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-rw-r--r--mm/hugetlb.c14
1 files changed, 12 insertions, 2 deletions
diff --git a/mm/hugetlb.c b/mm/hugetlb.c
index 07abcb6eb203..245038a9fe4e 100644
--- a/mm/hugetlb.c
+++ b/mm/hugetlb.c
@@ -5478,7 +5478,7 @@ static vm_fault_t hugetlb_wp(struct mm_struct *mm, struct vm_area_struct *vma,
struct folio *pagecache_folio, spinlock_t *ptl)
{
const bool unshare = flags & FAULT_FLAG_UNSHARE;
- pte_t pte;
+ pte_t pte = huge_ptep_get(ptep);
struct hstate *h = hstate_vma(vma);
struct page *old_page;
struct folio *new_folio;
@@ -5488,6 +5488,17 @@ static vm_fault_t hugetlb_wp(struct mm_struct *mm, struct vm_area_struct *vma,
struct mmu_notifier_range range;
/*
+ * Never handle CoW for uffd-wp protected pages. It should be only
+ * handled when the uffd-wp protection is removed.
+ *
+ * Note that only the CoW optimization path (in hugetlb_no_page())
+ * can trigger this, because hugetlb_fault() will always resolve
+ * uffd-wp bit first.
+ */
+ if (!unshare && huge_pte_uffd_wp(pte))
+ return 0;
+
+ /*
* hugetlb does not support FOLL_FORCE-style write faults that keep the
* PTE mapped R/O such as maybe_mkwrite() would do.
*/
@@ -5500,7 +5511,6 @@ static vm_fault_t hugetlb_wp(struct mm_struct *mm, struct vm_area_struct *vma,
return 0;
}
- pte = huge_ptep_get(ptep);
old_page = pte_page(pte);
delayacct_wpcopy_start();