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[209.85.208.45]) by smtp.gmail.com with ESMTPSA id e15sm6855528ejh.56.2021.04.07.12.29.18 for (version=TLS1_3 cipher=TLS_AES_128_GCM_SHA256 bits=128/128); Wed, 07 Apr 2021 12:29:18 -0700 (PDT) Received: by mail-ed1-f45.google.com with SMTP id w18so22320285edc.0 for ; Wed, 07 Apr 2021 12:29:18 -0700 (PDT) X-Received: by 2002:a2e:b6c6:: with SMTP id m6mr2990148ljo.411.1617823377841; Wed, 07 Apr 2021 12:22:57 -0700 (PDT) MIME-Version: 1.0 References: <20210401181741.168763-1-surenb@google.com> In-Reply-To: From: Linus Torvalds Date: Wed, 7 Apr 2021 12:22:41 -0700 X-Gmail-Original-Message-ID: Message-ID: Subject: Re: [PATCH 0/5] 4.14 backports of fixes for "CoW after fork() issue" To: Mikulas Patocka Cc: Suren Baghdasaryan , Vlastimil Babka , Peter Xu , 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 Content-Type: text/plain; charset="UTF-8" X-Rspamd-Server: rspam03 X-Rspamd-Queue-Id: A9E5EE000108 X-Stat-Signature: ryz8agu98d3rugd931f55j8dj11e7ug6 Received-SPF: none (linuxfoundation.org>: No applicable sender policy available) receiver=imf13; identity=mailfrom; envelope-from=""; helo=mail-ed1-f45.google.com; client-ip=209.85.208.45 X-HE-DKIM-Result: pass/pass X-HE-Tag: 1617823757-116568 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 Wed, Apr 7, 2021 at 11:47 AM Mikulas Patocka wrote: > > So, we fixed it, but we don't know why. > > Peter Xu's patchset that fixed it is here: > https://lore.kernel.org/lkml/20200821234958.7896-1-peterx@redhat.com/ Yeah, that's the part that ends up being really painful to backport (with all the subsequent fixes too), so the 4.14 people would prefer to avoid it. But I think that if it's a "requires dax pmem and ptrace on top", it may simply be a non-issue for those users. Although who knows - maybe that ends up being a real issue on Android.. Linus