mm: fix vma->anon_name memory leak for anonymous shmem VMAs

free_anon_vma_name() is missing a check for anonymous shmem VMA which
leads to a memory leak due to refcount not being dropped.  Fix this by
calling anon_vma_name_put() unconditionally.  It will free vma->anon_name
whenever it's non-NULL.

Link: https://lkml.kernel.org/r/[email protected]
Fixes: d09e8ca ("mm: anonymous shared memory naming")
Signed-off-by: Suren Baghdasaryan <[email protected]>
Suggested-by: David Hildenbrand <[email protected]>
Reviewed-by: David Hildenbrand <[email protected]>
Reported-by: [email protected]
Cc: Hugh Dickins <[email protected]>
Cc: Pasha Tatashin <[email protected]>
Signed-off-by: Andrew Morton <[email protected]>

Author: surenbaghdasaryan

include/linux/mm_inline.h

@@ -413,8 +413,7 @@ static inline void free_anon_vma_name(struct vm_area_struct *vma)
 	 * Not using anon_vma_name because it generates a warning if mmap_lock
 	 * is not held, which might be the case here.
 	 */
-	if (!vma->vm_file)
-		anon_vma_name_put(vma->anon_name);
+	anon_vma_name_put(vma->anon_name);
 }
 
 static inline bool anon_vma_name_eq(struct anon_vma_name *anon_name1,