[PATCH] thp: fix MADV_DONTNEED vs. MADV_FREE race

[Kirill A. Shutemov]

Basically the same race as with numa balancing in change_huge_pmd(), but
a bit simpler to mitigate: we don't need to preserve dirty/young flags
here due to MADV_FREE functionality.

Signed-off-by: Kirill A. Shutemov <kirill.shutemov@xxxxxxxxxxxxxxx>
Cc: Minchan Kim <minchan@xxxxxxxxxx>
---
 mm/huge_memory.c | 3 +--
 1 file changed, 1 insertion(+), 2 deletions(-)

diff --git a/mm/huge_memory.c b/mm/huge_memory.c
index bb2b3646bd78..23c1b3d58cf4 100644
--- a/mm/huge_memory.c
+++ b/mm/huge_memory.c
@@ -1566,8 +1566,7 @@ bool madvise_free_huge_pmd(struct mmu_gather *tlb, struct vm_area_struct *vma,
 		deactivate_page(page);
 
 	if (pmd_young(orig_pmd) || pmd_dirty(orig_pmd)) {
-		orig_pmd = pmdp_huge_get_and_clear_full(tlb->mm, addr, pmd,
-			tlb->fullmm);
+		pmdp_invalidate(vma, addr, pmd);
 		orig_pmd = pmd_mkold(orig_pmd);
 		orig_pmd = pmd_mkclean(orig_pmd);
 
-- 
 Kirill A. Shutemov