1 files changed, 3 insertions, 1 deletions

diff --git a/lib/idr.c b/lib/idr.c
index 1cac726c44bc..0dc782216d4b 100644
--- a/lib/idr.c
+++ b/lib/idr.c
@@ -156,10 +156,12 @@ static int sub_alloc(struct idr *idp, int *starting_id, struct idr_layer **pa)
                         id = (id | ((1 << (IDR_BITS * l)) - 1)) + 1;
 
                         /* if already at the top layer, we need to grow */
-                        if (!(p = pa[l])) {
+                        if (id >= 1 << (idp->layers * IDR_BITS)) {
                                 *starting_id = id;
                                 return IDR_NEED_TO_GROW;
                         }
+                        p = pa[l];
+                        BUG_ON(!p);
 
                         /* If we need to go up one layer, continue the
                          * loop; otherwise, restart from the top.