if device_register() returned an error! Always use put_device()
to give up the reference initialized.
Signed-off-by: Arvind Yadav <[email protected]>
---
drivers/ssb/main.c | 1 +
1 file changed, 1 insertion(+)
diff --git a/drivers/ssb/main.c b/drivers/ssb/main.c
index 65420a9..c4449e0 100644
--- a/drivers/ssb/main.c
+++ b/drivers/ssb/main.c
@@ -521,6 +521,7 @@ static int ssb_devices_register(struct ssb_bus *bus)
ssb_err("Could not register %s\n", dev_name(dev));
/* Set dev to NULL to not unregister
* dev on error unwinding. */
+ put_device(dev);
sdev->dev = NULL;
kfree(devwrap);
goto error;
--
1.9.1
On Wed, 7 Mar 2018 15:31:30 +0530
Arvind Yadav <[email protected]> wrote:
> if device_register() returned an error! Always use put_device()
> to give up the reference initialized.
>
> Signed-off-by: Arvind Yadav <[email protected]>
> ---
> drivers/ssb/main.c | 1 +
> 1 file changed, 1 insertion(+)
>
> diff --git a/drivers/ssb/main.c b/drivers/ssb/main.c
> index 65420a9..c4449e0 100644
> --- a/drivers/ssb/main.c
> +++ b/drivers/ssb/main.c
> @@ -521,6 +521,7 @@ static int ssb_devices_register(struct ssb_bus *bus)
> ssb_err("Could not register %s\n", dev_name(dev));
> /* Set dev to NULL to not unregister
> * dev on error unwinding. */
> + put_device(dev);
> sdev->dev = NULL;
> kfree(devwrap);
> goto error;
I don't think this is correct.
The dev structure is allocated as part of devwrap, which is freed here.
Why do you think we need put_device here?
--
Michael
On Wednesday 07 March 2018 10:17 PM, Michael B?sch wrote:
> On Wed, 7 Mar 2018 15:31:30 +0530
> Arvind Yadav <[email protected]> wrote:
>
>> if device_register() returned an error! Always use put_device()
>> to give up the reference initialized.
>>
>> Signed-off-by: Arvind Yadav <[email protected]>
>> ---
>> drivers/ssb/main.c | 1 +
>> 1 file changed, 1 insertion(+)
>>
>> diff --git a/drivers/ssb/main.c b/drivers/ssb/main.c
>> index 65420a9..c4449e0 100644
>> --- a/drivers/ssb/main.c
>> +++ b/drivers/ssb/main.c
>> @@ -521,6 +521,7 @@ static int ssb_devices_register(struct ssb_bus *bus)
>> ssb_err("Could not register %s\n", dev_name(dev));
>> /* Set dev to NULL to not unregister
>> * dev on error unwinding. */
>> + put_device(dev);
>> sdev->dev = NULL;
>> kfree(devwrap);
>> goto error;
>
> I don't think this is correct.
> The dev structure is allocated as part of devwrap, which is freed here.
>
> Why do you think we need put_device here?
>
Yes this patch is not correct, We must not use kfree() after you called
device_register() (even
if it was not successful!) -- see the comment for device_register().
I will delete kfree() and send updated patch.
~arvind
On Wed, 7 Mar 2018 22:46:14 +0530
arvindY <[email protected]> wrote:
> >> diff --git a/drivers/ssb/main.c b/drivers/ssb/main.c
> >> index 65420a9..c4449e0 100644
> >> --- a/drivers/ssb/main.c
> >> +++ b/drivers/ssb/main.c
> >> @@ -521,6 +521,7 @@ static int ssb_devices_register(struct ssb_bus *bus)
> >> ssb_err("Could not register %s\n", dev_name(dev));
> >> /* Set dev to NULL to not unregister
> >> * dev on error unwinding. */
> >> + put_device(dev);
> >> sdev->dev = NULL;
> >> kfree(devwrap);
> >> goto error;
> >
> > I don't think this is correct.
> > The dev structure is allocated as part of devwrap, which is freed here.
> >
> > Why do you think we need put_device here?
> >
> Yes this patch is not correct, We must not use kfree() after you called
> device_register() (even
> if it was not successful!) -- see the comment for device_register().
> I will delete kfree() and send updated patch.
Is device_put() going to call ssb_release_dev() to free the structure?
Can you please elaborate on why device_put() must be used? The comment
is not really of any use here.
--
Michael
On Wednesday 07 March 2018 11:08 PM, Michael B?sch wrote:
> On Wed, 7 Mar 2018 22:46:14 +0530
> arvindY <[email protected]> wrote:
>>>> diff --git a/drivers/ssb/main.c b/drivers/ssb/main.c
>>>> index 65420a9..c4449e0 100644
>>>> --- a/drivers/ssb/main.c
>>>> +++ b/drivers/ssb/main.c
>>>> @@ -521,6 +521,7 @@ static int ssb_devices_register(struct ssb_bus *bus)
>>>> ssb_err("Could not register %s\n", dev_name(dev));
>>>> /* Set dev to NULL to not unregister
>>>> * dev on error unwinding. */
>>>> + put_device(dev);
>>>> sdev->dev = NULL;
>>>> kfree(devwrap);
>>>> goto error;
>>> I don't think this is correct.
>>> The dev structure is allocated as part of devwrap, which is freed here.
>>>
>>> Why do you think we need put_device here?
>>>
>> Yes this patch is not correct, We must not use kfree() after you called
>> device_register() (even
>> if it was not successful!) -- see the comment for device_register().
>> I will delete kfree() and send updated patch.
>
> Is device_put() going to call ssb_release_dev() to free the structure?
>
> Can you please elaborate on why device_put() must be used? The comment
> is not really of any use here.
>
put_device() will call kobject_put(). By calling this, The kobject core
will automatically
clean up all of the memory allocated with the kobject. Internally
kobject_put() will call
kobject_cleanup() which is responsible to call 'dev -> release' and also
free other
kobject resources. we should always avoid kfree() if device_register()
returned an error.
Otherwise it'll not do clean up of other kobject resources.
~arvind