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=-10.3 required=3.0 tests=BAYES_00, HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_CR_TRAILER,MAILING_LIST_MULTI, SPF_HELO_NONE,SPF_PASS,URIBL_RED,USER_AGENT_SANE_2 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 05CBFC433DB for ; Thu, 7 Jan 2021 20:53:41 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id C7F4E2343B for ; Thu, 7 Jan 2021 20:53:40 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1727485AbhAGUxk (ORCPT ); Thu, 7 Jan 2021 15:53:40 -0500 Received: from mail.kernel.org ([198.145.29.99]:58524 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726410AbhAGUxj (ORCPT ); Thu, 7 Jan 2021 15:53:39 -0500 Received: from gandalf.local.home (cpe-66-24-58-225.stny.res.rr.com [66.24.58.225]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPSA id 9406B2311E; Thu, 7 Jan 2021 20:52:57 +0000 (UTC) Date: Thu, 7 Jan 2021 15:52:56 -0500 From: Steven Rostedt To: Linus Torvalds Cc: Willem de Bruijn , Jakub Kicinski , David Miller , Jonathan Lemon , Thomas Gleixner , LKML , "the arch/x86 maintainers" , Christoph Hellwig , Matthew Wilcox , Daniel Vetter , Andrew Morton , Linux-MM , Peter Zijlstra , Ingo Molnar , Juri Lelli , Vincent Guittot , Dietmar Eggemann , Ben Segall , Mel Gorman , Daniel Bristot de Oliveira , Netdev Subject: Re: [BUG] from x86: Support kmap_local() forced debugging Message-ID: <20210107155256.7af2505e@gandalf.local.home> In-Reply-To: References: <20201118194838.753436396@linutronix.de> <20201118204007.169209557@linutronix.de> <20210106180132.41dc249d@gandalf.local.home> <20210106174917.3f8ad0d8@kicinski-fedora-pc1c0hjn.dhcp.thefacebook.com> X-Mailer: Claws Mail 3.17.8 (GTK+ 2.24.33; x86_64-pc-linux-gnu) MIME-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 7bit Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Thu, 7 Jan 2021 11:47:02 -0800 Linus Torvalds wrote: > On Wed, Jan 6, 2021 at 8:45 PM Willem de Bruijn wrote: > > > > But there are three other kmap_atomic callers under net/ that do not > > loop at all, so assume non-compound pages. In esp_output_head, > > esp6_output_head and skb_seq_read. The first two directly use > > skb_page_frag_refill, which can allocate compound (but not > > __GFP_HIGHMEM) pages, and the third can be inserted with > > netfilter xt_string in the path of tcp transmit skbs, which can also > > have compound pages. I think that these could similarly access > > data beyond the end of the kmap_atomic mapped page. I'll take > > a closer look. > > Thanks. > > Note that I have flushed my random one-liner patch from my system, and > expect to get a proper fix through the normal networking pulls. > > And _if_ the networking people feel that my one-liner was the proper > fix, you can use it and add my sign-off if you want to, but it really > was more of a "this is the quick ugly fix for testing" rather than > anything else. > Please add: Link: https://lore.kernel.org/linux-mm/20210106180132.41dc249d@gandalf.local.home/ Reported-by: Steven Rostedt (VMware) And if you take Linus's patch, please add my: Tested-by: Steven Rostedt (VMware) and if you come up with another patch, please send it to me for testing. Thanks! -- Steve