[alsa-devel] Question on compress offload framework memory corruption
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.
Re sending this as i did not got the response.
--Santosh
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.
Re-sending with Liam's correct address (which is _not_ clemens@ladisch.de).
gsantosh@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.
On Wed, Dec 18, 2013 at 01:17:51PM -0000, gsantosh@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*/
The code you're quoting there isn't in mainline. I've also added Vinod to the CCs, you probably want to include him in any discussion of the compressed API.
On Thu, Dec 19, 2013 at 10:55:08AM +0000, Mark Brown wrote:
On Wed, Dec 18, 2013 at 01:17:51PM -0000, gsantosh@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*/
The code you're quoting there isn't in mainline. I've also added Vinod to the CCs, you probably want to include him in any discussion of the compressed API.
That's right, this is from DPCM compressed updated done by Liam, so he is the best person to comment on this bit, and somehow his address in CC has gone bad, i have added him in to list
But yes looking at the source, i agree that two are interlinked. I guess we need to poupulate the hw_params and then use that to copy, that would be the right thing to do here and yes this is not correct and not sure how this is working...
participants (4)
-
Clemens Ladisch -
gsantosh＠codeaurora.org -
Mark Brown -
Vinod Koul