[alsa-devel] [PATCH] fix the kernel panic due to wrong use the dev memory API

[Pierre-Louis Bossart]

On 11/5/18 2:29 AM, He, Bo wrote:
> skl->dais is allocated with devm_kcalloc, can't free with
> the krealloc. Memory allocated with devm API is automatically freed
> on driver detach, Like all other devres resources.
>
> Refer to drivers/base/devres.c devm_kmalloc for more details.

What code are you looking at?

I see this in the Mark's tree

int skl_platform_register(struct device *dev)
{
     int ret;
     struct snd_soc_dai_driver *dais;
     int num_dais = ARRAY_SIZE(skl_platform_dai);
     struct hdac_bus *bus = dev_get_drvdata(dev);
     struct skl *skl = bus_to_skl(bus);

     INIT_LIST_HEAD(&skl->ppl_list);
     INIT_LIST_HEAD(&skl->bind_list);

     skl->dais = kmemdup(skl_platform_dai, sizeof(skl_platform_dai),
                 GFP_KERNEL);
     if (!skl->dais) {
         ret = -ENOMEM;
         goto err;
     }

     if (!skl->use_tplg_pcm) {
         dais = krealloc(skl->dais, sizeof(skl_fe_dai) +
                 sizeof(skl_platform_dai), GFP_KERNEL);


No trace of devm as you mention it? I checked the Chrome tree as well 
and it's not there.

What am I missing?


>
> Signed-off-by: he, bo <bo.he at intel.com>
> ---
>   sound/soc/intel/skylake/skl-pcm.c | 5 ++---
>   1 file changed, 2 insertions(+), 3 deletions(-)
>
> diff --git a/sound/soc/intel/skylake/skl-pcm.c b/sound/soc/intel/skylake/skl-pcm.c
> index 823e391..928d314 100644
> --- a/sound/soc/intel/skylake/skl-pcm.c
> +++ b/sound/soc/intel/skylake/skl-pcm.c
> @@ -1438,7 +1438,8 @@ int skl_platform_register(struct device *dev)
>   	}
>   
>   	if (!skl->use_tplg_pcm) {
> -		dais = krealloc(skl->dais, sizeof(skl_fe_dai) +
> +		devm_kfree(dev, skl->dais);
> +		dais = devm_kcalloc(dev, skl->dais, sizeof(skl_fe_dai) +
>   				sizeof(skl_platform_dai), GFP_KERNEL);
>   		if (!dais) {
>   			ret = -ENOMEM;
> @@ -1472,7 +1473,5 @@ int skl_platform_unregister(struct device *dev)
>   		}
>   	}
>   
> -	kfree(skl->dais);
> -
>   	return 0;
>   }