[PATCH] vhost: Fix vhost_vq_reset()

[PATCH] vhost: Fix vhost_vq_reset()

[Laurent Vivier]

vhost_reset_is_le() is vhost_init_is_le(), and in the case of
cross-endian legacy, vhost_init_is_le() depends on vq->user_be.

vq->user_be is set by vhost_disable_cross_endian().

But in vhost_vq_reset(), we have:

    vhost_reset_is_le(vq);
    vhost_disable_cross_endian(vq);

And so user_be is used before being set.

To fix that, reverse the lines order as there is no other dependency
between them.

Signed-off-by: Laurent Vivier <lvivier@redhat.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 a262e12c6dc2..5ccb0705beae 100644
--- a/drivers/vhost/vhost.c
+++ b/drivers/vhost/vhost.c
@@ -332,8 +332,8 @@ static void vhost_vq_reset(struct vhost_dev *dev,
 	vq->error_ctx = NULL;
 	vq->kick = NULL;
 	vq->log_ctx = NULL;
-	vhost_reset_is_le(vq);
 	vhost_disable_cross_endian(vq);
+	vhost_reset_is_le(vq);
 	vq->busyloop_timeout = 0;
 	vq->umem = NULL;
 	vq->iotlb = NULL;
-- 
2.29.2

Re: [PATCH] vhost: Fix vhost_vq_reset()

[Jason Wang]

在 2021/3/12 下午10:09, Laurent Vivier 写道:
> vhost_reset_is_le() is vhost_init_is_le(), and in the case of
> cross-endian legacy, vhost_init_is_le() depends on vq->user_be.
>
> vq->user_be is set by vhost_disable_cross_endian().
>
> But in vhost_vq_reset(), we have:
>
>      vhost_reset_is_le(vq);
>      vhost_disable_cross_endian(vq);
>
> And so user_be is used before being set.
>
> To fix that, reverse the lines order as there is no other dependency
> between them.
>
> Signed-off-by: Laurent Vivier <lvivier@redhat.com>


Acked-by: Jason Wang <jasowang@redhat.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 a262e12c6dc2..5ccb0705beae 100644
> --- a/drivers/vhost/vhost.c
> +++ b/drivers/vhost/vhost.c
> @@ -332,8 +332,8 @@ static void vhost_vq_reset(struct vhost_dev *dev,
>   	vq->error_ctx = NULL;
>   	vq->kick = NULL;
>   	vq->log_ctx = NULL;
> -	vhost_reset_is_le(vq);
>   	vhost_disable_cross_endian(vq);
> +	vhost_reset_is_le(vq);
>   	vq->busyloop_timeout = 0;
>   	vq->umem = NULL;
>   	vq->iotlb = NULL;

Re: [PATCH] vhost: Fix vhost_vq_reset()

[Stefano Garzarella]

On Fri, Mar 12, 2021 at 03:09:13PM +0100, Laurent Vivier wrote:
>vhost_reset_is_le() is vhost_init_is_le(), and in the case of
>cross-endian legacy, vhost_init_is_le() depends on vq->user_be.
>
>vq->user_be is set by vhost_disable_cross_endian().
>
>But in vhost_vq_reset(), we have:
>
>    vhost_reset_is_le(vq);
>    vhost_disable_cross_endian(vq);
>
>And so user_be is used before being set.
>
>To fix that, reverse the lines order as there is no other dependency
>between them.
>
>Signed-off-by: Laurent Vivier <lvivier@redhat.com>
>---
> drivers/vhost/vhost.c | 2 +-
> 1 file changed, 1 insertion(+), 1 deletion(-)

Reviewed-by: Stefano Garzarella <sgarzare@redhat.com>