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Howlett" , Vlastimil Babka Date: Fri, 19 Jun 2026 09:46:59 -0400 In-Reply-To: References: <20260616190300.1509639-1-riel@surriel.com> <20260616190300.1509639-4-riel@surriel.com> Autocrypt: addr=riel@surriel.com; prefer-encrypt=mutual; keydata=mQENBFIt3aUBCADCK0LicyCYyMa0E1lodCDUBf6G+6C5UXKG1jEYwQu49cc/gUBTTk33A eo2hjn4JinVaPF3zfZprnKMEGGv4dHvEOCPWiNhlz5RtqH3SKJllq2dpeMS9RqbMvDA36rlJIIo47 Z/nl6IA8MDhSqyqdnTY8z7LnQHqq16jAqwo7Ll9qALXz4yG1ZdSCmo80VPetBZZPw7WMjo+1hByv/ lvdFnLfiQ52tayuuC1r9x2qZ/SYWd2M4p/f5CLmvG9UcnkbYFsKWz8bwOBWKg1PQcaYHLx06sHGdY dIDaeVvkIfMFwAprSo5EFU+aes2VB2ZjugOTbkkW2aPSWTRsBhPHhV6dABEBAAG0HlJpayB2YW4gU mllbCA8cmllbEByZWRoYXQuY29tPokBHwQwAQIACQUCW5LcVgIdIAAKCRDOed6ShMTeg05SB/986o gEgdq4byrtaBQKFg5LWfd8e+h+QzLOg/T8mSS3dJzFXe5JBOfvYg7Bj47xXi9I5sM+I9Lu9+1XVb/ r2rGJrU1DwA09TnmyFtK76bgMF0sBEh1ECILYNQTEIemzNFwOWLZZlEhZFRJsZyX+mtEp/WQIygHV WjwuP69VJw+fPQvLOGn4j8W9QXuvhha7u1QJ7mYx4dLGHrZlHdwDsqpvWsW+3rsIqs1BBe5/Itz9o 6y9gLNtQzwmSDioV8KhF85VmYInslhv5tUtMEppfdTLyX4SUKh8ftNIVmH9mXyRCZclSoa6IMd635 Jq1Pj2/Lp64tOzSvN5Y9zaiCc5FucXtB9SaWsgdmFuIFJpZWwgPHJpZWxAc3VycmllbC5jb20+iQE +BBMBAgAoBQJSLd2lAhsjBQkSzAMABgsJCAcDAgYVCAIJCgsEFgIDAQIeAQIXgAAKCRDOed6ShMTe g4PpB/0ZivKYFt0LaB22ssWUrBoeNWCP1NY/lkq2QbPhR3agLB7ZXI97PF2z/5QD9Fuy/FD/jddPx KRTvFCtHcEzTOcFjBmf52uqgt3U40H9GM++0IM0yHusd9EzlaWsbp09vsAV2DwdqS69x9RPbvE/Ne fO5subhocH76okcF/aQiQ+oj2j6LJZGBJBVigOHg+4zyzdDgKM+jp0bvDI51KQ4XfxV593OhvkS3z 3FPx0CE7l62WhWrieHyBblqvkTYgJ6dq4bsYpqxxGJOkQ47WpEUx6onH+rImWmPJbSYGhwBzTo0Mm G1Nb1qGPG+mTrSmJjDRxrwf1zjmYqQreWVSFEt26tBpSaWsgdmFuIFJpZWwgPHJpZWxAZmIuY29tP okBPgQTAQIAKAUCW5LbiAIbIwUJEswDAAYLCQgHAwIGFQgCCQoLBBYCAwECHgECF4AACgkQznneko TE3oOUEQgAsrGxjTC1bGtZyuvyQPcXclap11Ogib6rQywGYu6/Mnkbd6hbyY3wpdyQii/cas2S44N cQj8HkGv91JLVE24/Wt0gITPCH3rLVJJDGQxprHTVDs1t1RAbsbp0XTksZPCNWDGYIBo2aHDwErhI omYQ0Xluo1WBtH/UmHgirHvclsou1Ks9jyTxiPyUKRfae7GNOFiX99+ZlB27P3t8CjtSO831Ij0Ip QrfooZ21YVlUKw0Wy6Ll8EyefyrEYSh8KTm8dQj4O7xxvdg865TLeLpho5PwDRF+/mR3qi8CdGbkE c4pYZQO8UDXUN4S+pe0aTeTqlYw8rRHWF9TnvtpcNzZw== Content-Type: text/plain; charset="UTF-8" Content-Transfer-Encoding: quoted-printable User-Agent: Evolution 3.56.2 (3.56.2-2.fc42) MIME-Version: 1.0 X-Stat-Signature: axpc57164pgwdzetpe35o1p3mkytpkju X-Rspamd-Server: rspam05 X-Rspamd-Queue-Id: 21CC0180006 X-Rspam-User: X-HE-Tag: 1781876840-835903 X-HE-Meta: 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 7/GeFF7B rYdlcw3pJ6+9r/ups30Gg5DfZ1V8oyjn6twtxx9xzYpLU7cx9/88l6wYCJrB7NWHEXcvEO/jNFLG7LFfUUtYLInl5tT2n0pPN2wF5IUjG3XBaG0SFMF4Rb9Rp6Jye8zOwCWe8AQj0tPfmq1WqzateEt6Zs6ceNLpnb9zYWEJ7ocER/qs2wfFnzUk2doNQa2dlQO2t7kk7lt8XOLI/9YhNLm9oz2RDxypDLaSf Sender: owner-linux-mm@kvack.org Precedence: bulk X-Loop: owner-majordomo@kvack.org List-ID: List-Subscribe: List-Unsubscribe: On Tue, 2026-06-16 at 23:19 -0700, Suren Baghdasaryan wrote: >=20 > I don't think we should be using per-VMA locks if the read spans > multiple VMAs. Doing that would risk a possibility of reading > inconsistent data since we are locking one VMA at a time. While we > load and read VMA, its neighboring VMA can be unmapped and another > one > can be mapped in its place.=20 How is that different from userspace overwriting data while we are reading it, and us reading half new, and half old contents? We already have nothing synchronizing the contents today. All our locking does is protect the metadata we use to find the memory. --=20 All Rights Reversed.