Fixes: Commit cdbf9267 ("mm: numa: avoid waiting on freed migrated pages")

BugLink: https://bugs.launchpad.net/bugs/1797563

Commit cdbf9267 ("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 82b0f8c3
("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>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Signed-off-by: Stefan Bader <stefan.bader@canonical.com>
Signed-off-by: Kleber Sacilotto de Souza <kleber.souza@canonical.com>

mm/huge_memory.c

@@ -1393,12 +1393,12 @@ 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;
 	}