Fix for Loss of Young/Dirty Bits During Pagemap Scan

CVE-2024-36943

What is CVE-2024-36943?

A memory management vulnerability in the Linux kernel affects the handling of page table entries (PTEs) during pagemap scans. The issue arises when multiple threads access or modify the same PTE, leading to potential loss of young and dirty bits, which are crucial for tracking memory state. The implementation of make_uffd_wp_pte() did not adequately protect against concurrent modifications, risking system stability and data integrity. Recent patches have addressed this by ensuring atomic operations during PTE updates, thereby preventing race conditions and ensuring accurate memory state representation.

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