In the Linux kernel, the following vulnerability has been resolved:

fs/proc/task_mmu: fix loss of young/dirty bits during pagemap scan

make_uffd_wp_pte() was previously doing:

  pte = ptep_get(ptep);
  ptep_modify_prot_start(ptep);
  pte = pte_mkuffd_wp(pte);
  ptep_modify_prot_commit(ptep, pte);

But if another thread accessed or dirtied the pte between the first 2
calls, this could lead to loss of that information.  Since
ptep_modify_prot_start() gets and clears atomically, the following is the
correct pattern and prevents any possible race.  Any access after the
first call would see an invalid pte and cause a fault:

  pte = ptep_modify_prot_start(ptep);
  pte = pte_mkuffd_wp(pte);
  ptep_modify_prot_commit(ptep, pte);

References:
http://web.nvd.nist.gov/view/vuln/detail?vulnId=CVE-2024-36943
https://git.kernel.org/pub/scm/linux/security/vulns.git/plain/cve/published/2024/CVE-2024-36943.mbox
https://git.kernel.org/stable/c/74b3d66f91d9f539f99faad74d796fa9a389a015
https://git.kernel.org/stable/c/c70dce4982ce1718bf978a35f8e26160b82081f4
https://www.cve.org/CVERecord?id=CVE-2024-36943
https://bugzilla.redhat.com/show_bug.cgi?id=2284470