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Description

In the Linux kernel, the following vulnerability has been resolved: mm/userfaultfd: fix hugetlb fault mutex hash calculation In mfill_atomic_hugetlb(), linear_page_index() is used to calculate the page index for hugetlb_fault_mutex_hash(). However, linear_page_index() returns the index in PAGE_SIZE units, while hugetlb_fault_mutex_hash() expects the index in huge page units. This mismatch means that different addresses within the same huge page can produce different hash values, leading to the use of different mutexes for the same huge page. This can cause races between faulting threads, which can corrupt the reservation map and trigger the BUG_ON in resv_map_release(). Fix this by introducing hugetlb_linear_page_index(), which returns the page index in huge page granularity, and using it in place of linear_page_index().

PUBLISHED Reserved 2026-03-09 | Published 2026-04-24 | Updated 2026-05-11 | Assigner Linux

Product status

Default status
unaffected

a08c7193e4f18dc8508f2d07d0de2c5b94cb39a3 (git) before 5a525c43baaba0bf3063f86996ca3623b71e4172
affected

a08c7193e4f18dc8508f2d07d0de2c5b94cb39a3 (git) before 574501ede47ac439afd67ba9812bc66722d500ba
affected

a08c7193e4f18dc8508f2d07d0de2c5b94cb39a3 (git) before 08282b1bf74c69fc8ecd25493e7fdb5460f01290
affected

a08c7193e4f18dc8508f2d07d0de2c5b94cb39a3 (git) before f4689fc089765d36c026063fb22d23533e883eb6
affected

a08c7193e4f18dc8508f2d07d0de2c5b94cb39a3 (git) before 0217c7fb4de4a40cee667eb21901f3204effe5ac
affected

Default status
affected

6.7
affected

Any version before 6.7
unaffected

6.12.84 (semver)
unaffected

6.18.24 (semver)
unaffected

6.19.14 (semver)
unaffected

7.0.1 (semver)
unaffected

7.1-rc1 (original_commit_for_fix)
unaffected

References

git.kernel.org/...c/5a525c43baaba0bf3063f86996ca3623b71e4172

git.kernel.org/...c/574501ede47ac439afd67ba9812bc66722d500ba

git.kernel.org/...c/08282b1bf74c69fc8ecd25493e7fdb5460f01290

git.kernel.org/...c/f4689fc089765d36c026063fb22d23533e883eb6

git.kernel.org/...c/0217c7fb4de4a40cee667eb21901f3204effe5ac

cve.org (CVE-2026-31575)

nvd.nist.gov (CVE-2026-31575)

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