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=-8.8 required=3.0 tests=BAYES_00,DKIM_SIGNED, DKIM_VALID,HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_CR_TRAILER, MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS,URIBL_BLOCKED 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 3019DC433E6 for ; Tue, 26 Jan 2021 12:46:27 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 0A40523121 for ; Tue, 26 Jan 2021 12:46:27 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S2391796AbhAZMqD (ORCPT ); Tue, 26 Jan 2021 07:46:03 -0500 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:43878 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S2391647AbhAZKDk (ORCPT ); Tue, 26 Jan 2021 05:03:40 -0500 Received: from mail-ed1-x52f.google.com (mail-ed1-x52f.google.com [IPv6:2a00:1450:4864:20::52f]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 14372C06174A for ; Tue, 26 Jan 2021 02:03:00 -0800 (PST) Received: by mail-ed1-x52f.google.com with SMTP id c2so18727568edr.11 for ; Tue, 26 Jan 2021 02:03:00 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=resnulli-us.20150623.gappssmtp.com; s=20150623; h=date:from:to:cc:subject:message-id:references:mime-version :content-disposition:in-reply-to; bh=r0PEk1uUKM5Q9q/+MGqHGgCH1yxOpiIv91u8qq+76tw=; b=Nx5rzbRRJmiojIU5lVxNWI69CKbFX2mVcLTlMH5MAJetlFeEHzpbTtVmkDUNhT06Pm o5xMpAy24oHNFS6kgdrRKDehMcNLir3XYyoeTSnY6NvjIh4/+NZGYfED1eIBEC4St8C8 SndGD3Suj+1BvWGTpjBHG+IY9TtzTrJAvAeCjErfYhDExG2iVX6sP7gqpNVxiOBEKZI2 zi11aLgNSYep2Qz8v9wNrn8X6gqc0bMLDds38yzuJPrHBZYZ3Q94rA2+sVRHWOamIiWh QHp2+HZku5KfsOu5osLckvKXPnitWVLE02vzXWJb9jtxwT71FIOxcTHGUhaUr+KvE5Cm VyiQ== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:date:from:to:cc:subject:message-id:references :mime-version:content-disposition:in-reply-to; bh=r0PEk1uUKM5Q9q/+MGqHGgCH1yxOpiIv91u8qq+76tw=; b=PD3R9W8GpTVgB/lLE2jr+hHe/MtOOr90OQPVGJxQ8r9QKNe9GsSXzz2gSRI2QYt6wG 6W+wWA48c9N90XsfDvTFgW9RzrDb68YxRpI+bnRshcpztzUAFOevHafThBkSKM34a2by NaNqeT3t8A2YN8DEGBE5t9a9t4A3PsDLADAV2VRBnEwNMMlFTRP+9G/NAuyZsteTa4LS E4zdBuuCgX9scaLKQ74qUaas9kbu1WZcMltND/1pFyOx7AeVDKyVXsHD1M+A1TBrTmAI SRzeWDyuLyMOfJRDqw+AaGbJbXQW1TXyTRe7M/owKsJ3KpOv83UFHZRrslhVJGRILZNh QcUA== X-Gm-Message-State: AOAM533nbNivNN6+jJ0wVDP5Y+GQgd0U2AgP99hei/JOldfA1SqaqQmB 0yLBtf8vUXZ4Xn5Ak+QOyj68hA== X-Google-Smtp-Source: ABdhPJwvMoBWgevYlTDP7GMOl+FiuvLn3103n++BnlpWARsldzAvMdl331aoaTpkyTm9/yF54NB+AQ== X-Received: by 2002:a05:6402:306a:: with SMTP id bs10mr3950881edb.209.1611655378812; Tue, 26 Jan 2021 02:02:58 -0800 (PST) Received: from localhost ([86.61.181.4]) by smtp.gmail.com with ESMTPSA id v25sm9596974ejw.21.2021.01.26.02.02.58 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Tue, 26 Jan 2021 02:02:58 -0800 (PST) Date: Tue, 26 Jan 2021 11:02:57 +0100 From: Jiri Pirko To: Ivan Vecera Cc: netdev@vger.kernel.org, "David S . Miller" , Cong Wang , Jakub Kicinski , Saeed Mahameed Subject: Re: [PATCH net] team: protect features update by RCU to avoid deadlock Message-ID: <20210126100257.GN3565223@nanopsycho.orion> References: <20210125074416.4056484-1-ivecera@redhat.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20210125074416.4056484-1-ivecera@redhat.com> Precedence: bulk List-ID: X-Mailing-List: netdev@vger.kernel.org Mon, Jan 25, 2021 at 08:44:16AM CET, ivecera@redhat.com wrote: >Function __team_compute_features() is protected by team->lock >mutex when it is called from team_compute_features() used when >features of an underlying device is changed. This causes >a deadlock when NETDEV_FEAT_CHANGE notifier for underlying device >is fired due to change propagated from team driver (e.g. MTU >change). It's because callbacks like team_change_mtu() or >team_vlan_rx_{add,del}_vid() protect their port list traversal >by team->lock mutex. > >Example (r8169 case where this driver disables TSO for certain MTU >values): >... >[ 6391.348202] __mutex_lock.isra.6+0x2d0/0x4a0 >[ 6391.358602] team_device_event+0x9d/0x160 [team] >[ 6391.363756] notifier_call_chain+0x47/0x70 >[ 6391.368329] netdev_update_features+0x56/0x60 >[ 6391.373207] rtl8169_change_mtu+0x14/0x50 [r8169] >[ 6391.378457] dev_set_mtu_ext+0xe1/0x1d0 >[ 6391.387022] dev_set_mtu+0x52/0x90 >[ 6391.390820] team_change_mtu+0x64/0xf0 [team] >[ 6391.395683] dev_set_mtu_ext+0xe1/0x1d0 >[ 6391.399963] do_setlink+0x231/0xf50 >... > >In fact team_compute_features() called from team_device_event() >does not need to be protected by team->lock mutex and rcu_read_lock() >is sufficient there for port list traversal. > >Fixes: 3d249d4ca7d0 ("net: introduce ethernet teaming device") >Cc: Jiri Pirko >Cc: David S. Miller >Cc: Cong Wang >Cc: Jakub Kicinski >Cc: Saeed Mahameed >Signed-off-by: Ivan Vecera Reviewed-by: Jiri Pirko