diff --git a/lib/libthr/thread/thr_attr.c b/lib/libthr/thread/thr_attr.c
--- a/lib/libthr/thread/thr_attr.c
+++ b/lib/libthr/thread/thr_attr.c
@@ -597,11 +597,12 @@
 
 	if (kern_cpuset_size == 0) {
 		size_t len;
+		int maxid;
 
-		len = sizeof(kern_cpuset_size);
-		if (sysctlbyname("kern.sched.cpusetsize", &kern_cpuset_size,
-		    &len, NULL, 0))
-			PANIC("failed to get sysctl kern.sched.cpusetsize");
+		len = sizeof(maxid);
+		if (sysctlbyname("kern.smp.maxid", &maxid, &len, NULL, 0))
+			PANIC("failed to get sysctl kern.smp.maxid");
+		kern_cpuset_size = howmany(maxid, NBBY);
 	}
 
 	return (kern_cpuset_size);
diff --git a/share/man/man3/pthread_attr_affinity_np.3 b/share/man/man3/pthread_attr_affinity_np.3
--- a/share/man/man3/pthread_attr_affinity_np.3
+++ b/share/man/man3/pthread_attr_affinity_np.3
@@ -52,16 +52,16 @@
 .Dv CPU_SET
 macros.
 If the user-supplied mask is not large enough to fit all of the matching CPUs,
-.Fn cpuset_getaffinity
+.Fn pthread_attr_getaffinity_np
 fails with
 .Er ERANGE .
 Calls to
-.Fn cpuset_setaffinity
+.Fn pthread_attr_setaffinity_np
 tolerate masks of any size with no restrictions.
 The kernel uses the meaningful part of the mask, where the upper bound is
 the maximum CPU id present in the system.
 If bits for non-existing CPUs are set, calls to
-.Fn cpuset_setaffinity
+.Fn pthread_attr_setaffinity_np
 fails with
 .Er EINVAL .
 .Pp