linux-kernel - Re: [PATCH v3 1/2] nvmem: Allow nvmem_sysfs_get_groups() to return NULL as error condition

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Date:   Tue, 10 Mar 2020 13:10:39 +0000
From:   Srinivas Kandagatla <srinivas.kandagatla@...aro.org>
To:     Nicholas Johnson <nicholas.johnson-opensource@...look.com.au>,
        "linux-kernel@...r.kernel.org" <linux-kernel@...r.kernel.org>
Cc:     Mika Westerberg <mika.westerberg@...ux.intel.com>
Subject: Re: [PATCH v3 1/2] nvmem: Allow nvmem_sysfs_get_groups() to return
 NULL as error condition



On 09/03/2020 17:49, Nicholas Johnson wrote:
> Currently, nvmem_register() does not check for NULL return from
> nvmem_sysfs_get_groups(), and hence nvmem_sysfs_get_groups() has to
> always return a valid group, even if it is given invalid inputs.
> 
> Add check in nvmem_register() to return an error if NULL group is given.
> 
> Signed-off-by: Nicholas Johnson <nicholas.johnson-opensource@...look.com.au>
> ---
>   drivers/nvmem/core.c | 4 ++++
>   1 file changed, 4 insertions(+)
> 
> diff --git a/drivers/nvmem/core.c b/drivers/nvmem/core.c
> index ef326f243..f6cd8a56a 100644
> --- a/drivers/nvmem/core.c
> +++ b/drivers/nvmem/core.c
> @@ -388,6 +388,10 @@ struct nvmem_device *nvmem_register(const struct nvmem_config *config)
>   			   config->read_only || !nvmem->reg_write;
>   
>   	nvmem->dev.groups = nvmem_sysfs_get_groups(nvmem, config);
Code as it today will never return null so this patch belongs to the 
next patch where its possible to return null.

> +	if (!nvmem->dev.groups) {
> +		kfree(nvmem);

This is still leaking few more things here!
> +		return ERR_PTR(-EPERM);

Error code hear does not really reflect why it failed, we should return 
-EINVAL indicating that its invalid configuration.

--srini
> +	}
>   
>   	device_initialize(&nvmem->dev);
>   
>