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 mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 945CCC433EF for ; Thu, 30 Sep 2021 00:29:46 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 6CA47613D1 for ; Thu, 30 Sep 2021 00:29:46 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1347101AbhI3Ab1 (ORCPT ); Wed, 29 Sep 2021 20:31:27 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:40934 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S233113AbhI3Ab0 (ORCPT ); Wed, 29 Sep 2021 20:31:26 -0400 Received: from mail-pj1-x1029.google.com (mail-pj1-x1029.google.com [IPv6:2607:f8b0:4864:20::1029]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id C3005C06161C for ; Wed, 29 Sep 2021 17:29:44 -0700 (PDT) Received: by mail-pj1-x1029.google.com with SMTP id ce20-20020a17090aff1400b0019f13f6a749so5161963pjb.4 for ; Wed, 29 Sep 2021 17:29:44 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20210112; h=subject:to:references:from:message-id:date:user-agent:mime-version :in-reply-to:content-language:content-transfer-encoding; bh=qwjNHpJA6FY0nu6BFzuBNE38cf2EdeXQAYK4wdXPBJs=; b=f10uZRFrvZ6uVMjSpkWkpj7DBdnSuAigwsnqg1iCtHnkwpc9BGiyIPzZ32oewOYLZX ZcImu1VZKUV258YI0Lu6X2NpgDAS8tX5jPtT2ho1Z4xIwCNtT1mif3kjLW+z7WCIRmSA vzfo3jWnUgg+MCjiO51ak5xZAnGZtneLqg5FESH56+waSonQ3gfUI3duwjibht4bhbW5 bS3926SGJ2Pn+sHmj+ML3YKh4QBoBOlz0eibb8PxzsBBBUUWHF/dbx84MC7On0khLwMX vdyHNiSul0pErMWp/TOO1E4j0d2APXz/hgTjsGPPLUmaMZJ9uuHfVLsCMT2jtFztKpvq M74g== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20210112; h=x-gm-message-state:subject:to:references:from:message-id:date :user-agent:mime-version:in-reply-to:content-language :content-transfer-encoding; bh=qwjNHpJA6FY0nu6BFzuBNE38cf2EdeXQAYK4wdXPBJs=; b=jFbI1TvR5rqE0tdAy1d9QEGfAHNQXeCmIPuulR3eQwz7thzwBDwbmDjY0cJyFI79xf UUDTM5OVr9dF1qXqeCqVbCApdbeXyXGKSk6HBE2OYi/lVQ7lDwGhL/bU9jLXId81gdL6 RSxkhFAxwLogfjXVvEGUijhbbkZb6Vu6D/O4yPeL6Vd9u+4HAeo+J2m/wxmQzJJ1gYmT 0v9gE7PmV5n24cCC2du5uyquk4e8+9Vldzg4GzT2VZAOJRXoyLBX51jqvzHsBdsqBXw4 YTBG9gD96xcyHWyeiU/HMyV5204JCxX+VDTwsPwGP6NCrPh69510B78N/jFcQM9NPaKi fAdw== X-Gm-Message-State: AOAM532+uu/Sf5qw+Na3OHZRnwyVLWCOC2UvXsxmS4/pJ67SbiWfE953 4o0lihoentzUqjDVJe7huytjNZCZRqQ= X-Google-Smtp-Source: ABdhPJy5Ic/h6aPp7oK1c6vW5wgfJ/5nvt51DIUv5gqPonPPjrQeP0ZMJmI0pcTiBp46zSobzF8p8A== X-Received: by 2002:a17:902:6e02:b0:13a:41f5:1666 with SMTP id u2-20020a1709026e0200b0013a41f51666mr2593007plk.39.1632961784104; Wed, 29 Sep 2021 17:29:44 -0700 (PDT) Received: from [192.168.86.235] (c-73-241-150-58.hsd1.ca.comcast.net. [73.241.150.58]) by smtp.gmail.com with ESMTPSA id f4sm707551pgn.93.2021.09.29.17.29.42 (version=TLS1_3 cipher=TLS_AES_128_GCM_SHA256 bits=128/128); Wed, 29 Sep 2021 17:29:43 -0700 (PDT) Subject: Re: 5.15-rc3+ crash in fq-codel? To: Ben Greear , Eric Dumazet , netdev References: <00e495ba-391e-6ad8-94a2-930fbc826a37@candelatech.com> <296232ac-e7ed-6e3c-36b9-ed430a21f632@candelatech.com> <7e87883e-42f5-2341-ab67-9f1614fb8b86@candelatech.com> <7f1d67f1-3a2c-2e74-bb86-c02a56370526@gmail.com> <88bc8a03-da44-fc15-f032-fe5cb592958b@candelatech.com> <41b4221b-be68-da96-8cbf-4297bb7ba821@gmail.com> <8768df9e-f1f6-db25-15d8-cabed2346f32@candelatech.com> From: Eric Dumazet Message-ID: Date: Wed, 29 Sep 2021 17:29:42 -0700 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:78.0) Gecko/20100101 Thunderbird/78.14.0 MIME-Version: 1.0 In-Reply-To: Content-Type: text/plain; charset=utf-8 Content-Language: en-US Content-Transfer-Encoding: 8bit Precedence: bulk List-ID: X-Mailing-List: netdev@vger.kernel.org On 9/29/21 5:04 PM, Ben Greear wrote: > On 9/29/21 4:48 PM, Ben Greear wrote: >> On 9/29/21 4:42 PM, Eric Dumazet wrote: >>> >>> >>> On 9/29/21 4:28 PM, Eric Dumazet wrote: >>>> >>> >>>> >>>> Actually the bug seems to be in pktgen, vs NET_XMIT_CN >>>> >>>> You probably would hit the same issues with other qdisc also using NET_XMIT_CN >>>> >>> >>> I would try the following patch : >>> >>> diff --git a/net/core/pktgen.c b/net/core/pktgen.c >>> index a3d74e2704c42e3bec1aa502b911c1b952a56cf1..0a2d9534f8d08d1da5dfc68c631f3a07f95c6f77 100644 >>> --- a/net/core/pktgen.c >>> +++ b/net/core/pktgen.c >>> @@ -3567,6 +3567,7 @@ static void pktgen_xmit(struct pktgen_dev *pkt_dev) >>>          case NET_XMIT_DROP: >>>          case NET_XMIT_CN: >>>                  /* skb has been consumed */ >>> +               pkt_dev->last_ok = 1; >>>                  pkt_dev->errors++; >>>                  break; >>>          default: /* Drivers are not supposed to return other values! */ > > While patching my variant of pktgen, I took a look at the 'default' case.  I think > it should probably go above NET_XMIT_DROP and fallthrough into the consumed pkt path? > > Although, probably not a big deal since only bugs elsewhere would hit that path, and > we don't really know if skb would be consumed in that case or not. > This is probably dead code after commit commit f466dba1832f05006cf6caa9be41fb98d11cb848 pktgen: ndo_start_xmit can return NET_XMIT_xxx values So this does not really matter anymore.