In the Linux kernel, the following vulnerability has been resolved: mm/damon/vaddr: avoid hw-driven pte updates during damon_hugetlb_mkold()… (CVE-2026-98505)

The vulnerability in the Linux kernel affects the damon_hugetlb_mkold() function within the mm/damon/vaddr subsystem. This function reads a page table entry (PTE), unsets the accessed bit, and writes back the updated PTE. However, if hardware concurrently updates the same PTE (e.g., setting dirty bits), those hardware updates can be lost due to a race condition. The fix involves using huge_ptep_get_and_clear() to atomically clear the PTE when reading it, ensuring that any concurrent hardware updates trigger a page fault and are properly serialized with the kernel's update. Because hugetlbfs is an in-memory filesystem and huge pages are not reclaimable, the impact is limited. The issue was discovered by Sashiko and has been fixed in the Linux kernel.

The vulnerability could cause loss of hardware-driven updates to page table entries, such as dirty bits, due to race conditions during concurrent updates by the kernel and hardware. However, since the affected subsystem deals with huge pages in an in-memory filesystem (hugetlbfs) where pages cannot be reclaimed, the impact is not considered critical or leading to system instability or data loss under normal conditions.

A fix is available in the Linux kernel that addresses the race condition by atomically clearing the page table entry during read operations using huge_ptep_get_and_clear(). Users should update to the fixed Linux kernel version containing this patch. No additional mitigation is indicated by the vendor advisory.