Re: [PATCH 1/2] fixes for adt7410

[Lars-Peter Clausen <lars@metafoo.de>]

On 07/15/2012 11:50 PM, Hartmut Knaack wrote:
> 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@gmx.de>
>>> ---
>>> 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?

The correct fix is to call INIT_LIST_HEAD right after the struct which
contains the list has been allocated. Sascha already sent a patch which does
this as well. See: http://www.spinics.net/lists/linux-iio/msg05946.html

- Lars