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=-14.2 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,INCLUDES_PATCH, MAILING_LIST_MULTI,NICE_REPLY_A,SPF_HELO_NONE,SPF_PASS,URIBL_BLOCKED, 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 94D01C433E0 for ; Wed, 10 Mar 2021 16:15:47 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 693B964F4A for ; Wed, 10 Mar 2021 16:15:47 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S233087AbhCJQPR (ORCPT ); Wed, 10 Mar 2021 11:15:17 -0500 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:54760 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S231519AbhCJQPJ (ORCPT ); Wed, 10 Mar 2021 11:15:09 -0500 Received: from mail-ot1-x334.google.com (mail-ot1-x334.google.com [IPv6:2607:f8b0:4864:20::334]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 37EF8C061760 for ; Wed, 10 Mar 2021 08:15:09 -0800 (PST) Received: by mail-ot1-x334.google.com with SMTP id n23so11269006otq.1 for ; Wed, 10 Mar 2021 08:15:09 -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=T7kGzRNnCMOsh/8T66jkf8hStIE3TfkmsNmveWUDPuw=; b=WhZFLjlCPlWj1jdggSsadPWwEPhsY/kGXjZgXJUjYcUdad/SpAo0myr5fLHzBQb2S0 ipGqvPqJs2LNtzQhj4qswq0+/zN9JAYs6ViHJoujr/2VyaadtzdFXPL4PJPKtry/v14d uLjC7nmJEYiIu9imgYPS/+Y+10oBWzo5OQhATxdKxx5q1haphwxc5tqFrZkQxru2l0qk CvQ8dGiTXqrA6B+Z+3URcUdQjA35LUfR0B1n+t3aZM4BYiDmCpAsv4fYuTS+cNqUaZ0W MWEomEq+ZgUbzF/GkHaB6HQtOWysjNgWMbinkN/A36CCE6lLcYE3J3G1XD3ySsLL41IJ xwqw== 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=T7kGzRNnCMOsh/8T66jkf8hStIE3TfkmsNmveWUDPuw=; b=OKFxWw36l0a4nNToniCFUAQWHwHl+VQmtCOH5lTCkiRD0LYxb0GU2M7i1Ob9Qhc6uQ 1O+AXhZ5GYS7EIu7I7TlY4JRYDkitbr1xsB/WRXoTKav6jOw/CSgKH/wL+E5NRQaxtYJ ccc6IPiLCOyaxYm7b+apOmTi2JeSppnPiDR7Upvr7NXirsDApjusQ/wE5Ha5pWcwFSjf DjFhQFnFZ+zohbzL+5+2WZzmMlOIRlThYsCDQ4p9uHuqzOvGZicCutiThlPag+lDDv91 TXLbbS5BjqjzNhp5RSvnxNkJWnKeS6LDVlIwPatb50a22EuJFFZUeLfFT4sPxnKaW+pO uvBA== X-Gm-Message-State: AOAM533/q6h4my+GdQs4OdxuVhNvUKa8FGIfBKgMe/Xhtfxbhcq0Xs+q q/fF8c20gwy4ZQMfjnklaxI= X-Google-Smtp-Source: ABdhPJz3wK5lEPXskOjxvfF95xz7hR/CDeIdgS8oNvtqXIMDLRpohWhsorjh4VXWOudnq1fpy8MAJA== X-Received: by 2002:a9d:19a3:: with SMTP id k32mr3157266otk.189.1615392908695; Wed, 10 Mar 2021 08:15:08 -0800 (PST) Received: from Davids-MacBook-Pro.local ([8.48.134.56]) by smtp.googlemail.com with ESMTPSA id s21sm3719414oos.5.2021.03.10.08.15.06 (version=TLS1_3 cipher=TLS_AES_128_GCM_SHA256 bits=128/128); Wed, 10 Mar 2021 08:15:07 -0800 (PST) Subject: Re: [PATCH net v2] ipv6: fix suspecious RCU usage warning To: Wei Wang , "David S . Miller" , Jakub Kicinski , netdev@vger.kernel.org Cc: syzbot , David Ahern , Ido Schimmel , Petr Machata , Eric Dumazet References: <20210310022035.2908294-1-weiwan@google.com> From: David Ahern Message-ID: <2cdaaaed-7529-48cf-5bcc-59da5c93c6d2@gmail.com> Date: Wed, 10 Mar 2021 09:15:03 -0700 User-Agent: Mozilla/5.0 (Macintosh; Intel Mac OS X 10.16; rv:78.0) Gecko/20100101 Thunderbird/78.8.0 MIME-Version: 1.0 In-Reply-To: <20210310022035.2908294-1-weiwan@google.com> Content-Type: text/plain; charset=utf-8 Content-Language: en-US Content-Transfer-Encoding: 7bit Precedence: bulk List-ID: X-Mailing-List: netdev@vger.kernel.org On 3/9/21 7:20 PM, Wei Wang wrote: > Syzbot reported the suspecious RCU usage in nexthop_fib6_nh() when > called from ipv6_route_seq_show(). The reason is ipv6_route_seq_start() > calls rcu_read_lock_bh(), while nexthop_fib6_nh() calls > rcu_dereference_rtnl(). > The fix proposed is to add a variant of nexthop_fib6_nh() to use > rcu_dereference_bh_rtnl() for ipv6_route_seq_show(). > ... > > Fixes: f88d8ea67fbdb ("ipv6: Plumb support for nexthop object in a fib6_info") > Reported-by: syzbot > Signed-off-by: Wei Wang > Cc: David Ahern > Cc: Ido Schimmel > Cc: Petr Machata > Cc: Eric Dumazet > --- > include/net/nexthop.h | 24 ++++++++++++++++++++++++ > net/ipv6/ip6_fib.c | 2 +- > 2 files changed, 25 insertions(+), 1 deletion(-) > Reviewed-by: David Ahern Thanks, Wei.