From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-3.8 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, MAILING_LIST_MULTI,SIGNED_OFF_BY,SPF_HELO_NONE,SPF_PASS,URIBL_BLOCKED autolearn=no autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id C16DDC0650F for ; Mon, 5 Aug 2019 20:25:24 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 985F9208E3 for ; Mon, 5 Aug 2019 20:25:24 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1730589AbfHEUZX (ORCPT ); Mon, 5 Aug 2019 16:25:23 -0400 Received: from shards.monkeyblade.net ([23.128.96.9]:33728 "EHLO shards.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1727802AbfHEUZX (ORCPT ); Mon, 5 Aug 2019 16:25:23 -0400 Received: from localhost (unknown [IPv6:2601:601:9f80:35cd::d71]) (using TLSv1 with cipher AES256-SHA (256/256 bits)) (Client did not present a certificate) (Authenticated sender: davem-davemloft) by shards.monkeyblade.net (Postfix) with ESMTPSA id CC269154319A7; Mon, 5 Aug 2019 13:25:22 -0700 (PDT) Date: Mon, 05 Aug 2019 13:25:22 -0700 (PDT) Message-Id: <20190805.132522.1261096972203874719.davem@davemloft.net> To: kgraul@linux.ibm.com Cc: netdev@vger.kernel.org, linux-s390@vger.kernel.org, gor@linux.ibm.com, heiko.carstens@de.ibm.com, raspl@linux.ibm.com, ubraun@linux.ibm.com Subject: Re: [PATCH net] net/smc: avoid fallback in case of non-blocking connect From: David Miller In-Reply-To: <20190802084750.5518-1-kgraul@linux.ibm.com> References: <20190802084750.5518-1-kgraul@linux.ibm.com> X-Mailer: Mew version 6.8 on Emacs 26.1 Mime-Version: 1.0 Content-Type: Text/Plain; charset=us-ascii Content-Transfer-Encoding: 7bit X-Greylist: Sender succeeded SMTP AUTH, not delayed by milter-greylist-4.5.12 (shards.monkeyblade.net [149.20.54.216]); Mon, 05 Aug 2019 13:25:23 -0700 (PDT) Sender: netdev-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: netdev@vger.kernel.org From: Karsten Graul Date: Fri, 2 Aug 2019 10:47:50 +0200 > From: Ursula Braun > > FASTOPEN is not possible with SMC. sendmsg() with msg_flag MSG_FASTOPEN > triggers a fallback to TCP if the socket is in state SMC_INIT. > But if a nonblocking connect is already started, fallback to TCP > is no longer possible, even though the socket may still be in state > SMC_INIT. > And if a nonblocking connect is already started, a listen() call > does not make sense. > > Reported-by: syzbot+bd8cc73d665590a1fcad@syzkaller.appspotmail.com > Fixes: 50717a37db032 ("net/smc: nonblocking connect rework") > Signed-off-by: Ursula Braun > Signed-off-by: Karsten Graul Applied and queued up for -stable.