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=-1.1 required=3.0 tests=DKIM_SIGNED,DKIM_VALID, DKIM_VALID_AU,FREEMAIL_FORGED_FROMDOMAIN,FREEMAIL_FROM, HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI,SPF_HELO_NONE,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 97E75C282CE for ; Wed, 5 Jun 2019 02:06:04 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 572B32070B for ; Wed, 5 Jun 2019 02:06:04 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (2048-bit key) header.d=gmail.com header.i=@gmail.com header.b="Oy1Lew1b" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1726510AbfFECGD (ORCPT ); Tue, 4 Jun 2019 22:06:03 -0400 Received: from mail-pl1-f193.google.com ([209.85.214.193]:44680 "EHLO mail-pl1-f193.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726293AbfFECGC (ORCPT ); Tue, 4 Jun 2019 22:06:02 -0400 Received: by mail-pl1-f193.google.com with SMTP id c5so9080709pll.11 for ; Tue, 04 Jun 2019 19:06:02 -0700 (PDT) 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=m+rRMCjHR6VZHbkoJXjJIdErttpII88SWS9j+suw/xE=; b=Oy1Lew1b8vz4WxkjYnYSeqbhMRM/MIrMVNb/HiUEgiL7FNZkZHbSVJ6bHMVHxFOop9 +WSQeyMFHkCTXE0hzyGfiEFhNH9W3co5nqa35yX3aGi1wrmU8lwYzpj9sexOArLcchxG fZ+WdtmQB1mFnftRyevGCuWxexwYExe4/1iYQME/8HkZ8FbTlEyIsQDWd8Kos6z+9jcD v1+GGa1rovW32EM2VHCvzD8rHgW81n0RROAniE/76gdStcSDxUQnr6t5ZxCisLuWuCyf HK7gsOfLjz5d6oyhXh3t1YRSihIUGynMn0WBFeMtpu/oobJUXXMwzpHyG/PAheiyJ2Lc FOWQ== 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=m+rRMCjHR6VZHbkoJXjJIdErttpII88SWS9j+suw/xE=; b=OImbAyumvbm3ZxoclDgiIg3XmN45CXmSlvgAXAqEI2uj/+29EGe5mB0SvLsP4qT6/U Gz2OH7UqStcmisIpEDfE8/7I8dYDjCWsxQUpHpCOchG8lk6cOzzwfipkt7ZrXZUfRxEI VfhkcZYGmPP+X1gIZaX9JVezIEIdNM4UYFxtWpUNBCNuQ05jg43HqOVcKH+9m10zaKub bCzdJndwH4hGZK6KUnaUwVToAgwYPHk6R1lR2jUVKlS+g9bc9iXKZCC8RcCUcrms+aDK 1vGY1LvstUX4Vtmy1OpDO6NXe5E9Cjbtf9c3cJRpE8FlzoplSMHrLdEyF5KeQZHJlB0d yFKQ== X-Gm-Message-State: APjAAAWDUm9MZgFLh2Uda5E+ZhaxNa6MaPkOdm8lhL59iOGMbajZj2Cn IrH44R1AqdjAn5nUQv0QW3U= X-Google-Smtp-Source: APXvYqw74Cp9wOetU/7TLy8+OjvGSrmMGghsEmSC7yRZRxUytkUzYFG8fhmCUmKZbJ3kW0PCg/GzWQ== X-Received: by 2002:a17:902:6bc8:: with SMTP id m8mr39216503plt.227.1559700362013; Tue, 04 Jun 2019 19:06:02 -0700 (PDT) Received: from [172.27.227.186] ([216.129.126.118]) by smtp.googlemail.com with ESMTPSA id x128sm22173486pfd.186.2019.06.04.19.05.59 (version=TLS1_2 cipher=ECDHE-RSA-AES128-GCM-SHA256 bits=128/128); Tue, 04 Jun 2019 19:06:00 -0700 (PDT) Subject: Re: [PATCH v2 net-next 4/7] ipv6: Plumb support for nexthop object in a fib6_info To: Martin Lau , Wei Wang Cc: David Ahern , "David S . Miller" , Linux Kernel Network Developers , "idosch@mellanox.com" , "saeedm@mellanox.com" References: <5263d3ae-1865-d935-cb03-f6dfd4604d15@gmail.com> <4cdcdf65-4d34-603e-cb21-d649b399d760@gmail.com> <20190604005840.tiful44xo34lpf6d@kafai-mbp.dhcp.thefacebook.com> <453565b0-d08a-be96-3cd7-5608d4c21541@gmail.com> <20190604052929.4mlxa5sswm46mwrq@kafai-mbp.dhcp.thefacebook.com> <20190604210619.kq5jnkinak7izn2u@kafai-mbp.dhcp.thefacebook.com> <0c307c47-4cde-1e55-8168-356b2ef30298@gmail.com> <20190605003903.zxxrebpzq2rfzy52@kafai-mbp.dhcp.thefacebook.com> From: David Ahern Message-ID: Date: Tue, 4 Jun 2019 20:05:58 -0600 User-Agent: Mozilla/5.0 (Macintosh; Intel Mac OS X 10.14; rv:52.0) Gecko/20100101 Thunderbird/52.9.1 MIME-Version: 1.0 In-Reply-To: <20190605003903.zxxrebpzq2rfzy52@kafai-mbp.dhcp.thefacebook.com> Content-Type: text/plain; charset=utf-8 Content-Language: en-US Content-Transfer-Encoding: 7bit Sender: netdev-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: netdev@vger.kernel.org On 6/4/19 6:39 PM, Martin Lau wrote: > IMO, ip6_create_rt_rcu(), which returns untracked rt, was a mistake > and removing it has been overdue. Tracking down the unregister dev > bug is not easy. I must be missing something because I don't have the foggiest idea why you are barking up this tree. If code calls a function that returns a dst_entry with a refcount taken, that code is responsible for releasing it. Using a pcpu cached dst versus a new one in no way tells you who took the dst and bumped the refcnt on the netdev. Either way the dst refcount is bumped. Tracking netdev refcnt is the only way to methodically figure it out. What am I overlooking here?