Missed calling flush_cache_range() before removing the sharing PMD entrires,
otherwise data consistence issue may be occurred on some architectures whose
caches are strict and require a virtual–>physical translation to exist for
a virtual address. Thus add it.
Now no architectures enabling PMD sharing will be affected, since they do
not have a VIVT cache. That means this issue can not be happened in practice
so far.
Fixes: 6dfeaff93be1 ("hugetlb/userfaultfd: unshare all pmds for hugetlbfs when register wp")
Signed-off-by: Baolin Wang <baolin.wang@xxxxxxxxxxxxxxxxx>
Reviewed-by: Muchun Song <songmuchun@xxxxxxxxxxxxx>
---
Changes from v1:
- Add more comments in commit message suggested by Muchun.
- Add reviewed-by tag from Muchun.
---
mm/hugetlb.c | 1 +
1 file changed, 1 insertion(+)
diff --git a/mm/hugetlb.c b/mm/hugetlb.c
index 74c9964..1945dfb 100644
--- a/mm/hugetlb.c
+++ b/mm/hugetlb.c
@@ -7058,6 +7058,7 @@ void hugetlb_unshare_all_pmds(struct vm_area_struct *vma)
if (start >= end)
return;
+ flush_cache_range(vma, start, end);
/*
* No need to call adjust_range_if_pmd_sharing_possible(), because
* we have already done the PUD_SIZE alignment.
--
1.8.3.1
