Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752672AbdDLDOm (ORCPT ); Tue, 11 Apr 2017 23:14:42 -0400 Received: from mail-pg0-f66.google.com ([74.125.83.66]:35923 "EHLO mail-pg0-f66.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752046AbdDLDOj (ORCPT ); Tue, 11 Apr 2017 23:14:39 -0400 From: "R. Parameswaran" X-Google-Original-From: "R. Parameswaran" Date: Tue, 11 Apr 2017 20:14:37 -0700 (PDT) X-X-Sender: nelson@nelson51.eng.vyatta.net To: netdev@vger.kernel.org cc: kleptog@svana.org, jchapman@katalix.com, davem@redhat.com, nprachan@brocade.com, rshearma@brocade.com, stephen@networkplumber.org, sdietric@brocade.com, ciwillia@brocade.com, lboccass@brocade.com, dfawcus@brocade.com, bhong@brocade.com, jblunck@brocade.com, linux-kernel@vger.kernel.org Subject: [PATCH net-next v1 1/1] L2TP device MTU setup - tunnel socket needs a lock Message-ID: User-Agent: Alpine 2.11 (DEB 23 2013-08-11) MIME-Version: 1.0 Content-Type: TEXT/PLAIN; charset=US-ASCII Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 2047 Lines: 54 The MTU overhead calculation in L2TP device set-up merged via commit b784e7ebfce8cfb16c6f95e14e8532d0768ab7ff needs to be adjusted to lock the tunnel socket while referencing the sub-data structures to derive the socket's IP overhead. --- include/linux/net.h | 2 +- net/l2tp/l2tp_eth.c | 2 ++ net/socket.c | 2 +- 3 files changed, 4 insertions(+), 2 deletions(-) diff --git a/include/linux/net.h b/include/linux/net.h index a42fab2..abcfa46 100644 --- a/include/linux/net.h +++ b/include/linux/net.h @@ -298,7 +298,7 @@ int kernel_sendpage(struct socket *sock, struct page *page, int offset, int kernel_sock_ioctl(struct socket *sock, int cmd, unsigned long arg); int kernel_sock_shutdown(struct socket *sock, enum sock_shutdown_cmd how); -/* Following routine returns the IP overhead imposed by a socket. */ +/* Routine returns the IP overhead imposed by a (caller-protected) socket. */ u32 kernel_sock_ip_overhead(struct sock *sk); #define MODULE_ALIAS_NETPROTO(proto) \ diff --git a/net/l2tp/l2tp_eth.c b/net/l2tp/l2tp_eth.c index 138566a..b722d55 100644 --- a/net/l2tp/l2tp_eth.c +++ b/net/l2tp/l2tp_eth.c @@ -225,7 +225,9 @@ static void l2tp_eth_adjust_mtu(struct l2tp_tunnel *tunnel, dev->needed_headroom += session->hdr_len; return; } + lock_sock(tunnel->sock); l3_overhead = kernel_sock_ip_overhead(tunnel->sock); + release_sock(tunnel->sock); if (l3_overhead == 0) { /* L3 Overhead couldn't be identified, this could be * because tunnel->sock was NULL or the socket's diff --git a/net/socket.c b/net/socket.c index eea9970..c2564eb 100644 --- a/net/socket.c +++ b/net/socket.c @@ -3360,7 +3360,7 @@ EXPORT_SYMBOL(kernel_sock_shutdown); /* This routine returns the IP overhead imposed by a socket i.e. * the length of the underlying IP header, depending on whether * this is an IPv4 or IPv6 socket and the length from IP options turned - * on at the socket. + * on at the socket. Assumes that the caller has a lock on the socket. */ u32 kernel_sock_ip_overhead(struct sock *sk) { -- 2.1.4