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=BAYES_00, HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI,SIGNED_OFF_BY,SPF_HELO_NONE, SPF_PASS autolearn=no 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 74F3CC433E2 for ; Tue, 1 Sep 2020 20:01:38 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 4A553207D3 for ; Tue, 1 Sep 2020 20:01:38 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1732782AbgIAUBf (ORCPT ); Tue, 1 Sep 2020 16:01:35 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:39758 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1732069AbgIAUBd (ORCPT ); Tue, 1 Sep 2020 16:01:33 -0400 Received: from shards.monkeyblade.net (shards.monkeyblade.net [IPv6:2620:137:e000::1:9]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 59757C061244; Tue, 1 Sep 2020 13:01:33 -0700 (PDT) Received: from localhost (unknown [IPv6:2601:601:9f00:477::3d5]) (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 C708B13649A5A; Tue, 1 Sep 2020 12:44:43 -0700 (PDT) Date: Tue, 01 Sep 2020 13:01:27 -0700 (PDT) Message-Id: <20200901.130127.236989626732311083.davem@davemloft.net> To: rkovhaev@gmail.com Cc: kuba@kernel.org, netdev@vger.kernel.org, bpf@vger.kernel.org, linux-kernel@vger.kernel.org, gregkh@linuxfoundation.org Subject: Re: [PATCH] veth: fix memory leak in veth_newlink() From: David Miller In-Reply-To: <20200830131336.275844-1-rkovhaev@gmail.com> References: <20200830131336.275844-1-rkovhaev@gmail.com> X-Mailer: Mew version 6.8 on Emacs 26.3 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 [2620:137:e000::1:9]); Tue, 01 Sep 2020 12:44:44 -0700 (PDT) Sender: netdev-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: netdev@vger.kernel.org From: Rustam Kovhaev Date: Sun, 30 Aug 2020 06:13:36 -0700 > when register_netdevice(dev) fails we should check whether struct > veth_rq has been allocated via ndo_init callback and free it, because, > depending on the code path, register_netdevice() might not call > priv_destructor() callback > > Reported-and-tested-by: syzbot+59ef240dd8f0ed7598a8@syzkaller.appspotmail.com > Link: https://syzkaller.appspot.com/bug?extid=59ef240dd8f0ed7598a8 > Signed-off-by: Rustam Kovhaev I think I agree with Toshiaki here. There is no reason why the rollback_registered() path of register_netdevice() should behave differently from the normal control flow. Any code path that invokes ->ndo_uninit() should probably also invoke the priv destructor. The question is why does the err_uninit: label of register_netdevice behave differently from rollback_registered()? If there is a reason, it should be documented in a comment or similar. If it is wrong, it should be corrected.