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[70.31.26.132]) by smtp.gmail.com with ESMTPSA id fy15-20020a05622a5a0f00b003999d25e772sm898838qtb.71.2022.12.22.13.17.23 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Thu, 22 Dec 2022 13:17:24 -0800 (PST) Date: Thu, 22 Dec 2022 16:17:22 -0500 From: Peter Xu To: David Hildenbrand Cc: linux-kernel@vger.kernel.org, linux-mm@kvack.org, Andrew Morton , Mike Kravetz , Muchun Song , Miaohe Lin Subject: Re: [PATCH v1 0/2] mm/hugetlb: uffd-wp fixes for hugetlb_change_protection() Message-ID: References: <20221222205511.675832-1-david@redhat.com> MIME-Version: 1.0 In-Reply-To: <20221222205511.675832-1-david@redhat.com> X-Mimecast-Spam-Score: 0 X-Mimecast-Originator: redhat.com Content-Type: text/plain; charset=utf-8 Content-Disposition: inline X-Rspam-User: X-Rspamd-Server: rspam03 X-Rspamd-Queue-Id: 0AD1440006 X-Stat-Signature: ge1kx67hyxdnyj6z6hxtt6qhtxkeexg1 X-HE-Tag: 1671743847-762549 X-HE-Meta: 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 4C1QCx0/ M94ocqimXFeYyinuJe1/Ayr8ta3Wgvpf+zy45gEo1JJndELQCu674dtOupjthBwNOuUzAAa4otTk5AwbwDftDKl+tnDEHenRmOLPl5LVfz2zqyhZMxpCLno8FH0Ihfkp1ky52PF5y/i0yAB6CGhj38cU4Kg== 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 Thu, Dec 22, 2022 at 09:55:09PM +0100, David Hildenbrand wrote: > Playing with virtio-mem and background snapshots (using uffd-wp) on > hugetlb in QEMU, I managed to trigger a VM_BUG_ON(). Looking into the > details, hugetlb_change_protection() seems to not handle uffd-wp correctly > in all cases. > > Patch #1 fixes my test case. I don't have reproducers for patch #2, as > it requires running into migration entries. > > I did not yet check in detail yet if !hugetlb code requires similar care. > > Cc: Andrew Morton > Cc: Mike Kravetz > Cc: Peter Xu > Cc: Muchun Song > Cc: Miaohe Lin > > David Hildenbrand (2): > mm/hugetlb: fix PTE marker handling in hugetlb_change_protection() > mm/hugetlb: fix uffd-wp handling for migration entries in > hugetlb_change_protection() Reviewed-by: Peter Xu Thanks, David. -- Peter Xu