Re: [PATCH 1/3] media: imx-jpeg: Enhance error handling in buffer allocation

["Ming Qian(OSS)" <ming.qian@oss.nxp.com>]

Hi Frank,

On 2025/3/27 22:35, Frank Li wrote:
> On Thu, Mar 27, 2025 at 10:37:05AM +0800, ming.qian@oss.nxp.com wrote:
>> From: Ming Qian <ming.qian@oss.nxp.com>
>>
>> In function mxc_jpeg_alloc_slot_data, driver will allocate some dma
>> buffer, but only return error if certain allocation failed.
>>
>> Without cleanup the allocation failure, the next time it will return
>> success directly, but let some buffer be uninitialized.
>> It may result in accessing a null pointer.
>>
>> Clean up if error occurs in the allocation.
>>
>> Signed-off-by: Ming Qian <ming.qian@oss.nxp.com>
> 
> Look like it is bug fix, add fixes tags

Yes, I missed it, I will add it in v2

Thanks,
Ming

> 
> Frank
>> ---
>>   .../media/platform/nxp/imx-jpeg/mxc-jpeg.c    | 47 +++++++++++--------
>>   1 file changed, 27 insertions(+), 20 deletions(-)
>>
>> diff --git a/drivers/media/platform/nxp/imx-jpeg/mxc-jpeg.c b/drivers/media/platform/nxp/imx-jpeg/mxc-jpeg.c
>> index 0e6ee997284b..12661c177f5a 100644
>> --- a/drivers/media/platform/nxp/imx-jpeg/mxc-jpeg.c
>> +++ b/drivers/media/platform/nxp/imx-jpeg/mxc-jpeg.c
>> @@ -752,6 +752,32 @@ static int mxc_get_free_slot(struct mxc_jpeg_slot_data *slot_data)
>>   	return -1;
>>   }
>>
>> +static void mxc_jpeg_free_slot_data(struct mxc_jpeg_dev *jpeg)
>> +{
>> +	/* free descriptor for decoding/encoding phase */
>> +	dma_free_coherent(jpeg->dev, sizeof(struct mxc_jpeg_desc),
>> +			  jpeg->slot_data.desc,
>> +			  jpeg->slot_data.desc_handle);
>> +	jpeg->slot_data.desc = NULL;
>> +	jpeg->slot_data.desc_handle = 0;
>> +
>> +	/* free descriptor for encoder configuration phase / decoder DHT */
>> +	dma_free_coherent(jpeg->dev, sizeof(struct mxc_jpeg_desc),
>> +			  jpeg->slot_data.cfg_desc,
>> +			  jpeg->slot_data.cfg_desc_handle);
>> +	jpeg->slot_data.cfg_desc_handle = 0;
>> +	jpeg->slot_data.cfg_desc = NULL;
>> +
>> +	/* free configuration stream */
>> +	dma_free_coherent(jpeg->dev, MXC_JPEG_MAX_CFG_STREAM,
>> +			  jpeg->slot_data.cfg_stream_vaddr,
>> +			  jpeg->slot_data.cfg_stream_handle);
>> +	jpeg->slot_data.cfg_stream_vaddr = NULL;
>> +	jpeg->slot_data.cfg_stream_handle = 0;
>> +
>> +	jpeg->slot_data.used = false;
>> +}
>> +
>>   static bool mxc_jpeg_alloc_slot_data(struct mxc_jpeg_dev *jpeg)
>>   {
>>   	struct mxc_jpeg_desc *desc;
>> @@ -794,30 +820,11 @@ static bool mxc_jpeg_alloc_slot_data(struct mxc_jpeg_dev *jpeg)
>>   	return true;
>>   err:
>>   	dev_err(jpeg->dev, "Could not allocate descriptors for slot %d", jpeg->slot_data.slot);
>> +	mxc_jpeg_free_slot_data(jpeg);
>>
>>   	return false;
>>   }
>>
>> -static void mxc_jpeg_free_slot_data(struct mxc_jpeg_dev *jpeg)
>> -{
>> -	/* free descriptor for decoding/encoding phase */
>> -	dma_free_coherent(jpeg->dev, sizeof(struct mxc_jpeg_desc),
>> -			  jpeg->slot_data.desc,
>> -			  jpeg->slot_data.desc_handle);
>> -
>> -	/* free descriptor for encoder configuration phase / decoder DHT */
>> -	dma_free_coherent(jpeg->dev, sizeof(struct mxc_jpeg_desc),
>> -			  jpeg->slot_data.cfg_desc,
>> -			  jpeg->slot_data.cfg_desc_handle);
>> -
>> -	/* free configuration stream */
>> -	dma_free_coherent(jpeg->dev, MXC_JPEG_MAX_CFG_STREAM,
>> -			  jpeg->slot_data.cfg_stream_vaddr,
>> -			  jpeg->slot_data.cfg_stream_handle);
>> -
>> -	jpeg->slot_data.used = false;
>> -}
>> -
>>   static void mxc_jpeg_check_and_set_last_buffer(struct mxc_jpeg_ctx *ctx,
>>   					       struct vb2_v4l2_buffer *src_buf,
>>   					       struct vb2_v4l2_buffer *dst_buf)
>> --
>> 2.43.0-rc1
>>