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Tue, 13 Aug 2024 13:44:50 -0700 (PDT) MIME-Version: 1.0 References: <20240813-uffd-thp-flip-fix-v2-0-5efa61078a41@google.com> <20240813-uffd-thp-flip-fix-v2-1-5efa61078a41@google.com> <2e14537b-cf91-479d-a665-c3e174cf2c66@redhat.com> In-Reply-To: <2e14537b-cf91-479d-a665-c3e174cf2c66@redhat.com> From: Jann Horn Date: Tue, 13 Aug 2024 22:44:10 +0200 Message-ID: Subject: Re: [PATCH v2 1/2] userfaultfd: Fix checks for huge PMDs To: David Hildenbrand Cc: Andrew Morton , Pavel Emelianov , Andrea Arcangeli , Hugh Dickins , linux-mm@kvack.org, linux-kernel@vger.kernel.org, Qi Zheng , stable@vger.kernel.org Content-Type: text/plain; charset="UTF-8" Content-Transfer-Encoding: quoted-printable X-Rspamd-Server: rspam03 X-Rspam-User: X-Rspamd-Queue-Id: AECA140011 X-Stat-Signature: oieymudjtfp8sm4p3dn5pcyjeu996tqo X-HE-Tag: 1723581892-552326 X-HE-Meta: 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 NmNS/VIB 08jfOJsFWk6MFoZa9pNnn5kLmfL/2Hq06AHVRdWc+Edi1hEgWvjpbHUqUtbbGjdhs8f7WyBGkm+HqgQdM6ip3kLluY+XnrQnvANER5S/MB+nLcs8T5zDijL1PDKSl3cZuQFXTJT244yg4gYY3w2s9Mw2LY3aL/Jdxiyfgm2v7meKsk/a48oRs7UfOGkKV8hbvijug X-Bogosity: Ham, tests=bogofilter, spamicity=0.087347, version=1.2.4 Sender: owner-linux-mm@kvack.org Precedence: bulk X-Loop: owner-majordomo@kvack.org List-ID: List-Subscribe: List-Unsubscribe: On Tue, Aug 13, 2024 at 10:37=E2=80=AFPM David Hildenbrand wrote: > On 13.08.24 22:25, Jann Horn wrote: > > + if (unlikely(!pmd_present(dst_pmdval) || pmd_trans_huge(d= st_pmdval) || > > + pmd_devmap(dst_pmdval))) { > > Likely in the future we should turn the latter part into a "pmd_leaf()" > check. Yeah, it'd be a good idea to refactor that as a followup.