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The subroutine which handled this failed to take into account the presence of 1GB largepage mappings created using the shm_create_largepage(3) interface.  In particular, it would always treat a page directory page entry as pointing to another page table page.\n\nThe bug can be abused by an unprivileged user to cause pmap_pkru_update_range() to treat userspace memory as a page table page, and thus overwrite memory to which the application would otherwise not have access.","Type":"Description","Title":"Missing large page handling in pmap_pkru_update_range()"}]}}}