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 X-Spam-Level: X-Spam-Status: No, score=-7.0 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, INCLUDES_PATCH,MAILING_LIST_MULTI,SIGNED_OFF_BY,SPF_PASS,URIBL_BLOCKED autolearn=ham autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id A73F1C43381 for ; Sat, 16 Mar 2019 06:34:07 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 6F1D5218FC for ; Sat, 16 Mar 2019 06:34:07 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1726004AbfCPG2b (ORCPT ); Sat, 16 Mar 2019 02:28:31 -0400 Received: from szxga07-in.huawei.com ([45.249.212.35]:49880 "EHLO huawei.com" rhost-flags-OK-OK-OK-FAIL) by vger.kernel.org with ESMTP id S1725879AbfCPG2b (ORCPT ); Sat, 16 Mar 2019 02:28:31 -0400 Received: from DGGEMS414-HUB.china.huawei.com (unknown [172.30.72.59]) by Forcepoint Email with ESMTP id 384597E1B71F559A44C6; Sat, 16 Mar 2019 14:28:28 +0800 (CST) Received: from [127.0.0.1] (10.184.225.177) by DGGEMS414-HUB.china.huawei.com (10.3.19.214) with Microsoft SMTP Server id 14.3.408.0; Sat, 16 Mar 2019 14:28:17 +0800 Subject: Re: [PATCH v2] vxlan: remove the redundant gro_cells_destroy() calling. To: Stefano Brivio CC: Eric Dumazet , David Miller , , , , , , , , References: <20190315162824.732b18ac@elisabeth> <005ad387-8d51-561e-a5b9-8e851e03d5e9@gmail.com> <20190315.110249.648596993203657814.davem@davemloft.net> <20190315220841.078e15b7@elisabeth> <1b09614f-e500-f59b-5f1e-f896c3fd39ac@gmail.com> <20190315230457.094e2939@elisabeth> <308992f9-5c45-ea0c-7265-82c6976be45f@huawei.com> <20190316064507.10373066@elisabeth> From: Zhiqiang Liu Message-ID: <94934308-c086-fae9-6a7b-608f507afefe@huawei.com> Date: Sat, 16 Mar 2019 14:27:47 +0800 User-Agent: Mozilla/5.0 (Windows NT 6.1; WOW64; rv:60.0) Gecko/20100101 Thunderbird/60.5.0 MIME-Version: 1.0 In-Reply-To: <20190316064507.10373066@elisabeth> Content-Type: text/plain; charset="gbk" Content-Transfer-Encoding: 7bit X-Originating-IP: [10.184.225.177] X-CFilter-Loop: Reflected Sender: netdev-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: netdev@vger.kernel.org > On Sat, 16 Mar 2019 13:24:39 +0800 > Zhiqiang Liu wrote: > >> I have updated the commit message as suggested by Eric. Even though I have read >> Documentation/networking/netdev-FAQ.rst as you mentioned. I am now still a little >> confused about the subject-prefix of v3 (net or net-next). > > It's "net": this is a (likely critical) fix. > >> And David Miller saied the net-next tree is CLOSED. > > Right, but this is not for net-next anymore, given what Eric found. > >> Could you help me check whether the following v3 patch is ok? >> >> >> Subject: [PATCH net v3] vxlan: remove the redundant gro_cells_destroy() calling. > > This one. And it's not just redundant, so maybe something like: > > "[PATCH net v3] vxlan: Don't call gro_cells_destroy() before > device is unregistered" > >> OR >> Subject: [PATCH net-next v3] vxlan: remove the redundant gro_cells_destroy() calling. >> >> Commit ad6c9986bcb62 ("vxlan: Fix GRO cells race condition between >> receive and link delete") fixed a race condition for the typical case a vxlan >> device is dismantled from the current netns. But if a netns is dismantled, >> vxlan_destroy_tunnels() is called to schedule a unregister_netdevice_queue() >> of all the vxlan tunnels that are related to this netns. >> >> In vxlan_destroy_tunnels(), gro_cells_destroy() is called and finished before >> unregister_netdevice_queue(). This means that the gro_cells_destroy() call is >> done too soon, for the same reasons explained in above commit. >> >> So we need to fully respect the RCU rules, and thus must remove the >> gro_cells_destroy() call or risk use after-free. >> >> Fixes: 58ce31cca1ff ("vxlan: GRO support at tunnel layer") >> Signed-off-by: Suanming.Mou >> Suggested-by: Eric Dumazet >> Reviewed-by: Stefano Brivio >> Reviewed-by: Zhiqiang Liu >> --- >> V1->V2: > > This will actually be v3. > >> - update the commit message suggeted by Eric Dumazet >> - update Fixes: tag >> >> drivers/net/vxlan.c | 4 +--- >> 1 file changed, 1 insertion(+), 3 deletions(-) >> >> diff --git a/drivers/net/vxlan.c b/drivers/net/vxlan.c >> index 077f1b9f2761..d76dfed8d9bb 100644 >> --- a/drivers/net/vxlan.c >> +++ b/drivers/net/vxlan.c >> @@ -4335,10 +4335,8 @@ static void vxlan_destroy_tunnels(struct net *net, struct list_head *head) >> /* If vxlan->dev is in the same netns, it has already been added >> * to the list by the previous loop. >> */ >> - if (!net_eq(dev_net(vxlan->dev), net)) { >> - gro_cells_destroy(&vxlan->gro_cells); >> + if (!net_eq(dev_net(vxlan->dev), net)) >> unregister_netdevice_queue(vxlan->dev, head); >> - } >> } >> >> for (h = 0; h < PORT_HASH_SIZE; ++h) > > Looks good to me, you can keep my Reviewed-by: tag for v3. Thanks! > Thank you for your patience to reply. And thanks for Eric and David Miller again. I will make the v3 as your suggestion.