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Peter Anvin" , Mike Rapoport , Lorenzo Stoakes , Pedro Falcato , Toshi Kani , linux-mm@kvack.org, regressions@lists.linux.dev, linux-kernel@vger.kernel.org References: <20260923223116.20090-1-mikhail.v.gavrilov@gmail.com> From: Dave Hansen Content-Language: en-US Autocrypt: addr=dave.hansen@intel.com; keydata= xsFNBE6HMP0BEADIMA3XYkQfF3dwHlj58Yjsc4E5y5G67cfbt8dvaUq2fx1lR0K9h1bOI6fC oAiUXvGAOxPDsB/P6UEOISPpLl5IuYsSwAeZGkdQ5g6m1xq7AlDJQZddhr/1DC/nMVa/2BoY 2UnKuZuSBu7lgOE193+7Uks3416N2hTkyKUSNkduyoZ9F5twiBhxPJwPtn/wnch6n5RsoXsb ygOEDxLEsSk/7eyFycjE+btUtAWZtx+HseyaGfqkZK0Z9bT1lsaHecmB203xShwCPT49Blxz VOab8668QpaEOdLGhtvrVYVK7x4skyT3nGWcgDCl5/Vp3TWA4K+IofwvXzX2ON/Mj7aQwf5W iC+3nWC7q0uxKwwsddJ0Nu+dpA/UORQWa1NiAftEoSpk5+nUUi0WE+5DRm0H+TXKBWMGNCFn c6+EKg5zQaa8KqymHcOrSXNPmzJuXvDQ8uj2J8XuzCZfK4uy1+YdIr0yyEMI7mdh4KX50LO1 pmowEqDh7dLShTOif/7UtQYrzYq9cPnjU2ZW4qd5Qz2joSGTG9eCXLz5PRe5SqHxv6ljk8mb ApNuY7bOXO/A7T2j5RwXIlcmssqIjBcxsRRoIbpCwWWGjkYjzYCjgsNFL6rt4OL11OUF37wL QcTl7fbCGv53KfKPdYD5hcbguLKi/aCccJK18ZwNjFhqr4MliQARAQABzUVEYXZpZCBDaHJp c3RvcGhlciBIYW5zZW4gKEludGVsIFdvcmsgQWRkcmVzcykgPGRhdmUuaGFuc2VuQGludGVs LmNvbT7CwXgEEwECACIFAlQ+9J0CGwMGCwkIBwMCBhUIAgkKCwQWAgMBAh4BAheAAAoJEGg1 lTBwyZKwLZUP/0dnbhDc229u2u6WtK1s1cSd9WsflGXGagkR6liJ4um3XCfYWDHvIdkHYC1t MNcVHFBwmQkawxsYvgO8kXT3SaFZe4ISfB4K4CL2qp4JO+nJdlFUbZI7cz/Td9z8nHjMcWYF IQuTsWOLs/LBMTs+ANumibtw6UkiGVD3dfHJAOPNApjVr+M0P/lVmTeP8w0uVcd2syiaU5jB aht9CYATn+ytFGWZnBEEQFnqcibIaOrmoBLu2b3fKJEd8Jp7NHDSIdrvrMjYynmc6sZKUqH2 I1qOevaa8jUg7wlLJAWGfIqnu85kkqrVOkbNbk4TPub7VOqA6qG5GCNEIv6ZY7HLYd/vAkVY E8Plzq/NwLAuOWxvGrOl7OPuwVeR4hBDfcrNb990MFPpjGgACzAZyjdmYoMu8j3/MAEW4P0z F5+EYJAOZ+z212y1pchNNauehORXgjrNKsZwxwKpPY9qb84E3O9KYpwfATsqOoQ6tTgr+1BR CCwP712H+E9U5HJ0iibN/CDZFVPL1bRerHziuwuQuvE0qWg0+0SChFe9oq0KAwEkVs6ZDMB2 P16MieEEQ6StQRlvy2YBv80L1TMl3T90Bo1UUn6ARXEpcbFE0/aORH/jEXcRteb+vuik5UGY 5TsyLYdPur3TXm7XDBdmmyQVJjnJKYK9AQxj95KlXLVO38lczsFNBFRjzmoBEACyAxbvUEhd GDGNg0JhDdezyTdN8C9BFsdxyTLnSH31NRiyp1QtuxvcqGZjb2trDVuCbIzRrgMZLVgo3upr MIOx1CXEgmn23Zhh0EpdVHM8IKx9Z7V0r+rrpRWFE8/wQZngKYVi49PGoZj50ZEifEJ5qn/H Nsp2+Y+bTUjDdgWMATg9DiFMyv8fvoqgNsNyrrZTnSgoLzdxr89FGHZCoSoAK8gfgFHuO54B lI8QOfPDG9WDPJ66HCodjTlBEr/Cwq6GruxS5i2Y33YVqxvFvDa1tUtl+iJ2SWKS9kCai2DR 3BwVONJEYSDQaven/EHMlY1q8Vln3lGPsS11vSUK3QcNJjmrgYxH5KsVsf6PNRj9mp8Z1kIG qjRx08+nnyStWC0gZH6NrYyS9rpqH3j+hA2WcI7De51L4Rv9pFwzp161mvtc6eC/GxaiUGuH