netdev - Re: [PATCH net v4 1/2] vhost_net: fix ubuf refcount incorrectly when sendmsg fails

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite for Android: free password hash cracker in your pocket

[<prev] [next>] [<thread-prev] [day] [month] [year] [list]

Message-ID: <ab017214-9090-bff0-93db-a00f022c07e9@redhat.com>
Date:   Fri, 25 Dec 2020 14:38:23 +0800
From:   Jason Wang <jasowang@...hat.com>
To:     wangyunjian <wangyunjian@...wei.com>, netdev@...r.kernel.org,
        mst@...hat.com, willemdebruijn.kernel@...il.com
Cc:     virtualization@...ts.linux-foundation.org,
        jerry.lilijun@...wei.com, chenchanghu@...wei.com,
        xudingke@...wei.com, brian.huangbin@...wei.com
Subject: Re: [PATCH net v4 1/2] vhost_net: fix ubuf refcount incorrectly when
 sendmsg fails


On 2020/12/24 上午10:25, wangyunjian wrote:
> From: Yunjian Wang <wangyunjian@...wei.com>
>
> Currently the vhost_zerocopy_callback() maybe be called to decrease
> the refcount when sendmsg fails in tun. The error handling in vhost
> handle_tx_zerocopy() will try to decrease the same refcount again.
> This is wrong. To fix this issue, we only call vhost_net_ubuf_put()
> when vq->heads[nvq->desc].len == VHOST_DMA_IN_PROGRESS.
>
> Fixes: 0690899b4d45 ("tun: experimental zero copy tx support")
> Signed-off-by: Yunjian Wang <wangyunjian@...wei.com>
> Acked-by: Willem de Bruijn <willemb@...gle.com>
> Acked-by: Michael S. Tsirkin <mst@...hat.com>


Acked-by: Jason Wang <jasowang@...hat.com>


> ---
>   drivers/vhost/net.c | 6 +++---
>   1 file changed, 3 insertions(+), 3 deletions(-)
>
> diff --git a/drivers/vhost/net.c b/drivers/vhost/net.c
> index 531a00d703cd..c8784dfafdd7 100644
> --- a/drivers/vhost/net.c
> +++ b/drivers/vhost/net.c
> @@ -863,6 +863,7 @@ static void handle_tx_zerocopy(struct vhost_net *net, struct socket *sock)
>   	size_t len, total_len = 0;
>   	int err;
>   	struct vhost_net_ubuf_ref *ubufs;
> +	struct ubuf_info *ubuf;
>   	bool zcopy_used;
>   	int sent_pkts = 0;
>   
> @@ -895,9 +896,7 @@ static void handle_tx_zerocopy(struct vhost_net *net, struct socket *sock)
>   
>   		/* use msg_control to pass vhost zerocopy ubuf info to skb */
>   		if (zcopy_used) {
> -			struct ubuf_info *ubuf;
>   			ubuf = nvq->ubuf_info + nvq->upend_idx;
> -
>   			vq->heads[nvq->upend_idx].id = cpu_to_vhost32(vq, head);
>   			vq->heads[nvq->upend_idx].len = VHOST_DMA_IN_PROGRESS;
>   			ubuf->callback = vhost_zerocopy_callback;
> @@ -927,7 +926,8 @@ static void handle_tx_zerocopy(struct vhost_net *net, struct socket *sock)
>   		err = sock->ops->sendmsg(sock, &msg, len);
>   		if (unlikely(err < 0)) {
>   			if (zcopy_used) {
> -				vhost_net_ubuf_put(ubufs);
> +				if (vq->heads[ubuf->desc].len == VHOST_DMA_IN_PROGRESS)
> +					vhost_net_ubuf_put(ubufs);
>   				nvq->upend_idx = ((unsigned)nvq->upend_idx - 1)
>   					% UIO_MAXIOV;
>   			}