From: Amit Shah on
On (Sat) May 15 2010 [11:45:53], Julia Lawall wrote:
> From: Julia Lawall <julia(a)diku.dk>
>
> In each case, the first argument to send_control_msg or __send_control_msg,
> respectively, has either not been successfully allocated or has been freed
> at the point of the call. In the first case, the first argument, port, is
> only used to access the portdev and id fields, in order to call
> __send_control_msg. Thus it seems possible instead to call
> __send_control_msg directly. In the second case, the call to
> __send_control_msg is moved up to a place where it seems like the first
> argument, portdev, has been initialized sufficiently to make the call to
> __send_control_msg meaningful.
>
> This has only been compile tested.
>
> A simplified version of the semantic match that finds this problem is as
> follows: (http://coccinelle.lip6.fr/)
>
> // <smpl>
> @free@
> expression E;
> position p;
> @@
> kfree@p(E)
>
> @@
> expression free.E, subE<=free.E, E1;
> position free.p;
> @@
>
> kfree@p(E)
> ...
> (
> subE = E1
> |
> * E
> )
> // </smpl>
>
> Signed-off-by: Julia Lawall <julia(a)diku.dk>

Acked-by: Amit Shah <amit.shah(a)redhat.com>

Thanks, Julia.

Rusty, please pick this patch. Thanks.

>
> ---
> drivers/char/virtio_console.c | 8 ++++----
> 1 file changed, 4 insertions(+), 4 deletions(-)
>
> diff --git a/drivers/char/virtio_console.c b/drivers/char/virtio_console.c
> index 458d907..8c99bf1 100644
> --- a/drivers/char/virtio_console.c
> +++ b/drivers/char/virtio_console.c
> @@ -1090,7 +1090,7 @@ free_port:
> kfree(port);
> fail:
> /* The host might want to notify management sw about port add failure */
> - send_control_msg(port, VIRTIO_CONSOLE_PORT_READY, 0);
> + __send_control_msg(portdev, id, VIRTIO_CONSOLE_PORT_READY, 0);
> return err;
> }
>
> @@ -1559,6 +1559,9 @@ static int __devinit virtcons_probe(struct virtio_device *vdev)
> return 0;
>
> free_vqs:
> + /* The host might want to notify mgmt sw about device add failure */
> + __send_control_msg(portdev, VIRTIO_CONSOLE_BAD_ID,
> + VIRTIO_CONSOLE_DEVICE_READY, 0);
> vdev->config->del_vqs(vdev);
> kfree(portdev->in_vqs);
> kfree(portdev->out_vqs);
> @@ -1567,9 +1570,6 @@ free_chrdev:
> free:
> kfree(portdev);
> fail:
> - /* The host might want to notify mgmt sw about device add failure */
> - __send_control_msg(portdev, VIRTIO_CONSOLE_BAD_ID,
> - VIRTIO_CONSOLE_DEVICE_READY, 0);
> return err;
> }
>

Amit
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From: Rusty Russell on
On Mon, 17 May 2010 06:31:40 pm Amit Shah wrote:
> On (Sat) May 15 2010 [11:45:53], Julia Lawall wrote:
> > From: Julia Lawall <julia(a)diku.dk>
....
> > Signed-off-by: Julia Lawall <julia(a)diku.dk>
>
> Acked-by: Amit Shah <amit.shah(a)redhat.com>
>
> Thanks, Julia.
>
> Rusty, please pick this patch. Thanks.

Done.

Thanks!
Rusty.
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