[PATCH v2 3/3] mm/mincore: hold PTL in mincore_hugetlb

[Jinjiang Tu <tujinjiang@huawei.com>]

Hold PTL in mincore_hugetlb() to avoid operating on stale page, as
mincore_pte_range() have done.

Signed-off-by: Jinjiang Tu <tujinjiang@huawei.com>
---
 mm/mincore.c | 3 +++
 1 file changed, 3 insertions(+)

diff --git a/mm/mincore.c b/mm/mincore.c
index 42d6c9c8da86..10dabefc3acc 100644
--- a/mm/mincore.c
+++ b/mm/mincore.c
@@ -29,7 +29,9 @@ static int mincore_hugetlb(pte_t *pte, unsigned long hmask, unsigned long addr,
 #ifdef CONFIG_HUGETLB_PAGE
 	unsigned char present;
 	unsigned char *vec = walk->private;
+	spinlock_t *ptl;
 
+	ptl = huge_pte_lock(hstate_vma(walk->vma), walk->mm, pte);
 	/*
 	 * Hugepages under user process are always in RAM and never
 	 * swapped out, but theoretically it needs to be checked.
@@ -38,6 +40,7 @@ static int mincore_hugetlb(pte_t *pte, unsigned long hmask, unsigned long addr,
 	for (; addr != end; vec++, addr += PAGE_SIZE)
 		*vec = present;
 	walk->private = vec;
+	spin_unlock(ptl);
 #else
 	BUG();
 #endif
-- 
2.43.0