linux-kernel - Re: [PATCH] vhost: Fix vhost_vq

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Message-ID: <7bb4ee1a-d204-eb94-792f-ca250dacacea@redhat.com>
Date:   Mon, 15 Mar 2021 16:31:11 +0800
From:   Jason Wang <jasowang@...hat.com>
To:     Laurent Vivier <lvivier@...hat.com>, linux-kernel@...r.kernel.org
Cc:     virtualization@...ts.linux-foundation.org, netdev@...r.kernel.org,
        "Michael S. Tsirkin" <mst@...hat.com>, kvm@...r.kernel.org
Subject: Re: [PATCH] vhost: Fix vhost_vq_reset()


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@...hat.com>


Acked-by: Jason Wang <jasowang@...hat.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;