Re: [PATCH 1/2] fixes for adt7410

[Hartmut Knaack <knaack.h@xxxxxx>]

Lars-Peter Clausen schrieb:
> On 07/15/2012 10:40 PM, Hartmut Knaack wrote:
>> This patch adds some checks prior to accessing device attribute lists in industrialio-event.c.
>>
>> Signed-off-by: Harmut Knaack <knaack.h@xxxxxx>
>> ---
>> diff --git a/drivers/iio/industrialio-event.c b/drivers/iio/industrialio-event.c
>> index b49059d..fe68e90 100644
>> --- a/drivers/iio/industrialio-event.c
>> +++ b/drivers/iio/industrialio-event.c
>> @@ -425,11 +425,13 @@ int iio_device_register_eventset(struct iio_dev *indio_dev)
>>                 *attrcount_orig);
>>      attrn = attrcount_orig;
>>      /* Add all elements from the list. */
>> -    list_for_each_entry(p,
>> -                &indio_dev->event_interface->dev_attr_list,
>> -                l)
>> -        indio_dev->event_interface->group.attrs[attrn++] =
>> -            &p->dev_attr.attr;
>> +    if (indio_dev->event_interface->dev_attr_list.next)
> next should never be NULL. If it is this means that INIT_LIST_HEAD has not
> been called on the list and the correct fix is to make sure that it is called.
Exactly. If the channels-attributes have not been set, INIT_LIST_HEAD (called through __iio_add_event_config_attrs) is not called. So, should we just stop instantiating the device if it does not have channel information?
>
>> +        list_for_each_entry(p,
>> +                &indio_dev->event_interface->dev_attr_list,
>> +                l)
>> +            indio_dev->event_interface->group.attrs[attrn++] =
>> +                &p->dev_attr.attr;
>> +
>>      indio_dev->groups[indio_dev->groupcounter++] =
>>          &indio_dev->event_interface->group;
>>  
>> @@ -447,7 +449,9 @@ void iio_device_unregister_eventset(struct iio_dev *indio_dev)
>>  {
>>      if (indio_dev->event_interface == NULL)
>>          return;
>> -    __iio_remove_event_config_attrs(indio_dev);
>> -    kfree(indio_dev->event_interface->group.attrs);
>> +    if (indio_dev->event_interface->dev_attr_list.next)
>> +        __iio_remove_event_config_attrs(indio_dev);
> Same here.
>
>> +    if (indio_dev->event_interface->group.attrs)
>> +        kfree(indio_dev->event_interface->group.attrs);
> kfree does a check for NULL itself.
>
>>      kfree(indio_dev->event_interface);
>>  }
>>
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