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From: Lance Yang In-Reply-To: <20260705131231.1499198-1-usama.arif@linux.dev> Content-Type: text/plain; charset=UTF-8; format=flowed Content-Transfer-Encoding: 7bit X-Migadu-Flow: FLOW_OUT X-Rspam-User: X-Rspamd-Server: rspam05 X-Rspamd-Queue-Id: A91E9140008 X-Stat-Signature: ud7ceysap7ftd3ns37dx77uwx1uyn693 X-HE-Tag: 1783304296-953425 X-HE-Meta: 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 x31V9jjY xNTCtHPmItDHWqHL8Q0X7SWyhWNV1GO1IBSJkbWBJ5OyWNxPYdsD7Fwa2UQACc+/XIpA34xM19+EgJ1NAmHoNl51F3tRYA2NDl3Fhb8BVsd3fFe35dyv+LZLPZGNdQgPDze4ytJRHceq7mmd0XgopzIqoNnUfWw6YXOrCxhphzdbN1xSl6O2HshHzK+hQzc4GJzwgJ0WvAqi2BN0Mi5ZXXtGdlFvnMukbUAgLsZfpwV+Y4rQPLfpuMjGBczS1ridFO+buBB9Iblt+F4eO7LREaSRjmCfTlZJtoQ3k8GceRPkg/nEEYG1LhqubyxGiJKxi4aViWrah3El3cp9qLb9rrELGFQ== Sender: owner-linux-mm@kvack.org Precedence: bulk X-Loop: owner-majordomo@kvack.org List-ID: List-Subscribe: List-Unsubscribe: On 2026/7/5 21:12, Usama Arif wrote: > move_pages_huge_pmd() snapshots src_pmdval under src_ptl, drops the lock, > and, for migration entries, waits with pmd_migration_entry_wait(). > > Passing &src_pmdval is wrong. pmd_migration_entry_wait() must lock and > re-read the real page-table PMD; on split-PMD-lock kernels, a stack > address also resolves to the wrong lock. softleaf_entry_wait_on_locked() Well spotted! > then waits without a folio reference, which is safe only while serialized > against migration-entry removal by the real PT lock. > > Pass src_pmd, matching __handle_mm_fault() and hmm_vma_walk_pmd(). > > Reported-by: sashiko-bot > Link: https://sashiko.dev/#/patchset/20260703173903.3789516-1-usama.arif%40linux.dev?part=8 > Fixes: adef440691ba ("userfaultfd: UFFDIO_MOVE uABI") > Signed-off-by: Usama Arif > --- As Andrew and Baolin pointed out, this should go to stable ;) With that, Reviewed-by: Lance Yang