{"id":"CVE-2025-39845","summary":"x86/mm/64: define ARCH_PAGE_TABLE_SYNC_MASK and arch_sync_kernel_mappings()","details":"In the Linux kernel, the following vulnerability has been resolved:\n\nx86/mm/64: define ARCH_PAGE_TABLE_SYNC_MASK and arch_sync_kernel_mappings()\n\nDefine ARCH_PAGE_TABLE_SYNC_MASK and arch_sync_kernel_mappings() to ensure\npage tables are properly synchronized when calling p*d_populate_kernel().\n\nFor 5-level paging, synchronization is performed via\npgd_populate_kernel().  In 4-level paging, pgd_populate() is a no-op, so\nsynchronization is instead performed at the P4D level via\np4d_populate_kernel().\n\nThis fixes intermittent boot failures on systems using 4-level paging and\na large amount of persistent memory:\n\n  BUG: unable to handle page fault for address: ffffe70000000034\n  #PF: supervisor write access in kernel mode\n  #PF: error_code(0x0002) - not-present page\n  PGD 0 P4D 0\n  Oops: 0002 [#1] SMP NOPTI\n  RIP: 0010:__init_single_page+0x9/0x6d\n  Call Trace:\n   \u003cTASK\u003e\n   __init_zone_device_page+0x17/0x5d\n   memmap_init_zone_device+0x154/0x1bb\n   pagemap_range+0x2e0/0x40f\n   memremap_pages+0x10b/0x2f0\n   devm_memremap_pages+0x1e/0x60\n   dev_dax_probe+0xce/0x2ec [device_dax]\n   dax_bus_probe+0x6d/0xc9\n   [... snip ...]\n   \u003c/TASK\u003e\n\nIt also fixes a crash in vmemmap_set_pmd() caused by accessing vmemmap\nbefore sync_global_pgds() [1]:\n\n  BUG: unable to handle page fault for address: ffffeb3ff1200000\n  #PF: supervisor write access in kernel mode\n  #PF: error_code(0x0002) - not-present page\n  PGD 0 P4D 0\n  Oops: Oops: 0002 [#1] PREEMPT SMP NOPTI\n  Tainted: [W]=WARN\n  RIP: 0010:vmemmap_set_pmd+0xff/0x230\n   \u003cTASK\u003e\n   vmemmap_populate_hugepages+0x176/0x180\n   vmemmap_populate+0x34/0x80\n   __populate_section_memmap+0x41/0x90\n   sparse_add_section+0x121/0x3e0\n   __add_pages+0xba/0x150\n   add_pages+0x1d/0x70\n   memremap_pages+0x3dc/0x810\n   devm_memremap_pages+0x1c/0x60\n   xe_devm_add+0x8b/0x100 [xe]\n   xe_tile_init_noalloc+0x6a/0x70 [xe]\n   xe_device_probe+0x48c/0x740 [xe]\n   [... snip ...]","modified":"2026-04-02T12:48:10.905119Z","published":"2025-09-19T15:26:19.225Z","related":["SUSE-SU-2025:03600-1","SUSE-SU-2025:03634-1","SUSE-SU-2025:20851-1","SUSE-SU-2025:20861-1","SUSE-SU-2025:20870-1","SUSE-SU-2025:20898-1","SUSE-SU-2025:21074-1","SUSE-SU-2025:21139-1","SUSE-SU-2025:21179-1","SUSE-SU-2025:3751-1","SUSE-SU-2025:4057-1","SUSE-SU-2025:4132-1","SUSE-SU-2025:4141-1","openSUSE-SU-2025:20081-1"],"database_specific":{"osv_generated_from":"https://github.com/CVEProject/cvelistV5/tree/main/cves/2025/39xxx/CVE-2025-39845.json","cna_assigner":"Linux"},"references":[{"type":"WEB","url":"https://git.kernel.org/stable/c/26ff568f390a531d1bd792e49f1a401849921960"},{"type":"WEB","url":"https://git.kernel.org/stable/c/5f761d40ee95d2624f839c90ebeef2d5c55007f5"},{"type":"WEB","url":"https://git.kernel.org/stable/c/6659d027998083fbb6d42a165b0c90dc2e8ba989"},{"type":"WEB","url":"https://git.kernel.org/stable/c/6bf9473727569e8283c1e2445c7ac42cf4fc9fa9"},{"type":"WEB","url":"https://git.kernel.org/stable/c/744ff519c72de31344a627eaf9b24e9595aae554"},{"type":"WEB","url":"https://git.kernel.org/stable/c/b7f4051dd3388edd30e9a6077c05c486aa31e0d4"},{"type":"WEB","url":"https://lists.debian.org/debian-lts-announce/2025/10/msg00008.html"},{"type":"ADVISORY","url":"https://github.com/CVEProject/cvelistV5/tree/main/cves/2025/39xxx/CVE-2025-39845.json"},{"type":"ADVISORY","url":"https://nvd.nist.gov/vuln/detail/CVE-2025-39845"},{"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":"8d400913c231bd1da74067255816453f96cd35b0"},{"fixed":"744ff519c72de31344a627eaf9b24e9595aae554"},{"fixed":"5f761d40ee95d2624f839c90ebeef2d5c55007f5"},{"fixed":"26ff568f390a531d1bd792e49f1a401849921960"},{"fixed":"b7f4051dd3388edd30e9a6077c05c486aa31e0d4"},{"fixed":"6bf9473727569e8283c1e2445c7ac42cf4fc9fa9"},{"fixed":"6659d027998083fbb6d42a165b0c90dc2e8ba989"}]}],"database_specific":{"source":"https://storage.googleapis.com/cve-osv-conversion/osv-output/CVE-2025-39845.json"}}],"schema_version":"1.7.5"}