In the Linux kernel, the following vulnerability has been resolved: mm/hugetlb: preserve mremap address delta when skipping page tables move_hugetlb_page_tables() optimizes mremap() by advancing to the last entry in the page table when the source page table does not exist, either initially or after unsharing a PMD table. The common loop increment then steps to the first entry in the next page table. However, the code advances both the source and destination addresses to the last entries in their respective page tables, which is wrong. The destination address must be advanced only by the same amount as the source address. If the source and destination offsets within their page tables differ, the destination address can be advanced too far, causing follow-up issues. Fix this by advancing the destination address by the source advance distance. With a reproducer, we were able to trigger a kernel panic on x86-64. With this fix in place, we can no longer reproduce the issue.
https://git.kernel.org/stable/c/9bdad082d44bdcf93716973dcba6be77e8a06e7b
https://git.kernel.org/stable/c/850cc4a84b36a0062dcd0391acd2450e20ab0767
https://git.kernel.org/stable/c/7a96b0f657c8d799ea5b8e02fc9ec7cca0e6e7ff
https://git.kernel.org/stable/c/480a39b0a12c977ed6e755f3d12a23424c57d11f