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=-2.5 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS,URIBL_BLOCKED,USER_AGENT_MUTT autolearn=unavailable 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 C4CB5C282E5 for ; Sat, 25 May 2019 12:12:43 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id A6A882075E for ; Sat, 25 May 2019 12:12:43 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1726885AbfEYMMm (ORCPT ); Sat, 25 May 2019 08:12:42 -0400 Received: from atrey.karlin.mff.cuni.cz ([195.113.26.193]:42733 "EHLO atrey.karlin.mff.cuni.cz" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726585AbfEYMMm (ORCPT ); Sat, 25 May 2019 08:12:42 -0400 Received: by atrey.karlin.mff.cuni.cz (Postfix, from userid 512) id 52BEA80364; Sat, 25 May 2019 14:12:30 +0200 (CEST) Date: Sat, 25 May 2019 14:11:59 +0200 From: Pavel Machek To: Greg Kroah-Hartman Cc: linux-kernel@vger.kernel.org, stable@vger.kernel.org, Pieter Jansen van Vuuren , Jakub Kicinski , John Hurley , "David S. Miller" Subject: Re: [PATCH 4.19 008/114] nfp: flower: add rcu locks when accessing netdev for tunnels Message-ID: <20190525121159.GA1376@xo-6d-61-c0.localdomain> References: <20190523181731.372074275@linuxfoundation.org> <20190523181732.329357922@linuxfoundation.org> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20190523181732.329357922@linuxfoundation.org> User-Agent: Mutt/1.5.21 (2010-09-15) Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Hi! > From: Pieter Jansen van Vuuren > > [ Upstream commit cb07d915bf278a7a3938b983bbcb4921366b5eff ] > > Add rcu locks when accessing netdev when processing route request > and tunnel keep alive messages received from hardware. > /* Get the neighbour entry for the lookup */ > n = dst_neigh_lookup(&rt->dst, &flow.daddr); > ip_rt_put(rt); > if (!n) > - goto route_fail_warning; > - nfp_tun_write_neigh(n->dev, app, &flow, n, GFP_KERNEL); > + goto fail_rcu_unlock; > + nfp_tun_write_neigh(n->dev, app, &flow, n, GFP_ATOMIC); > neigh_release(n); > + rcu_read_unlock(); > return; This will make allocations more likely to fail. I thought it is okay to sleep in rcu lock critical sections...? -- (english) http://www.livejournal.com/~pavelmachek (cesky, pictures) http://atrey.karlin.mff.cuni.cz/~pavel/picture/horses/blog.html