[alsa-devel] Question on compress offload framework memory corruption

[Clemens Ladisch]

Re-sending with Liam's correct address (which is _not_ clemens at ladisch.de).

gsantosh at codeaurora.org wrote:
> Hi,
>
> I have following questions in the compressed offload framework API.
>
> static int soc_compr_set_params_fe(struct snd_compr_stream *cstream,
> 					struct snd_compr_params *params)
> {
> ...
> 	hw_params = kzalloc(sizeof(*hw_params), GFP_KERNEL);
> 	if (hw_params == NULL)
> 		return -ENOMEM;
> /*1st question is, what is the use of above allocated memory I do not see
> this being used in this function*/
>
> ...
>
> 	memcpy(&fe->dpcm[fe_substream->stream].hw_params, params,
> 			sizeof(struct snd_pcm_hw_params));
>
> /* 2nd question is
> in above memcpy there is parameter mismatch
> &fe->dpcm[fe_substream->stream].hw_params is of structure type struct
> snd_pcm_hw_params
>
> params argument is of the structure type struct snd_compr_params
> the definition of the two structures are different, how this is working?
> this will over right the destination with junk value which will return
> in error when this memory is accessed, after memcpy this cpu_dai hw_params
> returing with EINVAL error, please explain why this is done this way.
> */
>
> ...
>
> }
>
> Regards,
> Santosh M G.