diff mbox series

[net,v4,1/2] vhost_net: fix ubuf refcount incorrectly when sendmsg fails

Message ID 1608776738-21868-1-git-send-email-wangyunjian@huawei.com (mailing list archive)
State Superseded
Delegated to: Netdev Maintainers
Headers show
Series fixes for vhost_net | expand

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Commit Message

wangyunjian Dec. 24, 2020, 2:25 a.m. UTC 
From: Yunjian Wang <wangyunjian@huawei.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@huawei.com>
Acked-by: Willem de Bruijn <willemb@google.com>
Acked-by: Michael S. Tsirkin <mst@redhat.com>
---
 drivers/vhost/net.c | 6 +++---
 1 file changed, 3 insertions(+), 3 deletions(-)

Comments

Jason Wang Dec. 25, 2020, 6:38 a.m. UTC | #1 
On 2020/12/24 上午10:25, wangyunjian wrote:
> From: Yunjian Wang <wangyunjian@huawei.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@huawei.com>
> Acked-by: Willem de Bruijn <willemb@google.com>
> Acked-by: Michael S. Tsirkin <mst@redhat.com>


Acked-by: Jason Wang <jasowang@redhat.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;
>   			}
diff mbox series

Patch

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;
 			}