From mboxrd@z Thu Jan  1 00:00:00 1970
From: Joe Perches <joe@perches.com>
Subject: Re: [PATCH V2 1/3] kvm: use kmalloc() instead of kzalloc() during
 iodev register/unregister
Date: Tue, 25 Aug 2015 22:45:47 -0700
Message-ID: <1440567947.2670.179.camel@perches.com>
References: <1440488835-4388-1-git-send-email-jasowang@redhat.com>
	 <1440516546.2670.88.camel@perches.com> <55DD50FA.1050608@redhat.com>
Mime-Version: 1.0
Content-Type: text/plain; charset="ISO-8859-1"
Content-Transfer-Encoding: 7bit
Cc: gleb@kernel.org, pbonzini@redhat.com, kvm@vger.kernel.org,
	linux-kernel@vger.kernel.org, cornelia.huck@de.ibm.com,
	"Michael S. Tsirkin" <mst@redhat.com>
To: Jason Wang <jasowang@redhat.com>
Return-path: <linux-kernel-owner@vger.kernel.org>
In-Reply-To: <55DD50FA.1050608@redhat.com>
Sender: linux-kernel-owner@vger.kernel.org
List-Id: kvm.vger.kernel.org

On Wed, 2015-08-26 at 13:39 +0800, Jason Wang wrote:
> 
> On 08/25/2015 11:29 PM, Joe Perches wrote:
> > On Tue, 2015-08-25 at 15:47 +0800, Jason Wang wrote:
> >> > All fields of kvm_io_range were initialized or copied explicitly
> >> > afterwards. So switch to use kmalloc().
> > Is there any compiler added alignment padding
> > in either structure?  If so, those padding
> > areas would now be uninitialized and may leak
> > kernel data if copied to user-space.
> >
> I get your concern, but I don't a way to copy them to userspace, did you?

I didn't look.

I just wanted you to be aware there's a difference
and a reason why kzalloc might be used even though
all structure members are initialized.