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 Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id 4530FC433EF for ; Mon, 22 Nov 2021 03:19:23 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S230258AbhKVDW1 (ORCPT ); Sun, 21 Nov 2021 22:22:27 -0500 Received: from out30-132.freemail.mail.aliyun.com ([115.124.30.132]:48837 "EHLO out30-132.freemail.mail.aliyun.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S229775AbhKVDW1 (ORCPT ); Sun, 21 Nov 2021 22:22:27 -0500 X-Alimail-AntiSpam: AC=PASS;BC=-1|-1;BR=01201311R411e4;CH=green;DM=||false|;DS=||;FP=0|-1|-1|-1|0|-1|-1|-1;HT=e01e04426;MF=tonylu@linux.alibaba.com;NM=1;PH=DS;RN=5;SR=0;TI=SMTPD_---0UxbMwFb_1637551159; Received: from localhost(mailfrom:tonylu@linux.alibaba.com fp:SMTPD_---0UxbMwFb_1637551159) by smtp.aliyun-inc.com(127.0.0.1); Mon, 22 Nov 2021 11:19:20 +0800 Date: Mon, 22 Nov 2021 11:19:18 +0800 From: Tony Lu To: Daxing Guo Cc: netdev@vger.kernel.org, chenzhe@huawei.com, linux-s390@vger.kernel.org, greg@kroah.com Subject: Re: [PATCH] net/smc: loop in smc_listen Message-ID: Reply-To: Tony Lu References: <20211120075451.16764-1-guodaxing@huawei.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20211120075451.16764-1-guodaxing@huawei.com> Precedence: bulk List-ID: X-Mailing-List: netdev@vger.kernel.org On Sat, Nov 20, 2021 at 03:54:51PM +0800, Daxing Guo wrote: > From: Guo DaXing > > The kernel_listen function in smc_listen will fail when all the available > ports are occupied. At this point smc->clcsock->sk->sk_data_ready has > been changed to smc_clcsock_data_ready. When we call smc_listen again, > now both smc->clcsock->sk->sk_data_ready and smc->clcsk_data_ready point > to the smc_clcsock_data_ready function. > > The smc_clcsock_data_ready() function calls lsmc->clcsk_data_ready which > now points to itself resulting in an infinite loop. > > This patch restores smc->clcsock->sk->sk_data_ready with the old value. Hi Guo, This indeed seems to be an issue. When listen fails, the original clcsock's sk_data_ready overwrites by smc_clcsock_data_ready and can't be recovered. I will also test it in my environment, thanks. Cheers, Tony Lu > > Signed-off-by: Guo DaXing > --- > net/smc/af_smc.c | 4 +++- > 1 file changed, 3 insertions(+), 1 deletion(-) > > diff --git a/net/smc/af_smc.c b/net/smc/af_smc.c > index 59284da9116d..078f5edf6d4d 100644 > --- a/net/smc/af_smc.c > +++ b/net/smc/af_smc.c > @@ -2120,8 +2120,10 @@ static int smc_listen(struct socket *sock, int backlog) > smc->clcsock->sk->sk_user_data = > (void *)((uintptr_t)smc | SK_USER_DATA_NOCOPY); > rc = kernel_listen(smc->clcsock, backlog); > - if (rc) > + if (rc) { > + smc->clcsock->sk->sk_data_ready = smc->clcsk_data_ready; > goto out; > + } > sk->sk_max_ack_backlog = backlog; > sk->sk_ack_backlog = 0; > sk->sk_state = SMC_LISTEN; > -- > 2.20.1