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=-5.5 required=3.0 tests=DKIMWL_WL_MED,DKIM_SIGNED, DKIM_VALID,HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI,SIGNED_OFF_BY, SPF_PASS,URIBL_BLOCKED,USER_AGENT_MUTT 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 38346C282D7 for ; Tue, 5 Feb 2019 09:51:52 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 067832073D for ; Tue, 5 Feb 2019 09:51:52 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (2048-bit key) header.d=resnulli-us.20150623.gappssmtp.com header.i=@resnulli-us.20150623.gappssmtp.com header.b="RS+Z3KNh" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1727842AbfBEJvu (ORCPT ); Tue, 5 Feb 2019 04:51:50 -0500 Received: from mail-wr1-f42.google.com ([209.85.221.42]:37017 "EHLO mail-wr1-f42.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726484AbfBEJvt (ORCPT ); Tue, 5 Feb 2019 04:51:49 -0500 Received: by mail-wr1-f42.google.com with SMTP id s12so2877668wrt.4 for ; Tue, 05 Feb 2019 01:51:48 -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:user-agent; bh=mBCZM2PGzD4c/iBWn+/THGP8aaQy1TJqd/jO2yQujBA=; b=RS+Z3KNhl7dyMp9u4f5Bs04Lt1sFspo42zR/R3JfFwPIfQ3ckqc/wTFdytBD5Jw5qa HNdygU6Xu+5SJUAPmV7Bj25eGv1APOqIY0DlLRYOwgaku47wFjARKWoZLbdT/CDetDDX 4JYqWs/9zFYEzD3Sb7OtZv1Vu9ZDbSLVOzi/fZrSqPSveOdhOxcOKwsui2y+Ey5Co/a4 B5wFxHtmLs1Y3oiXyTS3XXxKtvp+xF3u+a5b5pKgp5e7FoaxXWCnSFZPdkxJjLbTiUFg TDVR+kCVPGa0L0uex0RWnBhQz/3zGDuE7qcELnVh4S/dv3A9OLufQC1I2eOC0FdNKILa rgOA== 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:user-agent; bh=mBCZM2PGzD4c/iBWn+/THGP8aaQy1TJqd/jO2yQujBA=; b=dgJ11Igl+H9fg7dA9M5odWbNuy3/gRSeJMFTBcw/ACS6o467ENnjX2jM7rW8uJg7uh ywV2ft3escQojoj2JL5VxwwPiBTVsjtk5NbRY41hXleTkzj4rlPQsBxaO64sf30hRg9e VkRr2rRj57NBoCgh9Fu6UqzlN0zBIK44QkqLYfMLPNbbSMXl6bUhthEeKOp0jtFZl8E0 5N9QakHXUogDPuSWnbrQfDl1C/Ib6bVbowBt5UpqqO0Z+65v83Tne2NqEEMHmsFvZRcB VDxOJA0eNL6Z3jCUmeNnxF2GgYuWybO/EC+pJ5tRgA64mEPXZkXwDrszTVQZj+VeCwY6 Fa9A== X-Gm-Message-State: AHQUAuYLZc02x4p/7+HGdiXaxsPgeNu5H5uJq4xaIsJP5jMAtkUChaW0 0pgta5PHW7KyWLpGem62Qj4syQ== X-Google-Smtp-Source: AHgI3IYr1PSqzgIcBQc7u1ZJ97EtHyse09CO3GZx3qnjnSd/wuaVBb+khhry72p3vq/OAfWV1nVrMA== X-Received: by 2002:adf:e64d:: with SMTP id b13mr2991734wrn.276.1549360308172; Tue, 05 Feb 2019 01:51:48 -0800 (PST) Received: from localhost (mail.chocen-mesto.cz. [85.163.43.2]) by smtp.gmail.com with ESMTPSA id c7sm2985185wrn.71.2019.02.05.01.51.47 (version=TLS1_2 cipher=ECDHE-RSA-CHACHA20-POLY1305 bits=256/256); Tue, 05 Feb 2019 01:51:47 -0800 (PST) Date: Tue, 5 Feb 2019 10:42:38 +0100 From: Jiri Pirko To: Vlad Buslov Cc: netdev@vger.kernel.org, jhs@mojatatu.com, xiyou.wangcong@gmail.com, davem@davemloft.net, ast@kernel.org, daniel@iogearbox.net Subject: Re: [PATCH net-next v3 05/16] net: sched: protect chain template accesses with block lock Message-ID: <20190205094238.GB2133@nanopsycho> References: <20190204123301.4223-1-vladbu@mellanox.com> <20190204123301.4223-6-vladbu@mellanox.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20190204123301.4223-6-vladbu@mellanox.com> User-Agent: Mutt/1.10.1 (2018-07-13) Sender: netdev-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: netdev@vger.kernel.org Mon, Feb 04, 2019 at 01:32:50PM CET, vladbu@mellanox.com wrote: >When cls API is called without protection of rtnl lock, parallel >modification of chain is possible, which means that chain template can be >changed concurrently in certain circumstances. For example, when chain is >'deleted' by new user-space chain API, the chain might continue to be used >if it is referenced by actions, and can be 're-created' again by user. In >such case same chain structure is reused and its template is changed. To >protect from described scenario, cache chain template while holding block >lock. Introduce standalone tc_chain_notify_delete() function that works >with cached template values, instead of chains themselves. > >Signed-off-by: Vlad Buslov Acked-by: Jiri Pirko