CVE-2026-72043CVE-2026-72043

In the Linux kernel, the following vulnerability has been resolved: LoongArch: Fix missing dirty page tracking in {pte,pmd}_wrprotect() When hardware page table walker (PTW) is enabled on LoongArch, the CPU may set _PAGE_DIRTY directly in the page table entry during a write TLB miss, without going through the software TLB store handler. The software TLB store handler (tlbex.S:254) sets both _PAGE_DIRTY and_PAGE_MODIFIED together: ori t0, t0, (_PAGE_VALID | _PAGE_DIRTY | _PAGE_MODIFIED) Since hardware PTW only sets _PAGE_DIRTY, the software-only bit, i.e. _PAGE_MODIFIED is left unchanged. This creates a window where a PTE has _PAGE_DIRTY set (hardware knows the page is dirty) but _PAGE_MODIFIED clear (software is unaware). When fork()/clone() triggers copy-on-write, __copy_present_ptes() calls pte_wrprotect(), which unconditionally clears both the _PAGE_WRITE and _PAGE_DIRTY bits: pte_val(pte) &= ~(_PAGE_WRITE | _PAGE_DIRTY); Since _PAGE_MODIFIED was never set, the dirtin