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=-9.2 required=3.0 tests=BAYES_00,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,FREEMAIL_FORGED_FROMDOMAIN,FREEMAIL_FROM, HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_CR_TRAILER,MAILING_LIST_MULTI, NICE_REPLY_A,SPF_HELO_NONE,SPF_PASS,USER_AGENT_SANE_1 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 16EEDC433E0 for ; Tue, 23 Feb 2021 08:29:25 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id B667164E05 for ; Tue, 23 Feb 2021 08:29:24 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S232191AbhBWI3V (ORCPT ); Tue, 23 Feb 2021 03:29:21 -0500 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:36646 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S232182AbhBWI3U (ORCPT ); Tue, 23 Feb 2021 03:29:20 -0500 Received: from mail-ed1-x536.google.com (mail-ed1-x536.google.com [IPv6:2a00:1450:4864:20::536]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 23270C061574 for ; Tue, 23 Feb 2021 00:28:40 -0800 (PST) Received: by mail-ed1-x536.google.com with SMTP id n1so24932668edv.2 for ; Tue, 23 Feb 2021 00:28:40 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20161025; h=subject:to:cc:references:from:message-id:date:user-agent :mime-version:in-reply-to:content-language:content-transfer-encoding; bh=3Li9C7SDrwk5rNm7kTQovNBC2vU5jZhQZLg2eIYo6jM=; b=ZNnU6QLgunWOxdE81J4XYmT2qrAFVUvYjsZk0TLrupPbGFM0Ag/cNvZe8W/O5+kZ+N 49Xs7u0A3i6BHsAzdBku/sDGMJx6RgolJJ6fntXvQuCSubEdqvohdRJWA5OPLwkVFF1i EQxz4sgXZMYr7FZ1d9i4OVTSM4NOf6CZXbBp47UqcLRP2Da/YvjfoeFLbb0YTQEjlg3n khSyEhFb87bQ659lv5w76Apc3DtfIjBLZC2O6HHg3UL3lDC24+MedGfYSJzbZLkIuhp0 lfxwNnBduPSDH5/ABQ6jnLXWirTuqseILFb65Mar24jVJ+4usvChvQ4Mt/FV1TMu1A9m oB2A== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:subject:to:cc:references:from:message-id:date :user-agent:mime-version:in-reply-to:content-language :content-transfer-encoding; bh=3Li9C7SDrwk5rNm7kTQovNBC2vU5jZhQZLg2eIYo6jM=; b=Zn1R4MYigZojBzsnrUQDjXLwOjQ/s7L82fZF7KWnH92Evlzs7iEbnBwZLKhEm+lcI5 R/rKAZJkPL2c+EiUwLZK9gXZEHUNUUrebYEyessp1Uk8rCuWeESUF86W+sGcyp/ZYK6k QfNF1dXYvfJYGSFttYX9jnkklpIbn5YLLCzDu/HcwSqvfTC6/BOBGfLVEityWVinn7L+ qd9e/bzYAK8HwfZRkEGgn2UTvfoi04KwN0HUA9HndqTvg4mYBkZacVuj6OT32Yy3spL+ UG8HSa2qlbPK3Er4A3sZhvhrFfs0Iays1pbc/w7ofPXvflHdejQJGcYAVjczX2qQt9aa /NGQ== X-Gm-Message-State: AOAM5319eXKFYwTkNqSDSH8B2+awdVdP5KGtUUassSRh5phsi7vm3Pvk dt7y+BkCVueKgO1/eF+SWLU= X-Google-Smtp-Source: ABdhPJxXemTnDp6OByZ3KaE63XFS4ruEO3iOAWU6/Tfo3g05RIz7EAUoVRh31PsCQvAkpUwNZOOuZg== X-Received: by 2002:aa7:c95a:: with SMTP id h26mr26864259edt.166.1614068918827; Tue, 23 Feb 2021 00:28:38 -0800 (PST) Received: from [192.168.1.110] ([77.124.67.117]) by smtp.gmail.com with ESMTPSA id m19sm13187206eds.8.2021.02.23.00.28.37 (version=TLS1_3 cipher=TLS_AES_128_GCM_SHA256 bits=128/128); Tue, 23 Feb 2021 00:28:38 -0800 (PST) Subject: Re: [PATCH RFC net-next] mlx5: fix for crash on net-next To: Jesper Dangaard Brouer , netdev@vger.kernel.org, Saeed Mahameed Cc: Jakub Kicinski , "David S. Miller" , saeedm@nvidia.com, Tariq Toukan , eranbe@nvidia.com, maximmi@mellanox.com, Tariq Toukan , Saeed Mahameed References: <161402344429.1980160.4798557236979159924.stgit@firesoul> From: Tariq Toukan Message-ID: Date: Tue, 23 Feb 2021 10:28:35 +0200 User-Agent: Mozilla/5.0 (Windows NT 10.0; Win64; x64; rv:78.0) Gecko/20100101 Thunderbird/78.7.1 MIME-Version: 1.0 In-Reply-To: <161402344429.1980160.4798557236979159924.stgit@firesoul> Content-Type: text/plain; charset=utf-8; format=flowed Content-Language: en-US Content-Transfer-Encoding: 7bit Precedence: bulk List-ID: X-Mailing-List: netdev@vger.kernel.org On 2/22/2021 9:50 PM, Jesper Dangaard Brouer wrote: > Net-next at commit d310ec03a34e ("Merge tag 'perf-core-2021-02-17') > > There is a divide error in drivers/net/ethernet/mellanox/mlx5/core/en_tx.c > where it seems that num_tc_x_num_ch can become zero in a modulo operation: > > if (unlikely(txq_ix >= num_tc_x_num_ch)) > txq_ix %= num_tc_x_num_ch; > > I think error were introduced in: > - 214baf22870c ("net/mlx5e: Support HTB offload") > > The modulo operation was introduced in: > - 145e5637d941 ("net/mlx5e: Add TX PTP port object support") > > The crash looks like this: > > [ 12.112849] divide error: 0000 [#1] PREEMPT SMP PTI > [ 12.117727] CPU: 4 PID: 0 Comm: swapper/4 Not tainted 5.11.0-net-next+ #575 > [ 12.124677] Hardware name: Supermicro Super Server/X10SRi-F, BIOS 2.0a 08/01/2016 > [ 12.132149] RIP: 0010:mlx5e_select_queue+0xd5/0x1e0 [mlx5_core] > [ 12.138110] Code: 85 c0 75 2e 48 83 bb 08 57 00 00 00 75 5b 31 d2 48 89 ee 48 89 df e8 ba 3e 54 e1 0f b7 d0 41 39 d4 0f 8f 6b ff ff ff 89 d0 99 <41> f7 fc e9 60 ff ff ff 8b 96 8c 00 00 00 89 d1 c1 e9 10 39 c1 0f > [ 12.156849] RSP: 0018:ffffc900001c0c10 EFLAGS: 00010297 > [ 12.162065] RAX: 0000000000000004 RBX: ffff88810ff00000 RCX: 0000000000000007 > [ 12.169188] RDX: 0000000000000000 RSI: ffff888107016400 RDI: ffff8881008dc740 > [ 12.176313] RBP: ffff888107016400 R08: 0000000000000000 R09: 000000ncing: Fatal exception in interrupt ]--- > > This is an RFC, because I don't think this is a proper fix, but > at least it allows me to boot with mlx5 driver enabled. > > Signed-off-by: Jesper Dangaard Brouer > --- Hi Jesper, Thanks for your report and patch. We'll check it and post the proper fix. I wonder what's special in your configuration / use case, as I'm not aware of such failure. Can you please share more info about the reproduction? Regards, Tariq