From mboxrd@z Thu Jan 1 00:00:00 1970 From: Bo Shen Subject: Re: ASoC: atmel-pcm-dma: Leaking memory in atmel_pcm_hw_params Date: Tue, 19 Mar 2013 09:18:43 +0800 Message-ID: <5147BCF3.6060106@atmel.com> References: <5145D5BE.3090501@metafoo.de> <51469121.3070902@atmel.com> <51473462.7030605@metafoo.de> Mime-Version: 1.0 Content-Type: text/plain; charset="us-ascii"; Format="flowed" Content-Transfer-Encoding: 7bit Return-path: Received: from sjogate2.atmel.com (newsmtp5.atmel.com [204.2.163.5]) by alsa0.perex.cz (Postfix) with ESMTP id D90E1265CA9 for ; Tue, 19 Mar 2013 02:19:46 +0100 (CET) In-Reply-To: <51473462.7030605@metafoo.de> List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Errors-To: alsa-devel-bounces@alsa-project.org Sender: alsa-devel-bounces@alsa-project.org To: Lars-Peter Clausen Cc: Linux-ALSA , Nicolas Ferre List-Id: alsa-devel@alsa-project.org Hi Lars, On 3/18/2013 23:36, Lars-Peter Clausen wrote: > On 03/18/2013 04:59 AM, Bo Shen wrote: >> Hi Lars, >> >> On 3/17/2013 22:39, Lars-Peter Clausen wrote: >>> Hi, >>> >>> The dmaengine based pcm driver for atmel calls snd_dmaengine_pcm_open from >>> it's hw_params callback. There is nothing preventing an application calling >>> hw_params more than once. snd_dmaengine_pcm_open allocates a new prtd struct >>> each time it gets called. So in case hw_params is called multiple times we >>> leak memory here. >> >> I use alsa utils and don't meet this issue. Please point out which software >> you use meet this issue. > > I found the issue by looking at the code, but I think any application using > the oss compatibility layer of ALSA will trigger this. Thanks for this information. > >> >>> Is there any specific reason why snd_dmaengine_pcm_open() needs to be called >>> from the hw_params callback and why it can't be called from the open >>> callback? >> >> This is because dma data setting and usage. >> >> The filter function depends on the data returned by >>> snd_soc_dai_get_dma_data(), but as far as I can see the DAI driver calls >>> snd_soc_dai_set_dma_data() from its startup() callback, so the data is >>> available in the PCM drivers open callback. >> >> Have you test this yet? > > I don't have the hardware. I just looked at the code again, and it looks > like I must have misread it the first time. snd_soc_dai_set_dma_data() is > called from the DAI drivers hwparams callback. But the data that gets passed > to snd_soc_dai_set_dma_data() doesn't really depend on anything that's only > available in the hwparams callback. So the snd_soc_dai_set_dma_data() could > easily be move to the DAI driver startup() callback. I will implement this, and send patch for this. Thanks again. > - Lars > Best Regards, Bo Shen