From d2abc563e4ba4057b9cb5c04dd203b8c3a949115 Mon Sep 17 00:00:00 2001 From: Yuri Benditovich Date: Thu, 12 Nov 2020 11:46:53 +0200 Subject: [PATCH] net: purge queued rx packets on queue deletion https://bugzilla.redhat.com/show_bug.cgi?id=1829272 When deleting queue pair, purge pending RX packets if any. Example of problematic flow: 1. Bring up q35 VM with tap (vhost off) and virtio-net or e1000e 2. Run ping flood to the VM NIC ( 1 ms interval) 3. Hot unplug the NIC device (device_del) During unplug process one or more packets come, the NIC can't receive, tap disables read_poll 4. Hot plug the device (device_add) with the same netdev The tap stays with read_poll disabled and does not receive any packets anymore (tap_send never triggered) Signed-off-by: Yuri Benditovich Signed-off-by: Jason Wang --- net/net.c | 12 ++++++++---- 1 file changed, 8 insertions(+), 4 deletions(-) diff --git a/net/net.c b/net/net.c index 6362d3077c..6a2c3d9567 100644 --- a/net/net.c +++ b/net/net.c @@ -412,10 +412,14 @@ void qemu_del_nic(NICState *nic) qemu_macaddr_set_free(&nic->conf->macaddr); - /* If this is a peer NIC and peer has already been deleted, free it now. */ - if (nic->peer_deleted) { - for (i = 0; i < queues; i++) { - qemu_free_net_client(qemu_get_subqueue(nic, i)->peer); + for (i = 0; i < queues; i++) { + NetClientState *nc = qemu_get_subqueue(nic, i); + /* If this is a peer NIC and peer has already been deleted, free it now. */ + if (nic->peer_deleted) { + qemu_free_net_client(nc->peer); + } else if (nc->peer) { + /* if there are RX packets pending, complete them */ + qemu_purge_queued_packets(nc->peer); } }