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 8E809C433F5 for ; Mon, 23 May 2022 12:13:08 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S235398AbiEWMNG (ORCPT ); Mon, 23 May 2022 08:13:06 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:46998 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S235387AbiEWMNE (ORCPT ); Mon, 23 May 2022 08:13:04 -0400 Received: from corp-front08-corp.i.nease.net (corp-front08-corp.i.nease.net [59.111.134.158]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 5EBF8BF47; Mon, 23 May 2022 05:12:59 -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=O+sTlVJiIR8kihiGkvpU/fkuVTQpcFKA68 uIDzsGL7A=; b=SSASLLNxUxaYFM75kY9gFgPvvkAj2r0WZBXoGn0kvFKQP+mSne 4a5D3S4ssesaDUu6Dy8OoF6aNXVDHxkK0rBLXu325+Ewlo2MQi/52+QI5GkpD1Oj BqVChvdHDC0GMvwr/6M6myUUUQHJPen3rg40GQXXmf+FXtJw8KfNsIiwA= Received: from pubt1-k8s74.yq.163.org (unknown [115.238.122.38]) by corp-front08-corp.i.nease.net (Coremail) with SMTP id nhDICgBXlAA9eotiqXVhAA--.7902S2; Mon, 23 May 2022 20:12:45 +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 20:12:45 +0800 Message-Id: <20220523121245.1910773-1-liuyacan@corp.netease.com> X-Mailer: git-send-email 2.20.1 In-Reply-To: <76eeb1b0-6e4f-986b-c32f-e7e4de3426a7@linux.ibm.com> References: <76eeb1b0-6e4f-986b-c32f-e7e4de3426a7@linux.ibm.com> MIME-Version: 1.0 Content-Transfer-Encoding: 8bit X-CM-TRANSID: nhDICgBXlAA9eotiqXVhAA--.7902S2 X-Coremail-Antispam: 1UD129KBjvJXoW7Ar1xXr47uFyrAr1rZrWfuFg_yoW8Ar48pF WrAF4FkFWDt3WfAanFqFyrZr4rA3yFyF1fGrZxJF4Fk3sxZr95ArWIqr1Y9FZ7Za93K3WI vFW8Z393uwn8Aa7anT9S1TB71UUUUU7qnTZGkaVYY2UrUUUUjbIjqfuFe4nvWSU5nxnvy2 9KBjDU0xBIdaVrnRJUUUJCb7IF0VCFI7km07C26c804VAKzcIF0wAFF20E14v26r4j6ryU M7CY07I20VC2zVCF04k26cxKx2IYs7xG6rWj6s0DM7CIcVAFz4kK6r1j6r18M28lY4IEw2 IIxxk0rwA2F7IY1VAKz4vEj48ve4kI8wA2z4x0Y4vE2Ix0cI8IcVAFwI0_tr0E3s1l84AC jcxK6xIIjxv20xvEc7CjxVAFwI0_GcCE3s1l84ACjcxK6I8E87Iv67AKxVW0oVCq3wA2z4 x0Y4vEx4A2jsIEc7CjxVAFwI0_GcCE3s1ln4vE1TuYJxujqTIEc-sFP3VYkVW5Jr1DJw4U KVWUGwAawVACjsI_Ar4v6c8GOVW06r1DJrWUAwAawVCFI7vE04vSzxk24VAqrcv_Gr1UXr 18M2vj6xkI62vS6c8GOVWUtr1rJFyle2I262IYc4CY6c8Ij28IcVAaY2xG8wAqjxCE34x0 Y48IcwAqx4xG64xvF2IEw4CE5I8CrVC2j2WlYx0E2Ix0cI8IcVAFwI0_JrI_JrylYx0Ex4 A2jsIE14v26r1j6r4UMcvjeVCFs4IE7xkEbVWUJVW8JwACjcxG0xvY0x0EwIxGrwACjI8F 5VA0II8E6IAqYI8I648v4I1lFIxGxcIEc7CjxVA2Y2ka0xkIwI1lw4CEc2x0rVAKj4xxMx 02cVAKzwCY0x0Ix7I2Y4AK64vIr41l42xK82IYc2Ij64vIr41l4x8a64kIII0Yj41l4I8I 3I0E4IkC6x0Yz7v_Jr0_Gr1l4IxY624lx2IqxVAqx4xG67AKxVWUJVWUGwC20s026x8Gjc xK67AKxVWUGVWUWwC2zVAF1VAY17CE14v26r1q6r43MIIYrxkI7VAKI48JMIIF0xvE2Ix0 cI8IcVAFwI0_Jr0_JF4lIxAIcVC0I7IYx2IY6xkF7I0E14v26r4j6F4UMIIF0xvE42xK8V AvwI8IcIk0rVWUJVWUCwCI42IY6I8E87Iv67AKxVW8JVWxJwCI42IY6I8E87Iv6xkF7I0E 14v26r4j6r4UJbIYCTnIWIevJa73UjIFyTuYvjTREKZWUUUUU X-CM-SenderInfo: 5olx5txfdqquhrush05hwht23hof0z/1tbiBQAPCVt760qFUgARsE 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? Thank you.