mm/mremap.c | 4 +++-
 1 file changed, 3 insertions(+), 1 deletion(-)

diff --git a/mm/mremap.c b/mm/mremap.c
index 5dd572d57ca9..b3f073cf2806 100644
--- a/mm/mremap.c
+++ b/mm/mremap.c
@@ -208,8 +208,10 @@ static bool move_normal_pmd(struct vm_area_struct *vma, unsigned long old_addr,
 	 * The destination pmd shouldn't be established, free_pgtables()
 	 * should have release it.
 	 */
-	if (WARN_ON(!pmd_none(*new_pmd)))
+	if (WARN_ON(!pmd_none(*new_pmd))) {
+		printk(" old: %lx-%lx new: %lx (val: %lx)\n", old_addr, old_end, new_addr, pmd_val(*new_pmd));
 		return false;
+	}
 
 	/*
 	 * We don't have to worry about the ordering of src and dst