diff --git a/tools/uma/smrstress/smrstress.c b/tools/uma/smrstress/smrstress.c
index 7e7ee4ea065c..2cf5f50ffae4 100644
--- a/tools/uma/smrstress/smrstress.c
+++ b/tools/uma/smrstress/smrstress.c
@@ -1,228 +1,229 @@
 /*-
  * SPDX-License-Identifier: BSD-2-Clause-FreeBSD
  *
  * Copyright (c) 2020 Jeffrey Roberson <jeff@FreeBSD.org>
  *
  * Redistribution and use in source and binary forms, with or without
  * modification, are permitted provided that the following conditions
  * are met:
  * 1. Redistributions of source code must retain the above copyright
  *    notice unmodified, this list of conditions, and the following
  *    disclaimer.
  * 2. Redistributions in binary form must reproduce the above copyright
  *    notice, this list of conditions and the following disclaimer in the
  *    documentation and/or other materials provided with the distribution.
  *
  * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
  * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
  * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
  * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
  * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
  * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
  * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
  * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
  * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
  * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
  *
  * $FreeBSD$
  *
  */
 #include <sys/param.h>
 #include <sys/systm.h>
 #include <sys/kernel.h>
 #include <sys/libkern.h>
 #include <sys/module.h>
 #include <sys/mutex.h>
 #include <sys/proc.h>
 #include <sys/kthread.h>
 #include <sys/conf.h>
 #include <sys/mbuf.h>
 #include <sys/smp.h>
 #include <sys/smr.h>
 
 #include <vm/uma.h>
 
 #include <machine/stdarg.h>
 
 static uma_zone_t smrs_zone;
 static smr_t smrs_smr;
 
 static int smrs_cpus;
 static int smrs_writers;
 static int smrs_started;
 static int smrs_iterations = 10000000;
 static int smrs_failures = 0;
 static volatile int smrs_completed;
 
 struct smrs {
 	int		generation;
 	volatile u_int	count;
 };
 
 uintptr_t smrs_current;
 
 static void
 smrs_error(struct smrs *smrs, const char *fmt, ...)
 {
 	va_list ap;
 
 	atomic_add_int(&smrs_failures, 1);
 	printf("SMR ERROR: wr_seq %d, rd_seq %d, c_seq %d, generation %d, count %d ",
 	    smrs_smr->c_shared->s_wr.seq, smrs_smr->c_shared->s_rd_seq,
 	    zpcpu_get(smrs_smr)->c_seq, smrs->generation, smrs->count);
 	va_start(ap, fmt);
 	(void)vprintf(fmt, ap);
 	va_end(ap);
 }
 
 static void
 smrs_read(void)
 {
 	struct smrs *cur;
 	int cnt;
 
 	/* Wait for the writer to exit. */
 	while (smrs_completed == 0) {
 		smr_enter(smrs_smr);
 		cur = (void *)atomic_load_acq_ptr(&smrs_current);
 		if (cur->generation == -1)
 			smrs_error(cur, "read early: Use after free!\n");
 		atomic_add_int(&cur->count, 1);
 		DELAY(100);
 		cnt = atomic_fetchadd_int(&cur->count, -1);
 		if (cur->generation == -1)
 			smrs_error(cur, "read late: Use after free!\n");
 		else if (cnt <= 0)
 			smrs_error(cur, "Invalid ref\n");
 		smr_exit(smrs_smr);
 		maybe_yield();
 	}
 }
 
 static void
 smrs_write(void)
 {
 	struct smrs *cur;
 	int i;
 
 	for (i = 0; i < smrs_iterations; i++) {
 		cur = uma_zalloc_smr(smrs_zone, M_WAITOK);
 		atomic_thread_fence_rel();
 		cur = (void *)atomic_swap_ptr(&smrs_current, (uintptr_t)cur);
 		uma_zfree_smr(smrs_zone, cur);
 	}
 }
 
 static void
 smrs_thread(void *arg)
 {
 	int rw = (intptr_t)arg;
 
 	if (rw < smrs_writers)
 		smrs_write();
 	else
 		smrs_read();
 	atomic_add_int(&smrs_completed, 1);
+	kthread_exit();
 }
 
 static void
 smrs_start(void)
 {
 	struct smrs *cur;
 	int i;
 
 	smrs_cpus = mp_ncpus;
 	if (mp_ncpus > 3)
 		smrs_writers = 2;
 	else
 		smrs_writers = 1;
 	smrs_started = smrs_cpus;
 	smrs_completed = 0;
 	atomic_store_rel_ptr(&smrs_current,
 	    (uintptr_t)uma_zalloc_smr(smrs_zone, M_WAITOK));
 	for (i = 0; i < smrs_started; i++)
 		kthread_add((void (*)(void *))smrs_thread,
 		    (void *)(intptr_t)i, curproc, NULL, 0, 0, "smrs-%d", i);
 
 	while (smrs_completed != smrs_started)
 		pause("prf", hz/2);
 
 	cur = (void *)smrs_current;
 	smrs_current = (uintptr_t)NULL;
 	uma_zfree_smr(smrs_zone, cur);
 
 	printf("Completed %d loops with %d failures\n",
 	    smrs_iterations, smrs_failures);
 }
 
 static int
 smrs_ctor(void *mem, int size, void *arg, int flags)
 {
 	static int smr_generation = 0;
 	struct smrs *smrs = mem;
 
 	if (smrs->generation != -1 && smrs->generation != 0)
 		smrs_error(smrs, "ctor: Invalid smr generation on ctor\n");
 	else if (smrs->count != 0)
 		smrs_error(smrs, "ctor: Invalid count\n");
 	smrs->generation = ++smr_generation;
 
 	return (0);
 }
 
 
 static void
 smrs_dtor(void *mem, int size, void *arg)
 {
 	struct smrs *smrs = mem;
 
 	if (smrs->generation == -1)
 		smrs_error(smrs, "dtor: Invalid generation");
 	smrs->generation = -1;
 	if (smrs->count != 0)
 		smrs_error(smrs, "dtor: Invalid count\n");
 }
 
 
 static void
 smrs_init(void)
 {
 
 	smrs_zone = uma_zcreate("smrs", sizeof(struct smrs),
 	    smrs_ctor,  smrs_dtor, NULL, NULL, UMA_ALIGN_PTR,
 	    UMA_ZONE_SMR | UMA_ZONE_ZINIT);
         smrs_smr = uma_zone_get_smr(smrs_zone);
 }
 
 static void
 smrs_fini(void)
 {
 
 	uma_zdestroy(smrs_zone);
 }
 
 static int
 smrs_modevent(module_t mod, int what, void *arg)
 {
 
 	switch (what) {
 	case MOD_LOAD:
 		smrs_init();
 		smrs_start();
 		break;
 	case MOD_UNLOAD:
 		smrs_fini();
 		break;
 	default:
 		break;
 	}
 	return (0);
 }
 
 moduledata_t smrs_meta = {
 	"smrstress",
 	smrs_modevent,
 	NULL
 };
 DECLARE_MODULE(smrstress, smrs_meta, SI_SUB_DRIVERS, SI_ORDER_MIDDLE);
 MODULE_VERSION(smrstress, 1);