Received-SPF: pass (google.com: best guess record for domain of linux-kernel-owner@vger.kernel.org designates 209.132.180.67 as permitted sender) client-ip=209.132.180.67;
Date:   Fri, 7 Sep 2018 09:20:56 +0200
From:   Greg Kroah-Hartman <gregkh@linuxfoundation.org>
To:     Linus Torvalds <torvalds@linux-foundation.org>
Cc:     dingxiang@cmss.chinamobile.com,
        Staging subsystem List <devel@driverdev.osuosl.org>,
        martyn@welchs.me.uk, manohar.vanga@gmail.com,
        Linux Kernel Mailing List <linux-kernel@vger.kernel.org>
Subject: Re: [PATCH] vme: remove unneeded kfree
Message-ID: <20180907072056.GB1334@kroah.com>
References: <1536223870-6324-1-git-send-email-dingxiang@cmss.chinamobile.com>
 <CA+55aFxuha1tQXcn+WtbOKzwwmtA8AORb04tMM=hk6jT3ntt3w@mail.gmail.com>
MIME-Version: 1.0
Content-Type: text/plain; charset=us-ascii
Content-Disposition: inline
In-Reply-To: <CA+55aFxuha1tQXcn+WtbOKzwwmtA8AORb04tMM=hk6jT3ntt3w@mail.gmail.com>
User-Agent: Mutt/1.10.1 (2018-07-13)
Sender: linux-kernel-owner@vger.kernel.org
Precedence: bulk

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@cmss.chinamobile.com> 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