1 files changed, 6 insertions, 3 deletions

diff --git a/lib/idr.c b/lib/idr.c
index ba7d37cf7847..0dc782216d4b 100644
--- a/lib/idr.c
+++ b/lib/idr.c
@@ -140,7 +140,8 @@ static int sub_alloc(struct idr *idp, int *starting_id, struct idr_layer **pa)
         id = *starting_id;
  restart:
         p = idp->top;
-        l = p->layer;
+        l = idp->layers;
+        pa[l--] = NULL;
         while (1) {
                 /*
                  * We run around this while until we reach the leaf node...
@@ -154,11 +155,13 @@ static int sub_alloc(struct idr *idp, int *starting_id, struct idr_layer **pa)
                         oid = id;
                         id = (id | ((1 << (IDR_BITS * l)) - 1)) + 1;
 
-                        /* did id go over the limit? */
-                        if (id >= (1 << (idp->layers * IDR_BITS))) {
+                        /* if already at the top layer, we need to grow */
+                        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.