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[209.85.220.65]) by mx.google.com with SMTPS id d8sor18839834pgc.51.2019.02.26.06.39.19 for (Google Transport Security); Tue, 26 Feb 2019 06:39:19 -0800 (PST) Received-SPF: pass (google.com: domain of andreyknvl@google.com designates 209.85.220.65 as permitted sender) client-ip=209.85.220.65; Authentication-Results: mx.google.com; dkim=pass header.i=@google.com header.s=20161025 header.b=qrniw8KQ; spf=pass (google.com: domain of andreyknvl@google.com designates 209.85.220.65 as permitted sender) smtp.mailfrom=andreyknvl@google.com; dmarc=pass (p=REJECT sp=REJECT dis=NONE) header.from=google.com DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=google.com; s=20161025; h=mime-version:references:in-reply-to:from:date:message-id:subject:to :cc; bh=dfiBLpo8ppzHN31Df3pK9Pue7IUmmemEwHEq/+qIHW8=; b=qrniw8KQBsnVcBdkLwXYTHP1tzALWjLL3wqY47zLDB86u7VpyXqsBCFNMPUvx2rcQ5 tleEIn43VcQEIxdaz5Lq3qoXKxfo59ovHYPtXDa7JwcKInE8AMfYDGNxNizwMWMWQjde EhSO6jW2VXILtMDY8JQSd+bipZZVCQ+CR0EOZ2zJgqQHGK2gbFfefcVUCOF/9F/FdN4j khe0Gzu8tDmq3gffWUNVCHAG7gYifd/AMvfrRv8bNWrE6v7GDGV6bjcxEvsAriDj0zwX 9ukzSjG/hOjO6EfG3Aixqm8fiGMNQyIAiftpSDpkdyIWPy343s9BUOUiQ9YAblVGHraC nJQA== X-Google-Smtp-Source: AHgI3IbzQ3IeJ3DdtureLg8xHbfzWl4k26RcwSMIdPdFZQbQ2oXfH0JWdLJfU9vlDhlDrZoE5TP5lbkNIdumuA65DBY= X-Received: by 2002:a65:6651:: with SMTP id z17mr23465185pgv.95.1551191958932; Tue, 26 Feb 2019 06:39:18 -0800 (PST) MIME-Version: 1.0 References: <8343cd77ca301df15839796f3b446b75ce5ffbbf.1550839937.git.andreyknvl@google.com> <73f2f3fe-9a66-22a1-5aae-c282779a75f5@intel.com> In-Reply-To: <73f2f3fe-9a66-22a1-5aae-c282779a75f5@intel.com> From: Andrey Konovalov Date: Tue, 26 Feb 2019 15:39:08 +0100 Message-ID: Subject: Re: [PATCH v10 07/12] fs, arm64: untag user pointers in fs/userfaultfd.c To: Dave Hansen Cc: Catalin Marinas , Will Deacon , Mark Rutland , Robin Murphy , Kees Cook , Kate Stewart , Greg Kroah-Hartman , Andrew Morton , Ingo Molnar , "Kirill A . Shutemov" , Shuah Khan , Vincenzo Frascino , Linux ARM , "open list:DOCUMENTATION" , Linux Memory Management List , linux-arch , "open list:KERNEL SELFTEST FRAMEWORK" , LKML , Dmitry Vyukov , Kostya Serebryany , Evgeniy Stepanov , Lee Smith , Ramana Radhakrishnan , Jacob Bramley , Ruben Ayrapetyan , Chintan Pandya , Luc Van Oostenryck , Dave Martin , Kevin Brodsky , Szabolcs Nagy Content-Type: text/plain; charset="UTF-8" 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 Sat, Feb 23, 2019 at 12:06 AM Dave Hansen wrote: > > On 2/22/19 4:53 AM, Andrey Konovalov wrote: > > userfaultfd_register() and userfaultfd_unregister() use provided user > > pointers for vma lookups, which can only by done with untagged pointers. > > So, we have to patch all these sites before the tagged values get to the > point of hitting the vma lookup functions. Dumb question: Why don't we > just patch the vma lookup functions themselves instead of all of these > callers? That might be a working approach as well. We'll still need to fix up places where the vma fields are accessed directly. Catalin, what do you think?