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From: Kevin Easton <kevin@guarana.org>
To: "Michael S. Tsirkin" <mst@redhat.com>
Cc: Jason Wang <jasowang@redhat.com>,
	kvm@vger.kernel.org, virtualization@lists.linux-foundation.org,
	netdev@vger.kernel.org, linux-kernel@vger.kernel.org,
	syzkaller-bugs@googlegroups.com
Subject: Re: [PATCH net] vhost: Use kzalloc() to allocate vhost_msg_node
Date: Tue, 8 May 2018 04:27:16 -0400	[thread overview]
Message-ID: <20180508082716.GA21344@la.guarana.org> (raw)
In-Reply-To: <20180507155534-mutt-send-email-mst@kernel.org>

On Mon, May 07, 2018 at 04:03:25PM +0300, Michael S. Tsirkin wrote:
> On Fri, Apr 27, 2018 at 11:45:02AM -0400, Kevin Easton wrote:
> > The struct vhost_msg within struct vhost_msg_node is copied to userspace,
> > so it should be allocated with kzalloc() to ensure all structure padding
> > is zeroed.
> > 
> > Signed-off-by: Kevin Easton <kevin@guarana.org>
> > Reported-by: syzbot+87cfa083e727a224754b@syzkaller.appspotmail.com
> > ---
> >  drivers/vhost/vhost.c | 2 +-
> >  1 file changed, 1 insertion(+), 1 deletion(-)
> > 
> > diff --git a/drivers/vhost/vhost.c b/drivers/vhost/vhost.c
> > index f3bd8e9..1b84dcff 100644
> > --- a/drivers/vhost/vhost.c
> > +++ b/drivers/vhost/vhost.c
> > @@ -2339,7 +2339,7 @@ EXPORT_SYMBOL_GPL(vhost_disable_notify);
> >  /* Create a new message. */
> >  struct vhost_msg_node *vhost_new_msg(struct vhost_virtqueue *vq, int type)
> >  {
> > -	struct vhost_msg_node *node = kmalloc(sizeof *node, GFP_KERNEL);
> > +	struct vhost_msg_node *node = kzalloc(sizeof *node, GFP_KERNEL);
> >  	if (!node)
> >  		return NULL;
> >  	node->vq = vq;
> 
> 
> Let's just init the msg though.
> 
> OK it seems this is the best we can do for now,
> we need a new feature bit to fix it for 32 bit
> userspace on 64 bit kernels.
> 
> Does the following help?

Yes, the reproducer doesn't trigger the error with that patch applied.

    - Kevin

  parent reply	other threads:[~2018-05-08  8:27 UTC|newest]

Thread overview: 30+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2018-04-23 16:56 KMSAN: uninit-value in _copy_to_iter (2) syzbot
2018-04-25 19:19 ` syzbot
2018-06-07 15:38   ` Michael S. Tsirkin
2018-06-07 15:38     ` syzbot
2018-06-07 16:25     ` Dmitry Vyukov
2018-06-07 17:04       ` syzbot
2018-06-07 17:43     ` Al Viro
2018-06-07 17:59       ` Michael S. Tsirkin
2018-06-07 18:04         ` Al Viro
2018-06-07 19:29           ` Michael S. Tsirkin
2018-06-07 17:10   ` Michael S. Tsirkin
2018-06-07 17:31     ` syzbot
2018-04-27 15:45 ` [PATCH net] vhost: Use kzalloc() to allocate vhost_msg_node Kevin Easton
2018-04-27 16:05   ` Michael S. Tsirkin
2018-04-27 16:11     ` Dmitry Vyukov
2018-04-27 16:15       ` Michael S. Tsirkin
2018-04-27 16:25         ` Dmitry Vyukov
2018-04-27 16:29           ` Dmitry Vyukov
2018-04-27 19:36       ` Michael S. Tsirkin
2018-04-29  8:10         ` Dmitry Vyukov
2018-04-28  1:07     ` Kevin Easton
2018-04-28  1:51       ` Kevin Easton
2018-04-28  2:23         ` Jason Wang
2018-05-07 13:03   ` Michael S. Tsirkin
2018-05-07 13:12     ` Dmitry Vyukov
2018-05-08  8:27     ` Kevin Easton [this message]
2018-05-29 22:19   ` [net] " Guenter Roeck
2018-05-30  3:01     ` Michael S. Tsirkin
2018-05-30  3:42       ` Guenter Roeck
2018-06-04 12:34       ` Dmitry Vyukov

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