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=-2.2 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS,USER_AGENT_SANE_1 autolearn=no 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 0B462C432C1 for ; Tue, 24 Sep 2019 20:52:54 +0000 (UTC) Received: from kanga.kvack.org (kanga.kvack.org [205.233.56.17]) by mail.kernel.org (Postfix) with ESMTP id C797A2168B for ; Tue, 24 Sep 2019 20:52:53 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org C797A2168B Authentication-Results: mail.kernel.org; dmarc=none (p=none dis=none) header.from=linux.com Authentication-Results: mail.kernel.org; spf=pass smtp.mailfrom=owner-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix) id 676F36B0007; Tue, 24 Sep 2019 16:52:53 -0400 (EDT) Received: by kanga.kvack.org (Postfix, from userid 40) id 64CCA6B0008; Tue, 24 Sep 2019 16:52:53 -0400 (EDT) X-Delivered-To: int-list-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix, from userid 63042) id 5B1426B000A; Tue, 24 Sep 2019 16:52:53 -0400 (EDT) X-Delivered-To: linux-mm@kvack.org Received: from forelay.hostedemail.com (smtprelay0207.hostedemail.com [216.40.44.207]) by kanga.kvack.org (Postfix) with ESMTP id 3FE286B0007 for ; Tue, 24 Sep 2019 16:52:53 -0400 (EDT) Received: from smtpin01.hostedemail.com (10.5.19.251.rfc1918.com [10.5.19.251]) by forelay02.hostedemail.com (Postfix) with SMTP id CC5AA6D82 for ; Tue, 24 Sep 2019 20:52:52 +0000 (UTC) X-FDA: 75971013384.01.week17_3638cd6292f33 X-HE-Tag: week17_3638cd6292f33 X-Filterd-Recvd-Size: 2472 Received: from gentwo.org (gentwo.org [3.19.106.255]) by imf48.hostedemail.com (Postfix) with ESMTP for ; Tue, 24 Sep 2019 20:52:52 +0000 (UTC) Received: by gentwo.org (Postfix, from userid 1002) id 1036D3E9FC; Tue, 24 Sep 2019 20:52:52 +0000 (UTC) Received: from localhost (localhost [127.0.0.1]) by gentwo.org (Postfix) with ESMTP id 0F13B3E9E5; Tue, 24 Sep 2019 20:52:52 +0000 (UTC) Date: Tue, 24 Sep 2019 20:52:52 +0000 (UTC) From: cl@linux.com X-X-Sender: cl@www.lameter.com To: David Sterba cc: Vlastimil Babka , Andrew Morton , linux-mm@kvack.org, linux-kernel@vger.kernel.org, Pekka Enberg , David Rientjes , Ming Lei , Dave Chinner , Matthew Wilcox , "Darrick J . Wong" , Christoph Hellwig , linux-xfs@vger.kernel.org, linux-fsdevel@vger.kernel.org, linux-block@vger.kernel.org, James Bottomley , linux-btrfs@vger.kernel.org, Roman Gushchin , Johannes Weiner Subject: Re: [PATCH v2 2/2] mm, sl[aou]b: guarantee natural alignment for kmalloc(power-of-two) In-Reply-To: <20190923171710.GN2751@twin.jikos.cz> Message-ID: References: <20190826111627.7505-1-vbabka@suse.cz> <20190826111627.7505-3-vbabka@suse.cz> <20190923171710.GN2751@twin.jikos.cz> User-Agent: Alpine 2.21 (DEB 202 2017-01-01) MIME-Version: 1.0 Content-Type: text/plain; charset=US-ASCII X-Bogosity: Ham, tests=bogofilter, spamicity=0.000000, version=1.2.4 Sender: owner-linux-mm@kvack.org Precedence: bulk X-Loop: owner-majordomo@kvack.org List-ID: On Mon, 23 Sep 2019, David Sterba wrote: > As a user of the allocator interface in filesystem, I'd like to see a > more generic way to address the alignment guarantees so we don't have to > apply workarounds like 3acd48507dc43eeeb each time we find that we > missed something. (Where 'missed' might be another sort of weird memory > corruption hard to trigger.) The alignment guarantees are clearly documented and objects are misaligned in debugging kernels. Looking at 3acd48507dc43eeeb:Looks like no one tested that patch with a debug kernel or full debugging on until it hit mainline. Not good. The consequence for the lack of proper testing is to make the production kernel contain the debug measures?