BNAVP0PY0fqvIC68p3rLIAW3f97uv4ce2RSQ7LbsPsimOeCo/5vgS6YQsj83E+AipPr09Caj 0hloj+hFoqiticNpmsxdWKoOsV0PftcQvBCCYuhKbZV9s5hjt9qn8CE86A5g5KqDf83Fxqm/ vXKgHNFHE5zgXGZnrmaf6resQzbvJHO0Fb0CcIohzrpPaL3YepcLDoCCgElGMGQjdCcSQ+Ci FCRl0Bvyj1YZUql+ZkptgGjikQARAQABwsFfBBgBAgAJBQJUY85qAhsMAAoJEGg1lTBwyZKw l4IQAIKHs/9po4spZDFyfDjunimEhVHqlUt7ggR1Hsl/tkvTSze8pI1P6dGp2XW6AnH1iayn yRcoyT0ZJ+Zmm4xAH1zqKjWplzqdb/dO28qk0bPso8+1oPO8oDhLm1+tY+cOvufXkBTm+whm +AyNTjaCRt6aSMnA/QHVGSJ8grrTJCoACVNhnXg/R0g90g8iV8Q+IBZyDkG0tBThaDdw1B2l asInUTeb9EiVfL/Zjdg5VWiF9LL7iS+9hTeVdR09vThQ/DhVbCNxVk+DtyBHsjOKifrVsYep WpRGBIAu3bK8eXtyvrw1igWTNs2wazJ71+0z2jMzbclKAyRHKU9JdN6Hkkgr2nPb561yjcB8 sIq1pFXKyO+nKy6SZYxOvHxCcjk2fkw6UmPU6/j/nQlj2lfOAgNVKuDLothIxzi8pndB8Jju KktE5HJqUUMXePkAYIxEQ0mMc8Po7tuXdejgPMwgP7x65xtfEqI0RuzbUioFltsp1jUaRwQZ MTsCeQDdjpgHsj+P2ZDeEKCbma4m6Ez/YWs4+zDm1X8uZDkZcfQlD9NldbKDJEXLIjYWo1PH hYepSffIWPyvBMBTW2W5FRjJ4vLRrJSUoEfJuPQ3vW9Y73foyo/qFoURHO48AinGPZ7PC7TF vUaNOTjKedrqHkaOcqB185ahG2had0xnFsDPlx5y In-Reply-To: <20260923223116.20090-1-mikhail.v.gavrilov@gmail.com> Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 7bit X-Rspamd-Server: rspam05 X-Rspamd-Queue-Id: AE99520008 X-Stat-Signature: fzbgec58556xwiuh7tewcrn4j6qa46io X-Rspam-User: X-HE-Tag: 1790204824-976992 X-HE-Meta: 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 kgVUSg69 9NfxyGGqQiIyBBPBlqVrP8boxOovlmWOQjdRA9lepW9VM+HPAWwBbw7SsOO3plDwbDnJ++8gSLajeKrdX5TeiPzkVhXDcgGtHKmfBhZ92MKIwcwz2MtJJn60CiyByGqXwmi0YI2WtCLL+AShx0GqTRrb8VyDCJOFddMd5RXmqGCf2xBaG+vOdZx4ECZAsX7GtlQEW85FPJWMeyDMkDFh5obXgjyh+zX6/2/fo2mhVxtOamd/tgpSQrNgHfbFTlHaQJIDJI5wBFzg1yhNktwbHj3mDxIcwcFJ+iCDWb1GWj7WUnjM4K64PM5Lkp/gi+LcSIxK9VrTUrJmotmg= Sender: owner-linux-mm@kvack.org Precedence: bulk X-Loop: owner-majordomo@kvack.org List-ID: List-Subscribe: List-Unsubscribe: On 9/23/26 15:31, Mikhail Gavrilov wrote: > So clear the PUD, flush, and free the PTE tables straight from the > detached PMD table - the same order pmd_free_pte_page() uses one level > down. With no allocation left the cycle is gone, and so is the only way > this function could fail. Yeah, I basically agree with your analysis and fix. There are a few things we need to figure out like having pmd_free_pte_page() return 'int' when it doesn't ever fail, the comments, and the reverse Christmas tree. I'll dig into it a bit tomorrow and see what I come up with.