Index: dev/hwpmc/hwpmc_mod.c
===================================================================
--- dev/hwpmc/hwpmc_mod.c	(revision 233380)
+++ dev/hwpmc/hwpmc_mod.c	(working copy)
@@ -4688,8 +4688,17 @@
 		    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++)
-			error = md->pmd_classdep[n].pcd_pcpu_init(md, cpu);
+		for (n = 0; error == 0 && n < md->pmd_nclass; n++) {
+			if (md->pmd_classdep[n].pcd_pcpu_init == NULL) {
+				printf(
+				    "hwpmc: PMC classdep without fini "
+				    "function: idx=%d pcd_class=%d pcd_ri=%d\n",
+				    n, md->pmd_classdep[n].pcd_class,
+				    md->pmd_classdep[n].pcd_ri);
+			}
+			else
+				error = md->pmd_classdep[n].pcd_pcpu_init(md, cpu);
+		}
 	}
 	pmc_restore_cpu_binding(&pb);
 
@@ -4881,8 +4890,17 @@
 			if (!pmc_cpu_is_active(cpu) || pmc_pcpu[cpu] == NULL)
 				continue;
 			pmc_select_cpu(cpu);
-			for (c = 0; c < md->pmd_nclass; c++)
-				md->pmd_classdep[c].pcd_pcpu_fini(md, cpu);
+			for (c = 0; c < md->pmd_nclass; c++) {
+				if (md->pmd_classdep[c].pcd_pcpu_fini == NULL) {
+					printf(
+					    "hwpmc: PMC classdep without init "
+					    "function: idx=%d pcd_class=%d pcd_ri=%d\n",
+					    c, md->pmd_classdep[c].pcd_class,
+					    md->pmd_classdep[c].pcd_ri);
+				}
+				else
+					md->pmd_classdep[c].pcd_pcpu_fini(md, cpu);
+			}
 			if (md->pmd_pcpu_fini)
 				md->pmd_pcpu_fini(md, cpu);
 		}
Index: dev/hwpmc/hwpmc_intel.c
===================================================================
--- dev/hwpmc/hwpmc_intel.c	(revision 233380)
+++ dev/hwpmc/hwpmc_intel.c	(working copy)
@@ -239,6 +239,10 @@
 		KASSERT(0, ("[intel,%d] Unknown CPU type", __LINE__));
 	}
 
+
+	if (error)
+		goto error;
+
 	/*
 	 * Init the uncore class.
 	 */
Index: dev/hwpmc/hwpmc_core.c
===================================================================
--- dev/hwpmc/hwpmc_core.c	(revision 233380)
+++ dev/hwpmc/hwpmc_core.c	(working copy)
@@ -2406,8 +2406,12 @@
 	PMCDBG(MDP,INI,1,"core-init cputype=%d ncpu=%d ipa-version=%d",
 	    md->pmd_cputype, maxcpu, ipa_version);
 
-	if (ipa_version < 1 || ipa_version > 3)	/* Unknown PMC architecture. */
+	if (ipa_version < 1 || ipa_version > 3) {
+		/* Unknown PMC architecture. */
+		printf("hwpc_core: unknown PMC architecture: %d\n",
+		    ipa_version);
 		return (EPROGMISMATCH);
+	}
 
 	core_cputype = md->pmd_cputype;