Re: [PATCH 2/2 v2] mtd: ubi: use put_device() if device_register fail

[Arvind Yadav]

On Thursday 15 March 2018 01:25 PM, Richard Weinberger wrote:
> Am Donnerstag, 15. März 2018, 08:20:31 CET schrieb Arvind Yadav:
> > if device_register() returned an error! Always use put_device()
> > to give up the reference initialized.
> Like DaveM said, there is no need to shout and use "!".

I will fix this and send you update patch.
>   
> > Signed-off-by: Arvind Yadav <arvind.yadav.cs@xxxxxxxxx>
> > ---
> > change in v2:
> >          Fix use-after-free bug. move put_device() after cdev_del().
> >
> >   drivers/mtd/ubi/vmt.c | 1 +
> >   1 file changed, 1 insertion(+)
> >
> > diff --git a/drivers/mtd/ubi/vmt.c b/drivers/mtd/ubi/vmt.c
> > index 3fd8d7f..93c6163 100644
> > --- a/drivers/mtd/ubi/vmt.c
> > +++ b/drivers/mtd/ubi/vmt.c
> > @@ -610,6 +610,7 @@ int ubi_add_volume(struct ubi_device *ubi, struct
> > ubi_volume *vol)
> >
> >   out_cdev:
> >   	cdev_del(&vol->cdev);
> > +	put_device(&vol->dev);
> >   	return err;
> The more I dig into device code, the more questions I have.
> Why is cdev_del() not part of the release function?
>
> Thanks,
> //richard

Yes, It's should be a part release function.

~arvind