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=-4.1 required=3.0 tests=BAYES_00,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI, SPF_HELO_NONE,SPF_PASS,URIBL_BLOCKED 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 D4FF8C433E1 for ; Tue, 14 Jul 2020 18:14:07 +0000 (UTC) Received: from kanga.kvack.org (kanga.kvack.org [205.233.56.17]) by mail.kernel.org (Postfix) with ESMTP id 91CEF225AA for ; Tue, 14 Jul 2020 18:14:07 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (1024-bit key) header.d=joelfernandes.org header.i=@joelfernandes.org header.b="dq68p4Oe" DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 91CEF225AA Authentication-Results: mail.kernel.org; dmarc=none (p=none dis=none) header.from=joelfernandes.org Authentication-Results: mail.kernel.org; spf=pass smtp.mailfrom=owner-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix) id 0C30E6B0003; Tue, 14 Jul 2020 14:14:07 -0400 (EDT) Received: by kanga.kvack.org (Postfix, from userid 40) id 073156B0007; Tue, 14 Jul 2020 14:14:07 -0400 (EDT) X-Delivered-To: int-list-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix, from userid 63042) id EA4656B0008; Tue, 14 Jul 2020 14:14:06 -0400 (EDT) X-Delivered-To: linux-mm@kvack.org Received: from forelay.hostedemail.com (smtprelay0240.hostedemail.com [216.40.44.240]) by kanga.kvack.org (Postfix) with ESMTP id D7C196B0003 for ; Tue, 14 Jul 2020 14:14:06 -0400 (EDT) Received: from smtpin06.hostedemail.com (10.5.19.251.rfc1918.com [10.5.19.251]) by forelay01.hostedemail.com (Postfix) with ESMTP id 8CC1A180AD81A for ; Tue, 14 Jul 2020 18:14:06 +0000 (UTC) X-FDA: 77037480492.06.show79_0716a8026ef3 Received: from filter.hostedemail.com (10.5.16.251.rfc1918.com [10.5.16.251]) by smtpin06.hostedemail.com (Postfix) with ESMTP id DE13F100528E9 for ; Tue, 14 Jul 2020 18:12:46 +0000 (UTC) X-HE-Tag: show79_0716a8026ef3 X-Filterd-Recvd-Size: 4851 Received: from mail-il1-f195.google.com (mail-il1-f195.google.com [209.85.166.195]) by imf11.hostedemail.com (Postfix) with ESMTP for ; Tue, 14 Jul 2020 18:12:46 +0000 (UTC) Received: by mail-il1-f195.google.com with SMTP id t18so15034972ilh.2 for ; Tue, 14 Jul 2020 11:12:46 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=joelfernandes.org; s=google; h=mime-version:references:in-reply-to:from:date:message-id:subject:to :cc; bh=XgMYLghS9qV+zQ3j/AEHdigXuQT8tk2Ry048DCv3WNo=; b=dq68p4Oe6FTibRT0OKXe06CPAge1OFrmt3gile+/qSYXPHXUtOKRn0era1397ge7iu SG0nsm4H7K+6hZKM5Vkb9MlBteNDRdUG8mrLYIN7NPDfr5s5pRLh9h6UcW6OI3ZCFfXb Xd09xrFtLNw2jIxhB4wLLFDrF+rMXW9ILgVMY= X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:mime-version:references:in-reply-to:from:date :message-id:subject:to:cc; bh=XgMYLghS9qV+zQ3j/AEHdigXuQT8tk2Ry048DCv3WNo=; b=PYi0FW5WnSV4YKkmqO8LjDh3lclQ/NRLjo1r3GpDept6k4K/Vl4+VQovajzYpTEftD 8/E6uESDS4kDghSbLIs6mLapPwSAsQ7y6YEVeF+mylz0DS+J+Axoc0LEZeIZZQirYUNc 5t3g4viG3lYUvk6kh2WSt4kc354dY40SgCwbO6K3RorxuNv+yFGiqJDLQnH/A87N0JJu ip3LGXScqfWA0IbSFH14xSrlxE7aTd14aIwrUMFjxyNqD5UPPr24CqEFcIe0P3jl9x2M 5gTwW4xjPK5K980U4JhgMGTZuMxx4DzTovm8yHbAAJca1U2uSGXevcPuZh4miHG0b5/h 4t4g== X-Gm-Message-State: AOAM532au61c1MGy/pFGpWXCbs6r9YF8ZE+9m6z4B91JZcMPvTz11B+9 5vRW5R9ChflNeAKfeTQuLkSh4rF+JBsVSBjys6Dvdg== X-Google-Smtp-Source: ABdhPJxZh9UtdKz/96YNIgTICaWWllWK6qo3ibzuoBpQ/DEDx3DUR9Zka1P+EnolKivtnMEOWWuJNr7z5hjeAlsuqI0= X-Received: by 2002:a92:cf42:: with SMTP id c2mr6263546ilr.13.1594750365698; Tue, 14 Jul 2020 11:12:45 -0700 (PDT) MIME-Version: 1.0 References: <20200712215041.GA3644504@google.com> <20200714073306.kq4zikkphqje2yzb@box> <20200714160843.GA1685150@google.com> In-Reply-To: From: Joel Fernandes Date: Tue, 14 Jul 2020 14:12:33 -0400 Message-ID: Subject: Re: WARNING: at mm/mremap.c:211 move_page_tables in i386 To: Linus Torvalds Cc: "Kirill A. Shutemov" , Naresh Kamboju , linux- stable , open list , linux-mm , Arnd Bergmann , Andrew Morton , Roman Gushchin , Michal Hocko , lkft-triage@lists.linaro.org, Chris Down , Michel Lespinasse , Fan Yang , Brian Geffon , Anshuman Khandual , Will Deacon , Catalin Marinas , pugaowei@gmail.com, Jerome Glisse , Greg Kroah-Hartman , Mel Gorman , Hugh Dickins , Al Viro , Tejun Heo , Sasha Levin Content-Type: text/plain; charset="UTF-8" X-Rspamd-Queue-Id: DE13F100528E9 X-Spamd-Result: default: False [0.00 / 100.00] X-Rspamd-Server: rspam01 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 Tue, Jul 14, 2020 at 12:11 PM Linus Torvalds wrote: > > On Tue, Jul 14, 2020 at 9:08 AM Joel Fernandes wrote: > > > > I was thinking we should not call move_page_tables() with overlapping ranges > > at all, just to keep things simple. > > No, we're not breaking the existing stack movement code just to keep > things simple. > > The rule is "make it as simple as possible, but no simpler". > > And "as possible" in the case of Linux means "no breaking of old > interfaces". The stack randomization movement most certainly counts. Hi Linus, I think you misunderstood me. I was not advocating breaking the stack movement code or breaking stack randomization, I was going to try to see if I could keep that working while not having to do an overlapping move. That would be what I would do in the future patch (until which as you mentioned, you would switch the WARN_ON to WARN_ON_ONCE). I agree with you that we keep things as simple as possible while not breaking functionality. Cheers, - Joel