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=-4.0 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, MAILING_LIST_MULTI,SIGNED_OFF_BY,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 0BE76C43381 for ; Mon, 4 Mar 2019 18:56:29 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id DB7B6206BA for ; Mon, 4 Mar 2019 18:56:28 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1727603AbfCDS42 (ORCPT ); Mon, 4 Mar 2019 13:56:28 -0500 Received: from shards.monkeyblade.net ([23.128.96.9]:37658 "EHLO shards.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726073AbfCDS41 (ORCPT ); Mon, 4 Mar 2019 13:56:27 -0500 Received: from localhost (unknown [IPv6:2601:601:9f80:35cd::d71]) (using TLSv1 with cipher AES256-SHA (256/256 bits)) (Client did not present a certificate) (Authenticated sender: davem-davemloft) by shards.monkeyblade.net (Postfix) with ESMTPSA id 6CFA414696B8E; Mon, 4 Mar 2019 10:56:26 -0800 (PST) Date: Mon, 04 Mar 2019 10:56:26 -0800 (PST) Message-Id: <20190304.105626.1023614167952594956.davem@davemloft.net> To: idosch@mellanox.com Cc: netdev@vger.kernel.org, nikolay@cumulusnetworks.com, mlxsw@mellanox.com Subject: Re: [PATCH net] ip6mr: Do not call __IP6_INC_STATS() from preemptible context From: David Miller In-Reply-To: <20190303073330.10698-1-idosch@mellanox.com> References: <20190303073330.10698-1-idosch@mellanox.com> X-Mailer: Mew version 6.8 on Emacs 26.1 Mime-Version: 1.0 Content-Type: Text/Plain; charset=us-ascii Content-Transfer-Encoding: 7bit X-Greylist: Sender succeeded SMTP AUTH, not delayed by milter-greylist-4.5.12 (shards.monkeyblade.net [149.20.54.216]); Mon, 04 Mar 2019 10:56:26 -0800 (PST) Sender: netdev-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: netdev@vger.kernel.org From: Ido Schimmel Date: Sun, 3 Mar 2019 07:34:57 +0000 > Similar to commit 44f49dd8b5a6 ("ipmr: fix possible race resulting from > improper usage of IP_INC_STATS_BH() in preemptible context."), we cannot > assume preemption is disabled when incrementing the counter and > accessing a per-CPU variable. > > Preemption can be enabled when we add a route in process context that > corresponds to packets stored in the unresolved queue, which are then > forwarded using this route [1]. > > Fix this by using IP6_INC_STATS() which takes care of disabling > preemption on architectures where it is needed. ... > Fixes: 0912ea38de61 ("[IPV6] MROUTE: Add stats in multicast routing module method ip6_mr_forward().") > Signed-off-by: Ido Schimmel > Reported-by: Amit Cohen Applied and queued up for -stable, thanks.