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[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 In-Reply-To: Authentication-Results: relay.mimecast.com; auth=pass smtp.auth=CUSA124A263 smtp.mailfrom=peterx@redhat.com X-Mimecast-Spam-Score: 0 X-Mimecast-Originator: redhat.com Content-Type: text/plain; charset=utf-8 Content-Disposition: inline X-Rspamd-Server: rspam05 X-Rspamd-Queue-Id: 7CE52A0000FF X-Stat-Signature: tunryf478y9xcs7uheds8xqm95jrasr5 Received-SPF: none (redhat.com>: No applicable sender policy available) receiver=imf23; identity=mailfrom; envelope-from=""; helo=us-smtp-delivery-124.mimecast.com; client-ip=216.205.24.124 X-HE-DKIM-Result: pass/pass X-HE-Tag: 1619039125-292621 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: 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