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 F3C23C433EF for ; Mon, 23 May 2022 13:25:59 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S236241AbiEWNZ5 (ORCPT ); Mon, 23 May 2022 09:25:57 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:53694 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S236182AbiEWNZu (ORCPT ); Mon, 23 May 2022 09:25:50 -0400 Received: from corp-front07-corp.i.nease.net (corp-front07-corp.i.nease.net [59.111.134.157]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 158763F897; Mon, 23 May 2022 06:25:43 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=corp.netease.com; s=s210401; h=Received:From:To:Cc:Subject: Date:Message-Id:In-Reply-To:References:MIME-Version: Content-Transfer-Encoding; bh=vij71P4VVuIOT3OaBmgG9nyixyx+SJjaYA EmsqnR2z4=; b=slTj/MFPoEkYxC1IJGveqxkL7MXNNctro7q78PgCf3H08BFKJK RlTUnGKOuSoJUlyoyD4orxI88wtM+hrdHvTy2tErADcH6cZDJvsT5hI0g6iXxN1o iZDMEvaxnr3xPIVBTLdxRbcFtYktaFQi5mV9UNnGfwZMPUNCfjiJbrypQ= Received: from pubt1-k8s74.yq.163.org (unknown [115.238.122.38]) by corp-front07-corp.i.nease.net (Coremail) with SMTP id nRDICgA31BJLi4tii9xgAA--.34974S2; Mon, 23 May 2022 21:25:31 +0800 (HKT) From: liuyacan@corp.netease.com To: kgraul@linux.ibm.com Cc: davem@davemloft.net, edumazet@google.com, kuba@kernel.org, linux-kernel@vger.kernel.org, linux-s390@vger.kernel.org, liuyacan@corp.netease.com, netdev@vger.kernel.org, pabeni@redhat.com, ubraun@linux.ibm.com Subject: Re: [PATCH net] net/smc: fix listen processing for SMC-Rv2 Date: Mon, 23 May 2022 21:25:31 +0800 Message-Id: <20220523132531.2419421-1-liuyacan@corp.netease.com> X-Mailer: git-send-email 2.20.1 In-Reply-To: References: MIME-Version: 1.0 Content-Transfer-Encoding: 8bit X-CM-TRANSID: nRDICgA31BJLi4tii9xgAA--.34974S2 X-Coremail-Antispam: 1UD129KBjvJXoW7Ar1fZr45uFWxWw15KFWrAFb_yoW8tr45pF W8AF4SkFWDt3WFywsFqF1rXr4Fyryrtr9xWr9xJrs5C3s0vr95ArW8Xry5uFZ7ZF43K3Wx Zr48ZrWfZw1DAaDanT9S1TB71UUUUU7qnTZGkaVYY2UrUUUUjbIjqfuFe4nvWSU5nxnvy2 9KBjDU0xBIdaVrnRJUUUXjb7IF0VCFI7km07C26c804VAKzcIF0wAFF20E14v26r4j6ryU M7CY07I20VC2zVCF04k26cxKx2IYs7xG6rWj6s0DM7CIcVAFz4kK6r1j6r18M28lY4IEw2 IIxxk0rwA2F7IY1VAKz4vEj48ve4kI8wA2z4x0Y4vE2Ix0cI8IcVAFwI0_tr0E3s1l84AC jcxK6xIIjxv20xvEc7CjxVAFwI0_Cr1j6rxdM28EF7xvwVC2z280aVAFwI0_GcCE3s1l84 ACjcxK6I8E87Iv6xkF7I0E14v26rxl6s0DM2kK67ZEXf0FJ3sC6x9vy-n0Xa0_Xr1Utr1k JwI_Jr4ln4vEF7Iv6F18KVAqrcv_GVWUtr1rJF1ln4vE4IxY62xKV4CY8xCE548m6r4UJr yUGwAa7VCY0VAaVVAqrcv_Jw1UWr13M2AIxVAIcxkEcVAq07x20xvEncxIr21l57IF6s8C jcxG0xyl5I8CrVACY4xI64kE6c02F40Ex7xfMcIj6xIIjxv20xvE14v26r106r15McIj6I 8E87Iv67AKxVWUJVW8JwAm72CE4IkC6x0Yz7v_Jr0_Gr1lF7xvr2IYc2Ij64vIr41lF7I2 1c0EjII2zVCS5cI20VAGYxC7M4IIrI8v6xkF7I0E8cxan2IY04v7M4kE6xkIj40Ew7xC0w