[PATCH][v3.18.y] Fixes: Commit 86af955d02bb ("mm: numa: avoid waiting on freed migrated pages")

[Chas Williams <3chas3@gmail.com>]

From: Chas Williams <chas3@att.com>

Commit 86af955d02bb ("mm: numa: avoid waiting on freed migrated pages")
was an incomplete backport of the upstream commit.  It is necessary to
always reset page_nid before attempting any early exit.

The original commit conflicted due to lack of commit 82b0f8c39a38
("mm: join struct fault_env and vm_fault") in 4.9 so it wasn't a clean
application, and the change must have just gotten lost in the noise.

Signed-off-by: Chas Williams <chas3@att.com>
---
 mm/huge_memory.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/mm/huge_memory.c b/mm/huge_memory.c
index 690d172436c4..bc402f39ac48 100644
--- a/mm/huge_memory.c
+++ b/mm/huge_memory.c
@@ -1329,12 +1329,12 @@ int do_huge_pmd_numa_page(struct mm_struct *mm, struct vm_area_struct *vma,
 
 	/* Migration could have started since the pmd_trans_migrating check */
 	if (!page_locked) {
+		page_nid = -1;
 		if (!get_page_unless_zero(page))
 			goto out_unlock;
 		spin_unlock(ptl);
 		wait_on_page_locked(page);
 		put_page(page);
-		page_nid = -1;
 		goto out;
 	}
 
-- 
2.14.4