Re: [PATCH] vme: remove unneeded kfree

[Greg Kroah-Hartman]

On Thu, Sep 06, 2018 at 10:04:49PM -0700, Linus Torvalds wrote:
> On Thu, Sep 6, 2018 at 1:51 AM Ding Xiang
> <dingxiang@xxxxxxxxxxxxxxxxxxxx> wrote:
> >
> > put_device will call vme_dev_release to free vdev, kfree is
> > unnecessary here.
> 
> That does seem to be the case.  I think "unnecessary" is overly kind,
> it does seem to be a double free.
> 
> Looks like the issue was introduced back in 2013 by commit
> def1820d25fa ("vme: add missing put_device() after device_register()
> fails").
> 
> It seems you should *either* kfree() the vdev, _or_ do put_device(),
> but doing both seems wrong.

You should only ever call put_device() after you have created the
structure, the documentation should say that somewhere...

> I presume the device_register() has never failed, and this being
> vme-only I'm guessing there isn't a vibrant testing community.
> 
> Greg?

It's the correct fix, I'll queue it up soon, thanks.

greg k-h