CVE-2025-39845

*** Pendiente de traducción *** In the Linux kernel, the following vulnerability has been resolved:<br /> <br /> x86/mm/64: define ARCH_PAGE_TABLE_SYNC_MASK and arch_sync_kernel_mappings()<br /> <br /> Define ARCH_PAGE_TABLE_SYNC_MASK and arch_sync_kernel_mappings() to ensure<br /> page tables are properly synchronized when calling p*d_populate_kernel().<br /> <br /> For 5-level paging, synchronization is performed via<br /> pgd_populate_kernel(). In 4-level paging, pgd_populate() is a no-op, so<br /> synchronization is instead performed at the P4D level via<br /> p4d_populate_kernel().<br /> <br /> This fixes intermittent boot failures on systems using 4-level paging and<br /> a large amount of persistent memory:<br /> <br /> BUG: unable to handle page fault for address: ffffe70000000034<br /> #PF: supervisor write access in kernel mode<br /> #PF: error_code(0x0002) - not-present page<br /> PGD 0 P4D 0<br /> Oops: 0002 [#1] SMP NOPTI<br /> RIP: 0010:__init_single_page+0x9/0x6d<br /> Call Trace:<br /> <br /> __init_zone_device_page+0x17/0x5d<br /> memmap_init_zone_device+0x154/0x1bb<br /> pagemap_range+0x2e0/0x40f<br /> memremap_pages+0x10b/0x2f0<br /> devm_memremap_pages+0x1e/0x60<br /> dev_dax_probe+0xce/0x2ec [device_dax]<br /> dax_bus_probe+0x6d/0xc9<br /> [... snip ...]<br /> <br /> <br /> It also fixes a crash in vmemmap_set_pmd() caused by accessing vmemmap<br /> before sync_global_pgds() [1]:<br /> <br /> BUG: unable to handle page fault for address: ffffeb3ff1200000<br /> #PF: supervisor write access in kernel mode<br /> #PF: error_code(0x0002) - not-present page<br /> PGD 0 P4D 0<br /> Oops: Oops: 0002 [#1] PREEMPT SMP NOPTI<br /> Tainted: [W]=WARN<br /> RIP: 0010:vmemmap_set_pmd+0xff/0x230<br /> <br /> vmemmap_populate_hugepages+0x176/0x180<br /> vmemmap_populate+0x34/0x80<br /> __populate_section_memmap+0x41/0x90<br /> sparse_add_section+0x121/0x3e0<br /> __add_pages+0xba/0x150<br /> add_pages+0x1d/0x70<br /> memremap_pages+0x3dc/0x810<br /> devm_memremap_pages+0x1c/0x60<br /> xe_devm_add+0x8b/0x100 [xe]<br /> xe_tile_init_noalloc+0x6a/0x70 [xe]<br /> xe_device_probe+0x48c/0x740 [xe]<br /> [... snip ...]