mm: fix error reporting in move_pages() syscall

The vma returned by find_vma does not necessarily include the target
address.  If this happens the code tries to follow a page outside of any
vma and returns ENOENT instead of EFAULT.
Signed-off-by: NGleb Natapov <gleb@redhat.com>
Acked-by: NChristoph Lameter <cl@linux-foundation.org>
Cc: Minchan Kim <minchan.kim@gmail.com>
Cc: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>
Cc: Mel Gorman <mel@csn.ul.ie>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

mm/migrate.c

@@ -1037,7 +1037,7 @@ static int do_move_page_to_node_array(struct mm_struct *mm,
 
 		err = -EFAULT;
 		vma = find_vma(mm, pp->addr);
-		if (!vma || !vma_migratable(vma))
+		if (!vma || pp->addr < vma->vm_start || !vma_migratable(vma))
 			goto set_status;
 
 		page = follow_page(vma, pp->addr, FOLL_GET);
@@ -1204,7 +1204,7 @@ static void do_pages_stat_array(struct mm_struct *mm, unsigned long nr_pages,
 		int err = -EFAULT;
 
 		vma = find_vma(mm, addr);
-		if (!vma)
+		if (!vma || addr < vma->vm_start)
 			goto set_status;
 
 		page = follow_page(vma, addr, 0);