On Sat, Oct 17, 2026 at 05:54:40PM +0200, Greg Kroah-Hartman wrote:
6.6-stable review patch. If anyone has any objections, please let me know.
------------------
From: Eric Dumazet <[email protected]>
[ Upstream commit 059b7dbd20a6f0c539a45ddff1573cb8946685b5 ]
Be careful with this patch, this caused data loss. It's fixed upstream
by commits:
a4f0b001782b ("vsock/virtio: reset connection on receiving queue
overflow")
2a12c05aef21 ("vsock/virtio: collapse receive queue under memory
pressure")
c6087c5aaad6 ("vsock/virtio: fix skb overhead accounting to preserve
full buf_alloc")
So if you want to backport this patch, I strongly recommend that you
include these others as well in the same backport.
Thanks,
Stefano
virtio_transport_inc_rx_pkt() checks vvs->rx_bytes + len > vvs->buf_alloc.
virtio_transport_recv_enqueue() skips coalescing for packets
with VIRTIO_VSOCK_SEQ_EOM.
If fed with packets with len == 0 and VIRTIO_VSOCK_SEQ_EOM,
a very large number of packets can be queued
because vvs->rx_bytes stays at 0.
Fix this by estimating the skb metadata size:
(Number of skbs in the queue) * SKB_TRUESIZE(0)
Fixes: 077706165717 ("virtio/vsock: don't use skbuff state to account credit")
Signed-off-by: Eric Dumazet <[email protected]>
Cc: Arseniy Krasnov <[email protected]>
Cc: Stefan Hajnoczi <[email protected]>
Cc: Stefano Garzarella <[email protected]>
Cc: "Michael S. Tsirkin" <[email protected]>
Cc: Jason Wang <[email protected]>
Cc: Xuan Zhuo <[email protected]>
Cc: "Eugenio Pérez" <[email protected]>
Cc: [email protected]
Link: https://patch.msgid.link/[email protected]
Signed-off-by: Jakub Kicinski <[email protected]>
Signed-off-by: Sasha Levin <[email protected]>
---
net/vmw_vsock/virtio_transport_common.c | 4 +++-
1 file changed, 3 insertions(+), 1 deletion(-)
diff --git a/net/vmw_vsock/virtio_transport_common.c
b/net/vmw_vsock/virtio_transport_common.c
index e2a5803c0bbb7..24aa9194e6862 100644
--- a/net/vmw_vsock/virtio_transport_common.c
+++ b/net/vmw_vsock/virtio_transport_common.c
@@ -283,7 +283,9 @@ static int virtio_transport_send_pkt_info(struct vsock_sock
*vsk,
static bool virtio_transport_inc_rx_pkt(struct virtio_vsock_sock *vvs,
u32 len)
{
- if (vvs->buf_used + len > vvs->buf_alloc)
+ u64 skb_overhead = (skb_queue_len(&vvs->rx_queue) + 1) *
SKB_TRUESIZE(0);
+
+ if (skb_overhead + vvs->buf_used + len > vvs->buf_alloc)
return false;
vvs->rx_bytes += len;
--
2.53.0
