[Qemu-stable] [RFC 2/2] vhost-user: Fix userfaultfd leak

[Ilya Maximets]

'fd' received from the vhost side is never freed.
Also, everything (including 'postcopy_listen' state) should be
cleaned up on vhost cleanup.

Fixes: 46343570c06e ("vhost+postcopy: Wire up POSTCOPY_END notify")
Fixes: f82c11165ffa ("vhost+postcopy: Register shared ufd with postcopy")
Cc: address@hidden
Signed-off-by: Ilya Maximets <address@hidden>
---
 hw/virtio/vhost-user.c | 7 +++++++
 1 file changed, 7 insertions(+)

diff --git a/hw/virtio/vhost-user.c b/hw/virtio/vhost-user.c
index c442daa562..e09bed0e4a 100644
--- a/hw/virtio/vhost-user.c
+++ b/hw/virtio/vhost-user.c
@@ -1280,6 +1280,7 @@ static int vhost_user_postcopy_end(struct vhost_dev *dev, 
Error **errp)
         return ret;
     }
     postcopy_unregister_shared_ufd(&u->postcopy_fd);
+    close(u->postcopy_fd.fd);
     u->postcopy_fd.handler = NULL;
 
     trace_vhost_user_postcopy_end_exit();
@@ -1419,6 +1420,12 @@ static int vhost_user_backend_cleanup(struct vhost_dev 
*dev)
         postcopy_remove_notifier(&u->postcopy_notifier);
         u->postcopy_notifier.notify = NULL;
     }
+    u->postcopy_listen = false;
+    if (u->postcopy_fd.handler) {
+        postcopy_unregister_shared_ufd(&u->postcopy_fd);
+        close(u->postcopy_fd.fd);
+        u->postcopy_fd.handler = NULL;
+    }
     if (u->slave_fd >= 0) {
         qemu_set_fd_handler(u->slave_fd, NULL, NULL, NULL);
         close(u->slave_fd);
-- 
2.17.1