dereferenced before 
>> check 'conn_state'
>>
>> Reported-by: kernel test robot <lkp@intel.com>
>> Signed-off-by: sunliming <sunliming@kylinos.cn>
> Reported-by: Dan Carpenter <dan.carpenter@oracle.com>
> Reviewed-by: Abhinav Kumar <quic_abhinavk@quicinc.com>
> 
>> ---
>>   drivers/gpu/drm/msm/disp/dpu1/dpu_encoder_phys_wb.c | 10 +++++-----
>>   1 file changed, 5 insertions(+), 5 deletions(-)
>>
>> diff --git a/drivers/gpu/drm/msm/disp/dpu1/dpu_encoder_phys_wb.c 
>> b/drivers/gpu/drm/msm/disp/dpu1/dpu_encoder_phys_wb.c
>> index 59da348ff339..0ec809ab06e7 100644
>> --- a/drivers/gpu/drm/msm/disp/dpu1/dpu_encoder_phys_wb.c
>> +++ b/drivers/gpu/drm/msm/disp/dpu1/dpu_encoder_phys_wb.c
>> @@ -252,11 +252,6 @@ static int dpu_encoder_phys_wb_atomic_check(
>>       DPU_DEBUG("[atomic_check:%d, \"%s\",%d,%d]\n",
>>               phys_enc->wb_idx, mode->name, mode->hdisplay, 
>> mode->vdisplay);
>> -    if (!conn_state->writeback_job || !conn_state->writeback_job->fb)
>> -        return 0;
>> -
>> -    fb = conn_state->writeback_job->fb;
>> -
>>       if (!conn_state || !conn_state->connector) {
>>           DPU_ERROR("invalid connector state\n");
>>           return -EINVAL;
>> @@ -267,6 +262,11 @@ static int dpu_encoder_phys_wb_atomic_check(
>>           return -EINVAL;
>>       }
>> +    if (!conn_state->writeback_job || !conn_state->writeback_job->fb)
>> +        return 0;
>> +
>> +    fb = conn_state->writeback_job->fb;
>> +
>>       DPU_DEBUG("[fb_id:%u][fb:%u,%u]\n", fb->base.id,
>>               fb->width, fb->height);