Index: dev/hwpmc/hwpmc_mod.c
===================================================================
--- dev/hwpmc/hwpmc_mod.c	(revision 233380)
+++ dev/hwpmc/hwpmc_mod.c	(working copy)
@@ -4688,8 +4688,13 @@
 		    M_WAITOK|M_ZERO);
 		if (md->pmd_pcpu_init)
 			error = md->pmd_pcpu_init(md, cpu);
-		for (n = 0; error == 0 && n < md->pmd_nclass; n++)
+		for (n = 0; error == 0 && n < md->pmd_nclass; n++) {
+			if (md->pmd_classdep[n].pcd_pcpu_init == NULL) {
+				printf("PMC class wtihous init function: class=%d, ri=%d\n",
+					md->pmd_classdep[n].pcd_class, md->pmd_classdep[n].pcd_ri);
+			}
 			error = md->pmd_classdep[n].pcd_pcpu_init(md, cpu);
+		}
 	}
 	pmc_restore_cpu_binding(&pb);