From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mx0a-001b2d01.pphosted.com ([148.163.156.1]:13758 "EHLO mx0a-001b2d01.pphosted.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1727122AbfKOLjl (ORCPT ); Fri, 15 Nov 2019 06:39:41 -0500 Received: from pps.filterd (m0098393.ppops.net [127.0.0.1]) by mx0a-001b2d01.pphosted.com (8.16.0.42/8.16.0.42) with SMTP id xAFBX6n3033372 for ; Fri, 15 Nov 2019 06:39:40 -0500 Received: from e06smtp03.uk.ibm.com (e06smtp03.uk.ibm.com [195.75.94.99]) by mx0a-001b2d01.pphosted.com with ESMTP id 2w9nse40qk-1 (version=TLSv1.2 cipher=AES256-GCM-SHA384 bits=256 verify=NOT) for ; Fri, 15 Nov 2019 06:39:40 -0500 Received: from localhost by e06smtp03.uk.ibm.com with IBM ESMTP SMTP Gateway: Authorized Use Only! Violators will be prosecuted for from ; Fri, 15 Nov 2019 11:39:38 -0000 From: Karsten Graul Subject: [PATCH net] net/smc: fix fastopen for non-blocking connect() Date: Fri, 15 Nov 2019 12:39:30 +0100 Message-Id: <20191115113930.38684-1-kgraul@linux.ibm.com> Sender: linux-s390-owner@vger.kernel.org List-ID: To: davem@davemloft.net Cc: netdev@vger.kernel.org, linux-s390@vger.kernel.org, heiko.carstens@de.ibm.com, raspl@linux.ibm.com, ubraun@linux.ibm.com From: Ursula Braun FASTOPEN does not work with SMC-sockets. Since SMC allows fallback to TCP native during connection start, the FASTOPEN setsockopts trigger this fallback, if the SMC-socket is still in state SMC_INIT. But if a FASTOPEN setsockopt is called after a non-blocking connect(), this is broken, and fallback does not make sense. This change complements commit cd2063604ea6 ("net/smc: avoid fallback in case of non-blocking connect") and fixes the syzbot reported problem "WARNING in smc_unhash_sk". Reported-by: syzbot+8488cc4cf1c9e09b8b86@syzkaller.appspotmail.com Fixes: e1bbdd570474 ("net/smc: reduce sock_put() for fallback sockets") Signed-off-by: Ursula Braun Signed-off-by: Karsten Graul --- net/smc/af_smc.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/net/smc/af_smc.c b/net/smc/af_smc.c index 8edf1619f0e4..737b49909a7a 100644 --- a/net/smc/af_smc.c +++ b/net/smc/af_smc.c @@ -1732,7 +1732,7 @@ static int smc_setsockopt(struct socket *sock, int level, int optname, case TCP_FASTOPEN_KEY: case TCP_FASTOPEN_NO_COOKIE: /* option not supported by SMC */ - if (sk->sk_state == SMC_INIT) { + if (sk->sk_state == SMC_INIT && !smc->connect_nonblock) { smc_switch_to_fallback(smc); smc->fallback_rsn = SMC_CLC_DECL_OPTUNSUPP; } else { -- 2.17.1