Index: dev/hwpmc/hwpmc_amd.c
===================================================================
--- dev/hwpmc/hwpmc_amd.c	(revision 233380)
+++ dev/hwpmc/hwpmc_amd.c	(working copy)
@@ -941,6 +941,7 @@
 		goto error;
 
 	/* Initialize AMD K7 and K8 PMC handling. */
+	printf("AMD CPU with classindex=%d\n", classindex);
 	pcd = &pmc_mdep->pmd_classdep[classindex];
 
 	pcd->pcd_caps		= AMD_PMC_CAPS;
Index: dev/hwpmc/hwpmc_mod.c
===================================================================
--- dev/hwpmc/hwpmc_mod.c	(revision 233380)
+++ dev/hwpmc/hwpmc_mod.c	(working copy)
@@ -4688,8 +4688,16 @@
 		    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 "
+				    "init function: class=%d, ri=%d\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 +4889,16 @@
 			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: class=%d, ri=%d\n",
+					    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);
 		}