diff --git a/lib/libzpool/include/sys/zfs_context.h b/lib/libzpool/include/sys/zfs_context.h
index f924dd1a64..0e7019bba8 100644
--- a/lib/libzpool/include/sys/zfs_context.h
+++ b/lib/libzpool/include/sys/zfs_context.h
@@ -195,7 +195,7 @@ typedef struct kthread kthread_t;
 	zk_thread_create(func, arg)
 #define	thread_exit() thr_exit(NULL)
 
-extern kthread_t *zk_thread_create(void (*func)(void), void *arg);
+extern kthread_t *zk_thread_create(void (*func)(), void *arg);
 
 #define	issig(why)	(FALSE)
 #define	ISSIG(thr, why)	(FALSE)
diff --git a/lib/libzpool/kernel.c b/lib/libzpool/kernel.c
index 9740f1ba6e..fe817cc64b 100644
--- a/lib/libzpool/kernel.c
+++ b/lib/libzpool/kernel.c
@@ -56,7 +56,7 @@ struct utsname utsname = {
  */
 /*ARGSUSED*/
 kthread_t *
-zk_thread_create(void (*func)(void), void *arg)
+zk_thread_create(void (*func)(), void *arg)
 {
 	thread_t tid;