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=-4.0 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, MAILING_LIST_MULTI,SIGNED_OFF_BY,SPF_PASS 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 1201CC169C4 for ; Mon, 11 Feb 2019 20:44:58 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id DEB12218A4 for ; Mon, 11 Feb 2019 20:44:57 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1727708AbfBKUo4 (ORCPT ); Mon, 11 Feb 2019 15:44:56 -0500 Received: from shards.monkeyblade.net ([23.128.96.9]:43942 "EHLO shards.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726940AbfBKUoz (ORCPT ); Mon, 11 Feb 2019 15:44:55 -0500 Received: from localhost (unknown [IPv6:2601:601:9f80:35cd::bf5]) (using TLSv1 with cipher AES256-SHA (256/256 bits)) (Client did not present a certificate) (Authenticated sender: davem-davemloft) by shards.monkeyblade.net (Postfix) with ESMTPSA id F15AA14BFB577; Mon, 11 Feb 2019 12:44:54 -0800 (PST) Date: Mon, 11 Feb 2019 12:44:54 -0800 (PST) Message-Id: <20190211.124454.57457094563963413.davem@davemloft.net> To: edumazet@google.com Cc: netdev@vger.kernel.org, eric.dumazet@gmail.com, petrm@mellanox.com, idosch@mellanox.com, roopa@cumulusnetworks.com, sbrivio@redhat.com Subject: Re: [PATCH net] vxlan: test dev->flags & IFF_UP before calling netif_rx() From: David Miller In-Reply-To: <20190207202738.155940-1-edumazet@google.com> References: <20190207202738.155940-1-edumazet@google.com> X-Mailer: Mew version 6.8 on Emacs 26.1 Mime-Version: 1.0 Content-Type: Text/Plain; charset=us-ascii Content-Transfer-Encoding: 7bit X-Greylist: Sender succeeded SMTP AUTH, not delayed by milter-greylist-4.5.12 (shards.monkeyblade.net [149.20.54.216]); Mon, 11 Feb 2019 12:44:55 -0800 (PST) Sender: netdev-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: netdev@vger.kernel.org From: Eric Dumazet Date: Thu, 7 Feb 2019 12:27:38 -0800 > netif_rx() must be called under a strict contract. > > At device dismantle phase, core networking clears IFF_UP > and flush_all_backlogs() is called after rcu grace period > to make sure no incoming packet might be in a cpu backlog > and still referencing the device. > > Most drivers call netif_rx() from their interrupt handler, > and since the interrupts are disabled at device dismantle, > netif_rx() does not have to check dev->flags & IFF_UP > > Virtual drivers do not have this guarantee, and must > therefore make the check themselves. > > Otherwise we risk use-after-free and/or crashes. > > Note this patch also fixes a small issue that came > with commit ce6502a8f957 ("vxlan: fix a use after free > in vxlan_encap_bypass"), since the dev->stats.rx_dropped > change was done on the wrong device. > > Fixes: d342894c5d2f ("vxlan: virtual extensible lan") > Fixes: ce6502a8f957 ("vxlan: fix a use after free in vxlan_encap_bypass") > Signed-off-by: Eric Dumazet Applied and queued up for -stable.