From mboxrd@z Thu Jan 1 00:00:00 1970 From: Stefan Hajnoczi Subject: [PATCH] vhost/vsock: fix reset orphans race with close timeout Date: Thu, 6 Dec 2018 19:14:34 +0000 Message-ID: <20181206191434.15448-1-stefanha@redhat.com> Mime-Version: 1.0 Content-Transfer-Encoding: 8bit Cc: "Michael S. Tsirkin" , netdev@vger.kernel.org, Maximilian Riemensberger , Graham Whaley , Stefan Hajnoczi To: kvm@vger.kernel.org Return-path: Received: from mx1.redhat.com ([209.132.183.28]:32982 "EHLO mx1.redhat.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1725908AbeLFTPd (ORCPT ); Thu, 6 Dec 2018 14:15:33 -0500 Sender: netdev-owner@vger.kernel.org List-ID: If a local process has closed a connected socket and hasn't received a RST packet yet, then the socket remains in the table until a timeout expires. When a vhost_vsock instance is released with the timeout still pending, the socket is never freed because vhost_vsock has already set the SOCK_DONE flag. Check if the close timer is pending and let it close the socket. This prevents the race which can leak sockets. Reported-by: Maximilian Riemensberger Cc: Graham Whaley Signed-off-by: Stefan Hajnoczi --- drivers/vhost/vsock.c | 22 +++++++++++++++------- 1 file changed, 15 insertions(+), 7 deletions(-) diff --git a/drivers/vhost/vsock.c b/drivers/vhost/vsock.c index 34bc3ab40c6d..731e2ea2aeca 100644 --- a/drivers/vhost/vsock.c +++ b/drivers/vhost/vsock.c @@ -563,13 +563,21 @@ static void vhost_vsock_reset_orphans(struct sock *sk) * executing. */ - if (!vhost_vsock_get(vsk->remote_addr.svm_cid)) { - sock_set_flag(sk, SOCK_DONE); - vsk->peer_shutdown = SHUTDOWN_MASK; - sk->sk_state = SS_UNCONNECTED; - sk->sk_err = ECONNRESET; - sk->sk_error_report(sk); - } + /* If the peer is still valid, no need to reset connection */ + if (vhost_vsock_get(vsk->remote_addr.svm_cid)) + return; + + /* If the close timeout is pending, let it expire. This avoids races + * with the timeout callback. + */ + if (vsk->close_work_scheduled) + return; + + sock_set_flag(sk, SOCK_DONE); + vsk->peer_shutdown = SHUTDOWN_MASK; + sk->sk_state = SS_UNCONNECTED; + sk->sk_err = ECONNRESET; + sk->sk_error_report(sk); } static int vhost_vsock_dev_release(struct inode *inode, struct file *file) -- 2.19.2