On 2018/8/16 17:32, Claudiu Beznea wrote:
> Hi Alexandre,
>
> On 14.08.2018 15:59, Alexandre Belloni wrote:
>> On 14/08/2018 09:54:56+0800, zhong jiang wrote:
>>> Device node iterators put the previous value of the index variable,
>>> so an explicit put causes a double put.
>>>
>> While for_each_matching_node_and_match will get and put the node
>> properly, there is also a call to of_find_device_by_node that will get a
>> reference to the node.
>>
> Looking through of_find_device_by_node() it seems that a put_device() on the
> struct device member of the returned struct platform_device has to be called
> instead of of_node_put().
>
> of_find_device_by_node() calls bus_find_device():
>
> dev = bus_find_device(&platform_bus_type, NULL, np, of_dev_node_match);
>
> the match function, of_dev_node_match(), is just as follows:
>
> static int of_dev_node_match(struct device *dev, void *data)
>
> {
>
> return dev->of_node == data;
>
> }
>
>
> but bus_find_device() takes a reference to the struct device returned in case
> it
> founds a match, via get_device():
>
> struct device *bus_find_device(struct bus_type *bus,
>
> struct device *start, void *data,
>
> int (*match)(struct device *dev,
> void*data))
> {
>
> struct klist_iter i;
>
> struct device *dev;
>
>
>
> if (!bus || !bus->p)
>
> return NULL;
>
>
>
> klist_iter_init_node(&bus->p->klist_devices, &i,
>
> (start ? &start->p->knode_bus : NULL));
>
> while ((dev = next_device(&i)))
>
> if (match(dev, data) && get_device(dev))
>
> break;
>
> klist_iter_exit(&i);
>
> return dev;
>
> }
>
>
> So, I think a put_device(&pdev->dev) has to be called in at91_pm_config_ws()
> instead of of_node_put(np). My bad!
Yes, you're right. Thanks, Claudiu. I will repost in v2.
Sincerely,
zhong jiang
> Thank you,
> Claudiu Beznea
>
>>> I detect the issue with the help of Coccinelle.
>>>
>>> Signed-off-by: zhong jiang <zhongji...@huawei.com>
>>> ---
>>> arch/arm/mach-at91/pm.c | 5 +----
>>> 1 file changed, 1 insertion(+), 4 deletions(-)
>>>
>>> diff --git a/arch/arm/mach-at91/pm.c b/arch/arm/mach-at91/pm.c
>>> index 32fae4d..a5ec35f 100644
>>> --- a/arch/arm/mach-at91/pm.c
>>> +++ b/arch/arm/mach-at91/pm.c
>>> @@ -143,15 +143,12 @@ static int at91_pm_config_ws(unsigned int pm_mode,
>>> bool set)
>>>
>>> /* Check if enabled on SHDWC. */
>>> if (wsi->shdwc_mr_bit && !(val & wsi->shdwc_mr_bit))
>>> - goto put_node;
>>> + continue;
>>>
>>> mode |= wsi->pmc_fsmr_bit;
>>> if (wsi->set_polarity)
>>> polarity |= wsi->pmc_fsmr_bit;
>>> }
>>> -
>>> -put_node:
>>> - of_node_put(np);
>>> }
>>>
>>> if (mode) {
>>> --
>>> 1.7.12.4
>>>
> .
>
