[PATCH 1/1] dma: bcm6348: incorrect buffer allocation

[Heinrich Schuchardt]

On 12/27/20 11:18 AM, Álvaro Fernández Rojas wrote:
> Hello Heinrich,
>
> This is not swapped.
> busy_desc is only used in RX. Please, check the rest of the driver:
> https://github.com/u-boot/u-boot/blob/master/drivers/dma/bcm6348-iudma.c
>
> Regards,
> Álvaro.

Thanks for reviewing. Why is calloc called with count = 0? Couldn't we
as well assign NULL?

Best regards

Heinrich

>
> El 27/12/2020 a las 10:26, Heinrich Schuchardt escribió:
>> Calling calloc() for 0 members does not make any sense.
>> Setting ch_priv->busy_desc = NULL for ch_priv->desc_cnt > 0 is equally
>> unreasonable.
>>
>> The current code will lead to a NULL dereference in
>> bcm6348_iudma_enable().
>>
>> The assignments for ch_priv->busy_desc are obviously swapped.
>>
>> Signed-off-by: Heinrich Schuchardt <xypron.glpk at gmx.de>
>> ---
>> I have no device to actually test the driver.
>> ---
>>   drivers/dma/bcm6348-iudma.c | 4 ++--
>>   1 file changed, 2 insertions(+), 2 deletions(-)
>>
>> diff --git a/drivers/dma/bcm6348-iudma.c b/drivers/dma/bcm6348-iudma.c
>> index 91172d483c..81597c56a7 100644
>> --- a/drivers/dma/bcm6348-iudma.c
>> +++ b/drivers/dma/bcm6348-iudma.c
>> @@ -313,10 +313,10 @@ static int bcm6348_iudma_request(struct dma *dma)
>>       ch_priv->desc_id = 0;
>>       if (bcm6348_iudma_chan_is_rx(dma->id)) {
>>           ch_priv->desc_cnt = 0;
>> -        ch_priv->busy_desc = calloc(ch_priv->desc_cnt, sizeof(bool));
>> +        ch_priv->busy_desc = NULL;
>>       } else {
>>           ch_priv->desc_cnt = ch_priv->dma_ring_size;
>> -        ch_priv->busy_desc = NULL;
>> +        ch_priv->busy_desc = calloc(ch_priv->desc_cnt, sizeof(bool));
>>       }
>>
>>       return 0;
>> --
>> 2.29.2
>>