[PATCH net-next v11 04/13] virtio: set skb owner of virtio_transport_reset_no_sock() reply

Bobby Eshleman posted 13 patches 1 week, 3 days ago
There is a newer version of this series
[PATCH net-next v11 04/13] virtio: set skb owner of virtio_transport_reset_no_sock() reply
Posted by Bobby Eshleman 1 week, 3 days ago
From: Bobby Eshleman <bobbyeshleman@meta.com>

Associate reply packets with the sending socket. When vsock must reply
with an RST packet and there exists a sending socket (e.g., for
loopback), setting the skb owner to the socket correctly handles
reference counting between the skb and sk (i.e., the sk stays alive
until the skb is freed).

This allows the net namespace to be used for socket lookups for the
duration of the reply skb's lifetime, preventing race conditions between
the namespace lifecycle and vsock socket search using the namespace
pointer.

Signed-off-by: Bobby Eshleman <bobbyeshleman@meta.com>
---
Changes in v11:
- move before adding to netns support (Stefano)

Changes in v10:
- break this out into its own patch for easy revert (Stefano)
---
 net/vmw_vsock/virtio_transport_common.c | 6 ++++++
 1 file changed, 6 insertions(+)

diff --git a/net/vmw_vsock/virtio_transport_common.c b/net/vmw_vsock/virtio_transport_common.c
index dcc8a1d5851e..675eb9d83549 100644
--- a/net/vmw_vsock/virtio_transport_common.c
+++ b/net/vmw_vsock/virtio_transport_common.c
@@ -1165,6 +1165,12 @@ static int virtio_transport_reset_no_sock(const struct virtio_transport *t,
 		.op = VIRTIO_VSOCK_OP_RST,
 		.type = le16_to_cpu(hdr->type),
 		.reply = true,
+
+		/* Set sk owner to socket we are replying to (may be NULL for
+		 * non-loopback). This keeps a reference to the sock and
+		 * sock_net(sk) until the reply skb is freed.
+		 */
+		.vsk = vsock_sk(skb->sk),
 	};
 	struct sk_buff *reply;
 

-- 
2.47.3
Re: [PATCH net-next v11 04/13] virtio: set skb owner of virtio_transport_reset_no_sock() reply
Posted by Stefano Garzarella 1 week, 3 days ago
On Thu, Nov 20, 2025 at 09:44:36PM -0800, Bobby Eshleman wrote:
>From: Bobby Eshleman <bobbyeshleman@meta.com>
>
>Associate reply packets with the sending socket. When vsock must reply
>with an RST packet and there exists a sending socket (e.g., for
>loopback), setting the skb owner to the socket correctly handles
>reference counting between the skb and sk (i.e., the sk stays alive
>until the skb is freed).
>
>This allows the net namespace to be used for socket lookups for the
>duration of the reply skb's lifetime, preventing race conditions between
>the namespace lifecycle and vsock socket search using the namespace
>pointer.
>
>Signed-off-by: Bobby Eshleman <bobbyeshleman@meta.com>
>---
>Changes in v11:
>- move before adding to netns support (Stefano)
>
>Changes in v10:
>- break this out into its own patch for easy revert (Stefano)
>---
> net/vmw_vsock/virtio_transport_common.c | 6 ++++++
> 1 file changed, 6 insertions(+)

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

>
>diff --git a/net/vmw_vsock/virtio_transport_common.c b/net/vmw_vsock/virtio_transport_common.c
>index dcc8a1d5851e..675eb9d83549 100644
>--- a/net/vmw_vsock/virtio_transport_common.c
>+++ b/net/vmw_vsock/virtio_transport_common.c
>@@ -1165,6 +1165,12 @@ static int virtio_transport_reset_no_sock(const struct virtio_transport *t,
> 		.op = VIRTIO_VSOCK_OP_RST,
> 		.type = le16_to_cpu(hdr->type),
> 		.reply = true,
>+
>+		/* Set sk owner to socket we are replying to (may be NULL for
>+		 * non-loopback). This keeps a reference to the sock and
>+		 * sock_net(sk) until the reply skb is freed.
>+		 */
>+		.vsk = vsock_sk(skb->sk),
> 	};
> 	struct sk_buff *reply;
>
>
>-- 
>2.47.3
>