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 B6129C433FE for ; Wed, 12 Jan 2022 13:07:10 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1353380AbiALNHH (ORCPT ); Wed, 12 Jan 2022 08:07:07 -0500 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:56296 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1353370AbiALNHB (ORCPT ); Wed, 12 Jan 2022 08:07:01 -0500 Received: from mail-yb1-xb32.google.com (mail-yb1-xb32.google.com [IPv6:2607:f8b0:4864:20::b32]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 4231FC06173F for ; Wed, 12 Jan 2022 05:07:01 -0800 (PST) Received: by mail-yb1-xb32.google.com with SMTP id m6so6141672ybc.9 for ; Wed, 12 Jan 2022 05:07:01 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=google.com; s=20210112; h=mime-version:references:in-reply-to:from:date:message-id:subject:to :cc; bh=QoQdoesDidCN5z4K1TfE/oxDwd8GfagNFE2hl9gCHOY=; b=YhqAIMI3bQS2DPsI1p3C/hZfHN6j8oHqaHz8ABgNnBi+A3CzOif+9IGVT3TavEHthK 0kcKHkXdx8mGzUXPCMH0dd7TS6Mm8bhJzmu8eyez+xjrokNS+ssqsKe7Vydkm6d+h5/s sNmKgbQcjRaMPptDhSlaFwJ7PoP1M5+1V7VLLmW7RIBbhVw6XL8WHaARqJgQKYUYefNr nx64uE5pN5zsLq9hay4bA0npqLsZojvrUSkUNAxLtqLhNmle3ORTw4XnbrjNBeYBJk0C qM0RFZCodnxU1GCo4q6vazFBScmyiNIMUDKEC7KijculYg3imJMMxBh7RPWOMY1yrL32 vC6A== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20210112; h=x-gm-message-state:mime-version:references:in-reply-to:from:date :message-id:subject:to:cc; bh=QoQdoesDidCN5z4K1TfE/oxDwd8GfagNFE2hl9gCHOY=; b=NJeoH29VpqeSeueqcSqIqytdi+mYulDfGfcCumtuHwE3GCthZg3ymwQBF+bIIOAqJp izkBTo1sf0A0EaYsUIUY3WAcD4JcycDTs+0N3n8R5K5WFhu9WJXHdXvM6s/8ryngxgdV u0JVBMfTlVzh6XSt9GyHujvjX8dmGrUdoqkGu6GPyuwKSWr9xYJsmIujB0yldGvAj2H1 oxfg8/rak4UrTUP8u02g8ABytBjgyR3YT3z1dCuJ4yZpUZ/OIOFg6+G3lNjaLlCBz1YJ cxG/XY/IK/BUvq1QDMUJbgKLH23mM/dTSenDaRlLAtTaEZIwQfX/equQ6dwepPdNDvsg OuRw== X-Gm-Message-State: AOAM530Y90hGc5J+FdjUAyN6WGPrrq6r06uVMQk/WWQSPeoWyLOLs20N 849olnGfC8/MdPOx7mqvIweZGaDaFSIsqKuH6ugtfA== X-Google-Smtp-Source: ABdhPJz+ScqSGCOyGak1a/45rr2pSio2pjaIRkXzqJnCCQuiDBdUAnQi+WLbTRrSaiUB1RPBEOT0S7itC0kxed0O2mI= X-Received: by 2002:a25:2d64:: with SMTP id s36mr12584693ybe.277.1641992820194; Wed, 12 Jan 2022 05:07:00 -0800 (PST) MIME-Version: 1.0 References: <20220112102805.488510-1-maximmi@nvidia.com> In-Reply-To: <20220112102805.488510-1-maximmi@nvidia.com> From: Eric Dumazet Date: Wed, 12 Jan 2022 05:06:49 -0800 Message-ID: Subject: Re: [PATCH] sch_api: Don't skip qdisc attach on ingress To: Maxim Mikityanskiy Cc: Eric Dumazet , "David S. Miller" , Jakub Kicinski , Jamal Hadi Salim , Cong Wang , Jiri Pirko , Tariq Toukan , netdev Content-Type: text/plain; charset="UTF-8" Precedence: bulk List-ID: X-Mailing-List: netdev@vger.kernel.org On Wed, Jan 12, 2022 at 2:28 AM Maxim Mikityanskiy wrote: > > The attach callback of struct Qdisc_ops is used by only a few qdiscs: > mq, mqprio and htb. qdisc_graft() contains the following logic > (pseudocode): > > if (!qdisc->ops->attach) { > if (ingress) > do ingress stuff; > else > do egress stuff; > } > if (!ingress) { > ... > if (qdisc->ops->attach) > qdisc->ops->attach(qdisc); > } else { > ... > } > > unregister_netdevice: waiting for lo to become free. Usage count = 2 > > This commit addresses the issue by running "do ingress stuff" in the > ingress flow even in the attach callback is present, which is fine, > because attach isn't going to be called afterwards. > > The bug was found by syzbot and reported by Eric. > > Fixes: d03b195b5aa0 ("sch_htb: Hierarchical QoS hardware offload") > Signed-off-by: Maxim Mikityanskiy > Reported-by: Eric Dumazet > --- Thanks for fixing this issue. Reviewed-by: Eric Dumazet