Description
In the Linux kernel, the following vulnerability has been resolved: riscv: mm: Fix out-of-bounds page-table walk during memory hot-remove remove_pud_mapping() and remove_p4d_mapping() obtain a child table base with pud_offset(p4dp, 0) and p4d_offset(pgd, 0), then add the index for addr. RISC-V folds page-table levels at runtime. When a level is folded, its offset helper returns the parent entry itself, but the index can still be nonzero. Adding it walks past the parent table. Sv48 folds P4D, while Sv39 folds both P4D and PUD, so memory hot-remove can descend into unrelated memory and pass an invalid page to __free_pages(). This can trigger: kernel BUG at include/linux/mm.h:1810! VM_BUG_ON_PAGE(page_ref_count(page) == 0) arch_remove_memory+0x1e/0x5c try_remove_memory+0x15e/0x200 remove_memory+0x24/0x3c Only add the index when the corresponding page-table level is enabled, matching p4d_offset() and pud_offset().
Affected products
Version statuses are supplied by the assigning organization. Consult the original record for detailed ranges and platform conditions.
Linux Linux
Default version status: unaffected
c75a74f4ba19c904c0ae1e011ae2568449409ae4 to < 1da6d832eda02d908df11a30ba6a856b98a3dd76affectedc75a74f4ba19c904c0ae1e011ae2568449409ae4 to < 54e07a158f7aea2754849d3a5a4cba1ac338ae7eaffectedc75a74f4ba19c904c0ae1e011ae2568449409ae4 to < 1bb0ef8069ef158d245bac91ac178bb4f1a7ccd2affectedc75a74f4ba19c904c0ae1e011ae2568449409ae4 to < a0188cc133696627857d16054e43f9ebc7efc821affected
Linux Linux
Default version status: affected
6.11affected0 to < 6.11unaffected6.12.103 to ≤ 6.12.*unaffected6.18.44 to ≤ 6.18.*unaffected7.1.8 to ≤ 7.1.*unaffected7.2 to ≤ *unaffected