From patchwork Mon Jun 22 15:15:00 2015 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Luis Henriques X-Patchwork-Id: 487234 Return-Path: X-Original-To: incoming@patchwork.ozlabs.org Delivered-To: patchwork-incoming@bilbo.ozlabs.org Received: from huckleberry.canonical.com (huckleberry.canonical.com [91.189.94.19]) by ozlabs.org (Postfix) with ESMTP id CE8BD14028E; Tue, 23 Jun 2015 01:15:13 +1000 (AEST) Received: from localhost ([127.0.0.1] helo=huckleberry.canonical.com) by huckleberry.canonical.com with esmtp (Exim 4.76) (envelope-from ) id 1Z73RG-0006rk-Fe; Mon, 22 Jun 2015 15:15:10 +0000 Received: from youngberry.canonical.com ([91.189.89.112]) by huckleberry.canonical.com with esmtp (Exim 4.76) (envelope-from ) id 1Z73R7-0006mD-IO for kernel-team@lists.ubuntu.com; Mon, 22 Jun 2015 15:15:01 +0000 Received: from 1.general.henrix.uk.vpn ([10.172.192.212] helo=localhost) by youngberry.canonical.com with esmtpsa (TLS1.0:RSA_AES_128_CBC_SHA1:16) (Exim 4.76) (envelope-from ) id 1Z73R7-0007zQ-CN; Mon, 22 Jun 2015 15:15:01 +0000 From: Luis Henriques To: Eric Dumazet Subject: [3.16.y-ckt stable] Patch "udp: fix behavior of wrong checksums" has been added to staging queue Date: Mon, 22 Jun 2015 16:15:00 +0100 Message-Id: <1434986100-26553-1-git-send-email-luis.henriques@canonical.com> X-Mailer: git-send-email 2.1.4 X-Extended-Stable: 3.16 Cc: Willem de Bruijn , "David S. Miller" , kernel-team@lists.ubuntu.com X-BeenThere: kernel-team@lists.ubuntu.com X-Mailman-Version: 2.1.14 Precedence: list List-Id: Kernel team discussions List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , MIME-Version: 1.0 Errors-To: kernel-team-bounces@lists.ubuntu.com Sender: kernel-team-bounces@lists.ubuntu.com This is a note to let you know that I have just added a patch titled udp: fix behavior of wrong checksums to the linux-3.16.y-queue branch of the 3.16.y-ckt extended stable tree which can be found at: http://kernel.ubuntu.com/git/ubuntu/linux.git/log/?h=linux-3.16.y-queue This patch is scheduled to be released in version 3.16.7-ckt14. If you, or anyone else, feels it should not be added to this tree, please reply to this email. For more information about the 3.16.y-ckt tree, see https://wiki.ubuntu.com/Kernel/Dev/ExtendedStable Thanks. -Luis ------ From 95ffa33e3c2706f1da6f2b4a695a416cf7edf759 Mon Sep 17 00:00:00 2001 From: Eric Dumazet Date: Sat, 30 May 2015 09:16:53 -0700 Subject: udp: fix behavior of wrong checksums commit beb39db59d14990e401e235faf66a6b9b31240b0 upstream. We have two problems in UDP stack related to bogus checksums : 1) We return -EAGAIN to application even if receive queue is not empty. This breaks applications using edge trigger epoll() 2) Under UDP flood, we can loop forever without yielding to other processes, potentially hanging the host, especially on non SMP. This patch is an attempt to make things better. We might in the future add extra support for rt applications wanting to better control time spent doing a recv() in a hostile environment. For example we could validate checksums before queuing packets in socket receive queue. Signed-off-by: Eric Dumazet Cc: Willem de Bruijn Signed-off-by: David S. Miller Signed-off-by: Luis Henriques --- net/ipv4/udp.c | 6 ++---- net/ipv6/udp.c | 6 ++---- 2 files changed, 4 insertions(+), 8 deletions(-) diff --git a/net/ipv4/udp.c b/net/ipv4/udp.c index 7d5a8661df76..688658dd7958 100644 --- a/net/ipv4/udp.c +++ b/net/ipv4/udp.c @@ -1356,10 +1356,8 @@ csum_copy_err: } unlock_sock_fast(sk, slow); - if (noblock) - return -EAGAIN; - - /* starting over for a new packet */ + /* starting over for a new packet, but check if we need to yield */ + cond_resched(); msg->msg_flags &= ~MSG_TRUNC; goto try_again; } diff --git a/net/ipv6/udp.c b/net/ipv6/udp.c index 7092ff78fd84..ad5891072a89 100644 --- a/net/ipv6/udp.c +++ b/net/ipv6/udp.c @@ -515,10 +515,8 @@ csum_copy_err: } unlock_sock_fast(sk, slow); - if (noblock) - return -EAGAIN; - - /* starting over for a new packet */ + /* starting over for a new packet, but check if we need to yield */ + cond_resched(); msg->msg_flags &= ~MSG_TRUNC; goto try_again; }