CjxxvEw4Wlc2IjII80xcxEwVAKI48JMxAIw28IcxkI7VAKI48JMxCjnVAK0II2c7xJMxC2 0s026xCaFVCjc4AY6r1j6r4UMxCIbckI1I0E14v26r1Y6r17MxCIbVAxMI8I3I0E5I8CrV AFwI0_Jr0_Jr4lx2IqxVCjr7xvwVAFwI0_JrI_JrWlx4CE17CEb7AF67AKxVWUtVW8ZwCI c40Y0x0EwIxGrwCI42IY6xIIjxv20xvE14v26r1j6r1xMIIF0xvE2Ix0cI8IcVCY1x0267 AKxVW8JVWxJwCI42IY6xAIw20EY4v20xvaj40_Jr0_JF4lIxAIcVC2z280aVAFwI0_Gr0_ Cr1lIxAIcVC2z280aVCY1x0267AKxVW8JVW8JrUvcSsGvfC2KfnxnUUI43ZEXa7sRRhSdJ UUUUU== X-CM-SenderInfo: 5olx5txfdqquhrush05hwht23hof0z/1tbiBQAPCVt760qFUgAXsC Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org > >>> From: liuyacan > >>> > >>> In the process of checking whether RDMAv2 is available, the current > >>> implementation first sets ini->smcrv2.ib_dev_v2, and then allocates > >>> smc buf desc, but the latter may fail. Unfortunately, the caller > >>> will only check the former. In this case, a NULL pointer reference > >>> will occur in smc_clc_send_confirm_accept() when accessing > >>> conn->rmb_desc. > >>> > >>> This patch does two things: > >>> 1. Use the return code to determine whether V2 is available. > >>> 2. If the return code is NODEV, continue to check whether V1 is > >>> available. > >>> > >>> Fixes: e49300a6bf62 ("net/smc: add listen processing for SMC-Rv2") > >>> Signed-off-by: liuyacan > >>> --- > >> > >> I am not happy with this patch. You are right that this is a problem, > >> but the fix should be much simpler: set ini->smcrv2.ib_dev_v2 = NULL in > >> smc_find_rdma_v2_device_serv() after the not_found label, just like it is > >> done in a similar way for the ISM device in smc_find_ism_v1_device_serv(). > >> > >> Your patch changes many more things, and beside that you eliminated the calls > >> to smc_find_ism_store_rc() completely, which is not correct. > >> > >> Since your patch was already applied (btw. 3:20 hours after you submitted it), > >> please revert it and resend. Thank you. > > > > I also have considered this way, one question is that do we need to do more roll > > back work before V1 check? > > > > Specifically, In smc_find_rdma_v2_device_serv(), there are the following steps: > > > > 1. smc_listen_rdma_init() > > 1.1 smc_conn_create() > > 1.2 smc_buf_create() --> may fail > > 2. smc_listen_rdma_reg() --> may fail > > > > When later steps fail, Do we need to roll back previous steps? > > That is a good question and I think that is a different problem for another patch. > smc_listen_rdma_init() maybe should call smc_conn_abort() similar to what smc_listen_ism_init() > does in this situation. And when smc_listen_rdma_reg() fails ... hmm we need to think about this. > > We will also discuss this here in our team. Ok, I will revert this patch and resend a simpler one. Thank you.