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=-5.8 required=3.0 tests=BAYES_00,DKIMWL_WL_HIGH, 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 9D004C433ED for ; Wed, 21 Apr 2021 21:05:26 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 7E33561430 for ; Wed, 21 Apr 2021 21:05:26 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S245728AbhDUVF6 (ORCPT ); Wed, 21 Apr 2021 17:05:58 -0400 Received: from us-smtp-delivery-124.mimecast.com ([216.205.24.124]:56556 "EHLO us-smtp-delivery-124.mimecast.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S243828AbhDUVF5 (ORCPT ); Wed, 21 Apr 2021 17:05:57 -0400 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1619039123; h=from:from:reply-to:subject:subject:date:date:message-id:message-id: to:to:cc:cc:mime-version:mime-version:content-type:content-type: in-reply-to:in-reply-to:references:references; bh=+NPvL4bnAQ0xyAmY/8IZQZjszIIYldcl5F0YQggfYA4=; b=Ch2g25Kj8YpzZUNAc+q3dN2rfGoTLfXI7UsPaDy6tGw8d+8AFhptXNn9qcKiHrImThLiiW 57R5okaIY8ZZznbOZ+ok247M1JrObOINY7LSms+z4TYxqeTj3jHO5WH+8PpRyYomS/8loV Qm0XI2EYykSVpGicoCScUJkxBgJcdB0= Received: from mail-qt1-f198.google.com (mail-qt1-f198.google.com [209.85.160.198]) (Using TLS) by relay.mimecast.com with ESMTP id us-mta-207-H4kwa-juOaiVnk6v4Bx6kA-1; Wed, 21 Apr 2021 17:05:20 -0400 X-MC-Unique: H4kwa-juOaiVnk6v4Bx6kA-1 Received: by mail-qt1-f198.google.com with SMTP id a11-20020ac85b8b0000b02901a69faebe0cso13939584qta.6 for ; Wed, 21 Apr 2021 14:05:20 -0700 (PDT) X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:date:from:to:cc:subject:message-id:references :mime-version:content-disposition:in-reply-to; bh=+NPvL4bnAQ0xyAmY/8IZQZjszIIYldcl5F0YQggfYA4=; b=hBBAOZVkhuo+EpqzqswVtCrpQecACNExpcT89PtcEyiEaEc6pJg9pQceUaBOHZ5+Xc pxd6In18IB1dw3DZsr/ECOfxqb+DgKRbhk4vvhFK67FSVuEXAy43WT/zdYNqXtBNTYMX VZhj87dMKlEu0owlwawjiBuCfpoSrrL6nOVcTNwtSLI0p0BLWJed9Quwa7j/CfJFDfY1 xK21E0CKMD3foV+58Pl2ru8FHH3zuAY8pBxRrvNBpzl2ydj1lS+sPRVKHDnCcUnGGeJm +1fE1iJYgF57JZ3UFAXow1CYn2UUgOQamiyYEUXPiyUL405romiFTNQrZrUKr3JToIP7 yCmQ== X-Gm-Message-State: AOAM531yhobW2P5HMm70RzzcliPV5jQZPXQGb8dkPR9EGJBbgfTLB6E6 BzN9sx7zuGqFntHp1hvLaRVX0Rl7TBIDvNsHUTV/WzwxpBPLkVF0qC2KbCSogc5omf5iVu8V7nZ Gmu1Aym0H9HRxYUghxahrXxWP X-Received: by 2002:a05:620a:2158:: with SMTP id m24mr137864qkm.306.1619039119806; Wed, 21 Apr 2021 14:05:19 -0700 (PDT) X-Google-Smtp-Source: ABdhPJwxujGZeCbAvz4IXpRdnt1YImSNzwwC/WEtVZvG6EHSmVIC7ejMtWkWr+rWNvTx7EvGNOhIRQ== X-Received: by 2002:a05:620a:2158:: with SMTP id m24mr137828qkm.306.1619039119514; Wed, 21 Apr 2021 14:05:19 -0700 (PDT) Received: from xz-x1 (bras-base-toroon474qw-grc-77-184-145-104-227.dsl.bell.ca. [184.145.104.227]) by smtp.gmail.com with ESMTPSA id v18sm589596qtq.38.2021.04.21.14.05.17 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Wed, 21 Apr 2021 14:05:18 -0700 (PDT) Date: Wed, 21 Apr 2021 17:05:17 -0400 From: Peter Xu To: Suren Baghdasaryan Cc: Linus Torvalds , Mikulas Patocka , Vlastimil Babka , stable , Greg Kroah-Hartman , Jann Horn , Kirill Tkhai , Shaohua Li , Nadav Amit , Linux-MM , Linux Kernel Mailing List , Android Kernel Team , Andrea Arcangeli , David Hildenbrand , Jason Gunthorpe Subject: Re: [PATCH 0/5] 4.14 backports of fixes for "CoW after fork() issue" Message-ID: <20210421210517.GA6404@xz-x1> References: <20210401181741.168763-1-surenb@google.com> MIME-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Disposition: inline In-Reply-To: Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Hi, Suren, On Wed, Apr 21, 2021 at 01:01:34PM -0700, Suren Baghdasaryan wrote: > Peter, you mentioned https://lkml.org/lkml/2020/8/10/439 patch to > distinguish real writes vs enforced COW read requests, however I also > see that you had a later version of this patch here: > https://lore.kernel.org/patchwork/patch/1286506/. Which one should I > backport? Or is it not needed in the absence of uffd-wp support in the > earlier kernels? Sorry I have no ability to evaluate the rest... but according to Linus's previous reply, my understanding is that it is not needed, not to mention it's not upstreamed too. Thanks, -- Peter Xu