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Wed, 16 Mar 2022 17:11:50 -0700 (PDT) X-Google-Smtp-Source: ABdhPJz9NNWbYnnVvQ5V6vyo2WvlkekJzDgzdWMeVliKNTwPzm7bGsDML7f17IzKO/fTp5HlEYS2mA== X-Received: by 2002:a05:6a00:a8b:b0:4cd:6030:4df3 with SMTP id b11-20020a056a000a8b00b004cd60304df3mr2025154pfl.40.1647475909736; Wed, 16 Mar 2022 17:11:49 -0700 (PDT) Received: from xz-m1.local ([191.101.132.230]) by smtp.gmail.com with ESMTPSA id mq6-20020a17090b380600b001c6357f146csm7766127pjb.12.2022.03.16.17.11.46 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Wed, 16 Mar 2022 17:11:49 -0700 (PDT) Date: Thu, 17 Mar 2022 08:11:44 +0800 From: Peter Xu To: Andrew Morton Cc: Nadav Amit , Linux-MM , Mike Rapoport , Andrea Arcangeli , stable@vger.kernel.org Subject: Re: [PATCH] userfaultfd: mark uffd_wp regardless of VM_WRITE flag Message-ID: References: <20220217211602.2769-1-namit@vmware.com> <68B04C0D-F8CE-4C95-9032-CF703436DC99@gmail.com> <3E9C755C-7335-4636-8280-D5CB9735A76A@gmail.com> <20220316150553.c7b6f9e0eac620c9ee5963a5@linux-foundation.org> MIME-Version: 1.0 In-Reply-To: <20220316150553.c7b6f9e0eac620c9ee5963a5@linux-foundation.org> X-Mimecast-Spam-Score: 0 X-Mimecast-Originator: redhat.com Content-Type: text/plain; charset=utf-8 Content-Disposition: inline X-Rspamd-Queue-Id: D4AA7C0013 X-Rspam-User: Authentication-Results: imf28.hostedemail.com; dkim=pass header.d=redhat.com header.s=mimecast20190719 header.b=aO5ccl1V; dmarc=pass (policy=none) header.from=redhat.com; spf=none (imf28.hostedemail.com: domain of peterx@redhat.com has no SPF policy when checking 170.10.129.124) smtp.mailfrom=peterx@redhat.com X-Stat-Signature: c7dstm34x3cqco7zmj4yyiq9n94y3zu5 X-Rspamd-Server: rspam04 X-HE-Tag: 1647475912-875562 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, Andrew, On Wed, Mar 16, 2022 at 03:05:53PM -0700, Andrew Morton wrote: > > As I understand it, this patch (below) is still good to merge upstream, > although Peter hasn't acked it (please). Thanks for asking. I didn't ack because I saw that it's queued a long time ago into -mm, and also it's in -next for a long time too (my new uffd-wp patchset is rebased to this one already). I normally assume that means you read and ack that patch already, so if I didn't see anything obviously wrong I'll just keep silent. Please let me know if that's not the expected behavior.. So here it is.. Acked-by: Peter Xu > > And a whole bunch of followup patches are being thought about, but have > yet to eventuate. Is there a pointer/subject? > > Do we feel that this patch warrants the cc:stable? I'm suspecting > "no", as it isn't clear that the use-case is really legitimate at this > time? Right. Uffd-wp+mprotect usage is IMHO not a major use case for uffd-wp per my knowledge. At least I didn't even expect both work together, not until Nadav started working on some of the problems.. Said that, for this specific case it should be literally only changing the behavior of anonymous UFFD-WP && !WRITE case but nothing else (please correct me otherwise..), then IMHO it's pretty safe to copy stable too especially for the cleanly applicable branches. Thanks, -- Peter Xu