diff --git a/sys/dev/netmap/netmap_freebsd.c b/sys/dev/netmap/netmap_freebsd.c
index 2aecb53b47e4..fd4592b7b5ab 100644
--- a/sys/dev/netmap/netmap_freebsd.c
+++ b/sys/dev/netmap/netmap_freebsd.c
@@ -1024,7 +1024,7 @@ nm_os_kthread_wakeup_worker(struct nm_kthread *nmk)
 	mtx_lock(&nmk->worker_lock);
 	nmk->scheduled++;
 	if (nmk->worker_ctx.cfg.wchan) {
-		wakeup((void *)nmk->worker_ctx.cfg.wchan);
+		wakeup((void *)(uintptr_t)nmk->worker_ctx.cfg.wchan);
 	}
 	mtx_unlock(&nmk->worker_lock);
 }
@@ -1090,8 +1090,8 @@ nm_kthread_worker(void *data)
 				continue;
 			} else if (nmk->run) {
 				/* wait on event with one second timeout */
-				msleep_spin((void *)ctx->cfg.wchan, &nmk->worker_lock,
-					    "nmk_ev", hz);
+				msleep_spin((void *)(uintptr_t)ctx->cfg.wchan,
+				    &nmk->worker_lock, "nmk_ev", hz);
 				nmk->scheduled++;
 			}
 			mtx_unlock(&nmk->worker_lock);