Index: uspace/srv/bd/hr/util.c
===================================================================
--- uspace/srv/bd/hr/util.c	(revision 723f1d98e99f4824a68ba99c63a1f32280726650)
+++ uspace/srv/bd/hr/util.c	(revision 7a3529a8736f62cf391c3de6400272e1324a36fc)
@@ -213,4 +213,6 @@
 void hr_update_ext_status(hr_volume_t *vol, size_t extent, hr_ext_status_t s)
 {
+	assert(extent < vol->extent_no);
+
 	hr_ext_status_t old = vol->extents[extent].status;
 	HR_WARN("\"%s\": changing extent %lu state: %s -> %s\n",
@@ -222,4 +224,6 @@
 void hr_update_hotspare_status(hr_volume_t *vol, size_t hs, hr_ext_status_t s)
 {
+	assert(hs < vol->hotspare_no);
+
 	hr_ext_status_t old = vol->hotspares[hs].status;
 	HR_WARN("\"%s\": changing hotspare %lu state: %s -> %s\n",