From patchwork Wed Feb 9 14:10:53 2022 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Wen Gu X-Patchwork-Id: 12740307 X-Patchwork-Delegate: kuba@kernel.org 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 C498EC433EF for ; Wed, 9 Feb 2022 14:11:22 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S234583AbiBIOLS (ORCPT ); Wed, 9 Feb 2022 09:11:18 -0500 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:45354 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S231311AbiBIOLR (ORCPT ); Wed, 9 Feb 2022 09:11:17 -0500 Received: from out30-133.freemail.mail.aliyun.com (out30-133.freemail.mail.aliyun.com [115.124.30.133]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id DF4B5C061355; Wed, 9 Feb 2022 06:11:18 -0800 (PST) X-Alimail-AntiSpam: AC=PASS;BC=-1|-1;BR=01201311R181e4;CH=green;DM=||false|;DS=||;FP=0|-1|-1|-1|0|-1|-1|-1;HT=e01e04426;MF=guwen@linux.alibaba.com;NM=1;PH=DS;RN=6;SR=0;TI=SMTPD_---0V4.d9qH_1644415855; Received: from e02h04404.eu6sqa(mailfrom:guwen@linux.alibaba.com fp:SMTPD_---0V4.d9qH_1644415855) by smtp.aliyun-inc.com(127.0.0.1); Wed, 09 Feb 2022 22:11:15 +0800 From: Wen Gu To: kgraul@linux.ibm.com, davem@davemloft.net, kuba@kernel.org Cc: linux-s390@vger.kernel.org, netdev@vger.kernel.org, linux-kernel@vger.kernel.org Subject: [PATCH net] net/smc: Avoid overwriting the copies of clcsock callback functions Date: Wed, 9 Feb 2022 22:10:53 +0800 Message-Id: <1644415853-46641-1-git-send-email-guwen@linux.alibaba.com> X-Mailer: git-send-email 1.8.3.1 Precedence: bulk List-ID: X-Mailing-List: netdev@vger.kernel.org X-Patchwork-Delegate: kuba@kernel.org The callback functions of clcsock will be saved and replaced during the fallback. But if the fallback happens more than once, then the copies of these callback functions will be overwritten incorrectly, resulting in a loop call issue: clcsk->sk_error_report |- smc_fback_error_report() <------------------------------| |- smc_fback_forward_wakeup() | (loop) |- clcsock_callback() (incorrectly overwritten) | |- smc->clcsk_error_report() ------------------| So this patch fixes the issue by saving these function pointers only once in the fallback and avoiding overwriting. Reported-by: syzbot+4de3c0e8a263e1e499bc@syzkaller.appspotmail.com Fixes: 341adeec9ada ("net/smc: Forward wakeup to smc socket waitqueue after fallback") Link: https://lore.kernel.org/r/0000000000006d045e05d78776f6@google.com Signed-off-by: Wen Gu --- net/smc/af_smc.c | 10 +++++++--- 1 file changed, 7 insertions(+), 3 deletions(-) diff --git a/net/smc/af_smc.c b/net/smc/af_smc.c index 8c89d0b..306d9e8c 100644 --- a/net/smc/af_smc.c +++ b/net/smc/af_smc.c @@ -667,14 +667,17 @@ static void smc_fback_error_report(struct sock *clcsk) static int smc_switch_to_fallback(struct smc_sock *smc, int reason_code) { struct sock *clcsk; + int rc = 0; mutex_lock(&smc->clcsock_release_lock); if (!smc->clcsock) { - mutex_unlock(&smc->clcsock_release_lock); - return -EBADF; + rc = -EBADF; + goto out; } clcsk = smc->clcsock->sk; + if (smc->use_fallback) + goto out; smc->use_fallback = true; smc->fallback_rsn = reason_code; smc_stat_fallback(smc); @@ -702,8 +705,9 @@ static int smc_switch_to_fallback(struct smc_sock *smc, int reason_code) smc->clcsock->sk->sk_user_data = (void *)((uintptr_t)smc | SK_USER_DATA_NOCOPY); } +out: mutex_unlock(&smc->clcsock_release_lock); - return 0; + return rc; } /* fall back during connect */