| Message ID | 20230619065209.442185-1-anisinha@redhat.com |
|---|---|
| State | New |
| Headers | show |
| Series | vhost-vdpa: do not cleanup the vdpa/vhost-net structures if peer nic is present | expand |
diff --git a/net/vhost-vdpa.c b/net/vhost-vdpa.c index 37cdc84562..ef9dd0afdb 100644 --- a/net/vhost-vdpa.c +++ b/net/vhost-vdpa.c @@ -185,6 +185,14 @@ static void vhost_vdpa_cleanup(NetClientState *nc) { VhostVDPAState *s = DO_UPCAST(VhostVDPAState, nc, nc); + /* + * If a peer NIC is attached, do not cleanup anything. + * Cleanup will happen as a part of qemu_cleanup() -> net_cleanup() + * when the guest is shutting down. + */ + if (nc->peer && nc->peer->info->type == NET_CLIENT_DRIVER_NIC) { + return; + } qemu_vfree(s->cvq_cmd_out_buffer); qemu_vfree(s->status); if (s->vhost_net) {
When a peer nic is still attached to the vdpa backend, it is too early to free up the vhost-net and vdpa structures. If these structures are freed here, then QEMU crashes when the guest is being shut down. The following call chain would result in an assertion failure since the pointer returned from vhost_vdpa_get_vhost_net() would be NULL: do_vm_stop() -> vm_state_notify() -> virtio_set_status() -> virtio_net_vhost_status() -> get_vhost_net(). Therefore, we defer freeing up the structures until at guest shutdown time when qemu_cleanup() calls net_cleanup() which then calls qemu_del_net_client() which would eventually call vhost_vdpa_cleanup() again to free up the structures. This time, the loop in net_cleanup() ensures that vhost_vdpa_cleanup() will be called one last time when all the peer nics are detached and freed. All unit tests pass with this change. CC: imammedo@redhat.com CC: jusual@redhat.com CC: mst@redhat.com Resolves: https://bugzilla.redhat.com/show_bug.cgi?id=2128929 Signed-off-by: Ani Sinha <anisinha@redhat.com> --- net/vhost-vdpa.c | 8 ++++++++ 1 file changed, 8 insertions(+)