{"id":"CVE-2022-48897","summary":"arm64/mm: fix incorrect file_map_count for invalid pmd","details":"In the Linux kernel, the following vulnerability has been resolved:\n\narm64/mm: fix incorrect file_map_count for invalid pmd\n\nThe page table check trigger BUG_ON() unexpectedly when split hugepage:\n\n ------------[ cut here ]------------\n kernel BUG at mm/page_table_check.c:119!\n Internal error: Oops - BUG: 00000000f2000800 [#1] SMP\n Dumping ftrace buffer:\n    (ftrace buffer empty)\n Modules linked in:\n CPU: 7 PID: 210 Comm: transhuge-stres Not tainted 6.1.0-rc3+ #748\n Hardware name: linux,dummy-virt (DT)\n pstate: 20000005 (nzCv daif -PAN -UAO -TCO -DIT -SSBS BTYPE=--)\n pc : page_table_check_set.isra.0+0x398/0x468\n lr : page_table_check_set.isra.0+0x1c0/0x468\n[...]\n Call trace:\n  page_table_check_set.isra.0+0x398/0x468\n  __page_table_check_pte_set+0x160/0x1c0\n  __split_huge_pmd_locked+0x900/0x1648\n  __split_huge_pmd+0x28c/0x3b8\n  unmap_page_range+0x428/0x858\n  unmap_single_vma+0xf4/0x1c8\n  zap_page_range+0x2b0/0x410\n  madvise_vma_behavior+0xc44/0xe78\n  do_madvise+0x280/0x698\n  __arm64_sys_madvise+0x90/0xe8\n  invoke_syscall.constprop.0+0xdc/0x1d8\n  do_el0_svc+0xf4/0x3f8\n  el0_svc+0x58/0x120\n  el0t_64_sync_handler+0xb8/0xc0\n  el0t_64_sync+0x19c/0x1a0\n[...]\n\nOn arm64, pmd_leaf() will return true even if the pmd is invalid due to\npmd_present_invalid() check. So in pmdp_invalidate() the file_map_count\nwill not only decrease once but also increase once. Then in set_pte_at(),\nthe file_map_count increase again, and so trigger BUG_ON() unexpectedly.\n\nAdd !pmd_present_invalid() check in pmd_user_accessible_page() to fix the\nproblem.","modified":"2026-08-12T03:51:27.443908182Z","published":"2024-08-21T06:10:29.785Z","database_specific":{"osv_generated_from":"https://github.com/CVEProject/cvelistV5/tree/main/cves/2022/48xxx/CVE-2022-48897.json","cna_assigner":"Linux"},"references":[{"type":"WEB","url":"https://git.kernel.org/stable/c/21e5eca0ac9046da9918a919bc92b7b5a78d27e7"},{"type":"WEB","url":"https://git.kernel.org/stable/c/74c2f81054510d45b813548cb0a1c4ebf87cdd5f"},{"type":"ADVISORY","url":"https://github.com/CVEProject/cvelistV5/tree/main/cves/2022/48xxx/CVE-2022-48897.json"},{"type":"ADVISORY","url":"https://nvd.nist.gov/vuln/detail/CVE-2022-48897"},{"type":"PACKAGE","url":"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git"}],"affected":[{"ranges":[{"type":"GIT","repo":"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git","events":[{"introduced":"42b2547137f5c974bb1bfd657c869fe96b96d86f"},{"fixed":"21e5eca0ac9046da9918a919bc92b7b5a78d27e7"},{"fixed":"74c2f81054510d45b813548cb0a1c4ebf87cdd5f"}]}],"database_specific":{"source":"https://storage.googleapis.com/cve-osv-conversion/osv-output/CVE-2022-48897.json"}},{"package":{"name":"Kernel","ecosystem":"Linux"},"ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"5.19.0"},{"fixed":"6.1.7"}]}],"database_specific":{"source":"https://storage.googleapis.com/cve-osv-conversion/osv-output/CVE-2022-48897.json"}}],"schema_version":"1.9.0"}