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=-5.3 required=3.0 tests=DKIM_SIGNED,DKIM_VALID, DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI,SIGNED_OFF_BY, SPF_HELO_NONE,SPF_PASS,URIBL_BLOCKED,USER_AGENT_SANE_1 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 4F0A7C3A59B for ; Sat, 17 Aug 2019 08:09:50 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 1DE202077C for ; Sat, 17 Aug 2019 08:09:50 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (1024-bit key) header.d=c-s.fr header.i=@c-s.fr header.b="PFmZ3tEw" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1726067AbfHQIJt (ORCPT ); Sat, 17 Aug 2019 04:09:49 -0400 Received: from pegase1.c-s.fr ([93.17.236.30]:64712 "EHLO pegase1.c-s.fr" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1725784AbfHQIJt (ORCPT ); Sat, 17 Aug 2019 04:09:49 -0400 Received: from localhost (mailhub1-int [192.168.12.234]) by localhost (Postfix) with ESMTP id 469Xsk4XFmz9typx; Sat, 17 Aug 2019 10:09:46 +0200 (CEST) Authentication-Results: localhost; dkim=pass reason="1024-bit key; insecure key" header.d=c-s.fr header.i=@c-s.fr header.b=PFmZ3tEw; dkim-adsp=pass; dkim-atps=neutral X-Virus-Scanned: Debian amavisd-new at c-s.fr Received: from pegase1.c-s.fr ([192.168.12.234]) by localhost (pegase1.c-s.fr [192.168.12.234]) (amavisd-new, port 10024) with ESMTP id sNvX-0_3f_4K; Sat, 17 Aug 2019 10:09:46 +0200 (CEST) Received: from messagerie.si.c-s.fr (messagerie.si.c-s.fr [192.168.25.192]) by pegase1.c-s.fr (Postfix) with ESMTP id 469Xsk3PNRz9typs; Sat, 17 Aug 2019 10:09:46 +0200 (CEST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=c-s.fr; s=mail; t=1566029386; bh=pVI9gY6iiTOKFqgekWFv504Tf/QYksOUjRjQFOu2kD0=; h=Subject:To:References:From:Date:In-Reply-To:From; b=PFmZ3tEwbCcnorGnd5QrmBxwxFFSuDEhTO5ZjS4uBLNisb+UKUNsl94HoIWJQIWXF bOBEfuKIST6lerMbAPKSPdZzybS4qFVQ/HaIuSoZO3dGUCBsiLoMn8RJkAXWz528uW yVq0TMp+3G9mqWqk98b8zsX+IrJ6HBJWVGviJp44= Received: from localhost (localhost [127.0.0.1]) by messagerie.si.c-s.fr (Postfix) with ESMTP id 9214B8B793; Sat, 17 Aug 2019 10:09:47 +0200 (CEST) X-Virus-Scanned: amavisd-new at c-s.fr Received: from messagerie.si.c-s.fr ([127.0.0.1]) by localhost (messagerie.si.c-s.fr [127.0.0.1]) (amavisd-new, port 10023) with ESMTP id Lp6brMJxdad5; Sat, 17 Aug 2019 10:09:47 +0200 (CEST) Received: from [192.168.232.53] (unknown [192.168.232.53]) by messagerie.si.c-s.fr (Postfix) with ESMTP id EAA278B790; Sat, 17 Aug 2019 10:09:46 +0200 (CEST) Subject: Re: [Bug 204371] BUG kmalloc-4k (Tainted: G W ): Object padding overwritten To: bugzilla-daemon@bugzilla.kernel.org, linuxppc-dev@lists.ozlabs.org, Andrew Morton , Linux Memory Management List , linux-btrfs@vger.kernel.org, erhard_f@mailbox.org, Chris Mason , Josef Bacik , David Sterba , Michael Ellerman References: From: christophe leroy Message-ID: Date: Sat, 17 Aug 2019 10:09:46 +0200 User-Agent: Mozilla/5.0 (Windows NT 6.1; WOW64; rv:60.0) Gecko/20100101 Thunderbird/60.8.0 MIME-Version: 1.0 In-Reply-To: Content-Type: text/plain; charset=utf-8; format=flowed Content-Language: fr Content-Transfer-Encoding: 8bit X-Antivirus: Avast (VPS 190816-4, 16/08/2019), Outbound message X-Antivirus-Status: Clean Sender: linux-btrfs-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-btrfs@vger.kernel.org Le 30/07/2019 à 20:52, bugzilla-daemon@bugzilla.kernel.org a écrit : > https://bugzilla.kernel.org/show_bug.cgi?id=204371 > > --- Comment #2 from Andrew Morton (akpm@linux-foundation.org) --- > (switched to email. Please respond via emailed reply-to-all, not via the > bugzilla web interface). Reply all replies to bugzilla-daemon@bugzilla.kernel.org only. [...] > > cc'ing various people here. Hum ... only got that email through the bugzilla interface, and CC'ed people don't show up. > > I suspect proc_cgroup_show() is innocent and that perhaps > bpf_prepare_filter() had a memory scribble. iirc there has been at > least one recent pretty serious bpf fix applied recently. Can others > please take a look? > > (Seriously - please don't modify this report via the bugzilla web interface!) > Haven't got the original CC'ed list, so please reply with missing Cc's if any. We have well progressed on this case. Erhard made a relation being this "Object padding overwritten" issue arising on any driver, and the presence of the BTRFS driver. Then he was able to bisect the issue to: commit 69d2480456d1baf027a86e530989d7bedd698d5f Author: David Sterba Date: Fri Jun 29 10:56:44 2018 +0200 btrfs: use copy_page for copying pages instead of memcpy Use the helper that's possibly optimized for full page copies. Signed-off-by: David Sterba After looking in the code, it has appeared that some of the said "pages" were allocated with "kzalloc()". Using the patch https://patchwork.ozlabs.org/patch/1148033/ Erhard confirmed that some btrfs functions were calling copy_page() with misaligned destinations. copy_page(), at least on powerpc, expects cache aligned destination. The patch https://patchwork.ozlabs.org/patch/1148606/ fixes the issue. Christophe --- L'absence de virus dans ce courrier électronique a été vérifiée par le logiciel antivirus Avast. https://www.avast.com/antivirus