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* [PATCH net v5 1/2] vhost_net: fix ubuf refcount incorrectly when sendmsg fails
@ 2020-12-25  7:24 wangyunjian
  2020-12-27 11:23   ` Michael S. Tsirkin
  0 siblings, 1 reply; 6+ messages in thread
From: wangyunjian @ 2020-12-25  7:24 UTC (permalink / raw)
  To: netdev, mst, jasowang, willemdebruijn.kernel
  Cc: virtualization, jerry.lilijun, chenchanghu, xudingke,
	brian.huangbin, Yunjian Wang

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;
 			}
-- 
2.23.0


^ permalink raw reply related	[flat|nested] 6+ messages in thread

* Re: [PATCH net v5 1/2] vhost_net: fix ubuf refcount incorrectly when sendmsg fails
  2020-12-25  7:24 [PATCH net v5 1/2] vhost_net: fix ubuf refcount incorrectly when sendmsg fails wangyunjian
@ 2020-12-27 11:23   ` Michael S. Tsirkin
  0 siblings, 0 replies; 6+ messages in thread
From: Michael S. Tsirkin @ 2020-12-27 11:23 UTC (permalink / raw)
  To: wangyunjian
  Cc: netdev, jasowang, willemdebruijn.kernel, virtualization,
	jerry.lilijun, chenchanghu, xudingke, brian.huangbin

On Fri, Dec 25, 2020 at 03:24:25PM +0800, 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")

Are you sure about this tag? the patch in question only affects
tun, while the fix only affects vhost.

> 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;
>  			}
> -- 
> 2.23.0


^ permalink raw reply	[flat|nested] 6+ messages in thread

* Re: [PATCH net v5 1/2] vhost_net: fix ubuf refcount incorrectly when sendmsg fails
@ 2020-12-27 11:23   ` Michael S. Tsirkin
  0 siblings, 0 replies; 6+ messages in thread
From: Michael S. Tsirkin @ 2020-12-27 11:23 UTC (permalink / raw)
  To: wangyunjian
  Cc: willemdebruijn.kernel, netdev, jerry.lilijun, virtualization,
	xudingke, brian.huangbin, chenchanghu

On Fri, Dec 25, 2020 at 03:24:25PM +0800, 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")

Are you sure about this tag? the patch in question only affects
tun, while the fix only affects vhost.

> 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;
>  			}
> -- 
> 2.23.0

_______________________________________________
Virtualization mailing list
Virtualization@lists.linux-foundation.org
https://lists.linuxfoundation.org/mailman/listinfo/virtualization

^ permalink raw reply	[flat|nested] 6+ messages in thread

* Re: [PATCH net v5 1/2] vhost_net: fix ubuf refcount incorrectly when sendmsg fails
  2020-12-27 11:23   ` Michael S. Tsirkin
@ 2020-12-27 16:14     ` Willem de Bruijn
  -1 siblings, 0 replies; 6+ messages in thread
From: Willem de Bruijn @ 2020-12-27 16:14 UTC (permalink / raw)
  To: Michael S. Tsirkin
  Cc: wangyunjian, Network Development, Jason Wang, Willem de Bruijn,
	virtualization, Lilijun (Jerry),
	chenchanghu, xudingke, huangbin (J)

On Sun, Dec 27, 2020 at 6:26 AM Michael S. Tsirkin <mst@redhat.com> wrote:
>
> On Fri, Dec 25, 2020 at 03:24:25PM +0800, 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")
>
> Are you sure about this tag? the patch in question only affects
> tun, while the fix only affects vhost.

That was my suggestion. But you're right. Perhaps better:

Fixes: bab632d69ee4 ("vhost: vhost TX zero-copy support")

That introduces the actual block that releases the buffer on error:

"
                err = sock->ops->sendmsg(NULL, sock, &msg, len);
                if (unlikely(err < 0)) {
+                       if (zcopy) {
+                               if (ubufs)
+                                       vhost_ubuf_put(ubufs);
+                               vq->upend_idx = ((unsigned)vq->upend_idx - 1) %
+                                       UIO_MAXIOV;
+                       }
"

^ permalink raw reply	[flat|nested] 6+ messages in thread

* Re: [PATCH net v5 1/2] vhost_net: fix ubuf refcount incorrectly when sendmsg fails
@ 2020-12-27 16:14     ` Willem de Bruijn
  0 siblings, 0 replies; 6+ messages in thread
From: Willem de Bruijn @ 2020-12-27 16:14 UTC (permalink / raw)
  To: Michael S. Tsirkin
  Cc: Willem de Bruijn, Network Development, wangyunjian,
	Lilijun (Jerry), virtualization, xudingke, huangbin (J),
	chenchanghu

On Sun, Dec 27, 2020 at 6:26 AM Michael S. Tsirkin <mst@redhat.com> wrote:
>
> On Fri, Dec 25, 2020 at 03:24:25PM +0800, 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")
>
> Are you sure about this tag? the patch in question only affects
> tun, while the fix only affects vhost.

