On 06/24/2013 01:30 PM, Otavio Salvador wrote:
> On Sat, Jun 22, 2013 at 8:03 AM, Jonathan Cameron <jic23@xxxxxxxxxx> wrote:
>>> From what I could grasp, it might be related to the IIO subsystem but
>>> I couldn't find the culprit.
>>>
>>> It seems "iio_device_unregister_trigger_consumer", as:
>>>
>>> void iio_device_unregister_trigger_consumer(struct iio_dev *indio_dev)
>>> {
>>> /* Clean up an associated but not attached trigger reference */
>>> if (indio_dev->trig)
>>> iio_trigger_put(indio_dev->trig);
>>> }
>>>
>>> and , as:
>>>
>>> static inline void iio_trigger_put(struct iio_trigger *trig)
>>> {
>>> module_put(trig->ops->owner);
>>> put_device(&trig->dev);
>>> }
>>>
>>> so, somehow the trig->ops is NULL here.
>>>
>>> Do someone has a clue?
>>>
>> I think the issue is more core to iio trigger handling than that, you
>> have just been unlucky enough to hit a bug that has been there a while.
>>
>> In iio_trigger_unregister we call
>> iio_device_unregister which in turn calls device_del (as intended) and
>> device_put (as not!). Then we get an additional device_put from
>> iio_trigger_free giving us one more than we should have an resulting
>> in a double attempt to free the device.
>>
>> Could you try the following change and see if it solves the problem?
>> (the comment abov is 'interesting' and stupid given I've long ago
>> forgotten what it refers to, but it could be related to this issue...)
>>
>> From 238faf76acaa9214b0eb607742dd14b134469328 Mon Sep 17 00:00:00 2001
>> From: Jonathan Cameron <jic23@xxxxxxxxxx>
>> Date: Sat, 22 Jun 2013 12:00:04 +0100
>> Subject: [PATCH] iio:trigger: device_unregister->device_del to avoid double
>> free
>>
>> iio_trigger unregistration and freeing has been separated in this
>> code for some time, but it looks like the calls to the device
>> handling were not appropriately updated.
>>
>> Signed-off-by: Jonathan Cameron <jic23@xxxxxxxxxx>
>> ---
>> drivers/iio/industrialio-trigger.c | 2 +-
>> 1 file changed, 1 insertion(+), 1 deletion(-)
>>
>> diff --git a/drivers/iio/industrialio-trigger.c b/drivers/iio/industrialio-trigger.c
>> index 4d6c7d8..ea8a414 100644
>> --- a/drivers/iio/industrialio-trigger.c
>> +++ b/drivers/iio/industrialio-trigger.c
>> @@ -104,7 +104,7 @@ void iio_trigger_unregister(struct iio_trigger *trig_info)
>>
>> ida_simple_remove(&iio_trigger_ida, trig_info->id);
>> /* Possible issue in here */
>> - device_unregister(&trig_info->dev);
>> + device_del(&trig_info->dev);
>> }
>> EXPORT_SYMBOL(iio_trigger_unregister);
>
> Tested-by: Otavio Salvador <otavio@xxxxxxxxxxxxxxxx>
>
> It does fix the Oops for me.
applied to the fixes-togreg branch of iio.git
Given timing these will probably go in after the merge window closes in a couple of
weeks.
Thanks,
>
> --
> Otavio Salvador O.S. Systems
> http://www.ossystems.com.br http://projetos.ossystems.com.br
> Mobile: +55 (53) 9981-7854 Mobile: +1 (347) 903-9750
> --
> To unsubscribe from this list: send the line "unsubscribe linux-iio" in
> the body of a message to majordomo@xxxxxxxxxxxxxxx
> More majordomo info at http://vger.kernel.org/majordomo-info.html
>
--
To unsubscribe from this list: send the line "unsubscribe linux-iio" in
the body of a message to majordomo@xxxxxxxxxxxxxxx
More majordomo info at http://vger.kernel.org/majordomo-info.html