That was my suggestion. But you're right. Perhaps better:

Fixes: bab632d69ee4 ("vhost: vhost TX zero-copy support")

That introduces the actual block that releases the buffer on error:

"
                err = sock->ops->sendmsg(NULL, sock, &msg, len);
                if (unlikely(err < 0)) {
+                       if (zcopy) {
+                               if (ubufs)
+                                       vhost_ubuf_put(ubufs);
+                               vq->upend_idx = ((unsigned)vq->upend_idx - 1) %
+                                       UIO_MAXIOV;
+                       }
"
_______________________________________________
Virtualization mailing list
Virtualization@lists.linux-foundation.org
https://lists.linuxfoundation.org/mailman/listinfo/virtualization

^ permalink raw reply	[flat|nested] 6+ messages in thread

* RE: [PATCH net v5 1/2] vhost_net: fix ubuf refcount incorrectly when sendmsg fails
  2020-12-27 16:14     ` Willem de Bruijn
  (?)
@ 2020-12-28 11:58     ` wangyunjian
  -1 siblings, 0 replies; 6+ messages in thread
From: wangyunjian @ 2020-12-28 11:58 UTC (permalink / raw)
  To: Willem de Bruijn, Michael S. Tsirkin
  Cc: Network Development, Jason Wang, virtualization, Lilijun (Jerry),
	chenchanghu, xudingke, huangbin (J)

> -----Original Message-----
> From: Willem de Bruijn [mailto:willemdebruijn.kernel@gmail.com]
> Sent: Monday, December 28, 2020 12:15 AM
> To: Michael S. Tsirkin <mst@redhat.com>
> Cc: wangyunjian <wangyunjian@huawei.com>; Network Development
> <netdev@vger.kernel.org>; Jason Wang <jasowang@redhat.com>; Willem de
> Bruijn <willemdebruijn.kernel@gmail.com>;
> virtualization@lists.linux-foundation.org; Lilijun (Jerry)
> <jerry.lilijun@huawei.com>; chenchanghu <chenchanghu@huawei.com>;
> xudingke <xudingke@huawei.com>; huangbin (J)
> <brian.huangbin@huawei.com>
> Subject: Re: [PATCH net v5 1/2] vhost_net: fix ubuf refcount incorrectly when
> sendmsg fails
> 
> On Sun, Dec 27, 2020 at 6:26 AM Michael S. Tsirkin <mst@redhat.com> wrote:
> >
> > On Fri, Dec 25, 2020 at 03:24:25PM +0800, 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")
> >
> > Are you sure about this tag? the patch in question only affects tun,
> > while the fix only affects vhost.
> 
> That was my suggestion. But you're right. Perhaps better:
> 
> Fixes: bab632d69ee4 ("vhost: vhost TX zero-copy support")

OK, thanks, I will fix it in next version.

> 
> That introduces the actual block that releases the buffer on error:
> 
> "
>                 err = sock->ops->sendmsg(NULL, sock, &msg, len);
>                 if (unlikely(err < 0)) {
> +                       if (zcopy) {
> +                               if (ubufs)
> +                                       vhost_ubuf_put(ubufs);
> +                               vq->upend_idx =
> ((unsigned)vq->upend_idx - 1) %
> +                                       UIO_MAXIOV;
> +                       }
> "

^ permalink raw reply	[flat|nested] 6+ messages in thread

end of thread, other threads:[~2020-12-28 11:59 UTC | newest]

Thread overview: 6+ messages (download: mbox.gz / follow: Atom feed)
-- links below jump to the message on this page --
2020-12-25  7:24 [PATCH net v5 1/2] vhost_net: fix ubuf refcount incorrectly when sendmsg fails wangyunjian
2020-12-27 11:23 ` Michael S. Tsirkin
2020-12-27 11:23   ` Michael S. Tsirkin
2020-12-27 16:14   ` Willem de Bruijn
2020-12-27 16:14     ` Willem de Bruijn
2020-12-28 11:58     ` wangyunjian

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