diff --git a/lib/nvmf/ctrlr.c b/lib/nvmf/ctrlr.c
index 0761fa421..1dfcb4a4c 100644
--- a/lib/nvmf/ctrlr.c
+++ b/lib/nvmf/ctrlr.c
@@ -3409,6 +3409,8 @@ _nvmf_request_complete(void *ctx)
 		    sgroup->io_outstanding == 0) {
 			sgroup->state = SPDK_NVMF_SUBSYSTEM_PAUSED;
 			sgroup->cb_fn(sgroup->cb_arg, 0);
+			sgroup->cb_fn = NULL;
+			sgroup->cb_arg = NULL;
 		}
 	}
 
diff --git a/lib/nvmf/nvmf.c b/lib/nvmf/nvmf.c
index 5ea319caf..0f473eed9 100644
--- a/lib/nvmf/nvmf.c
+++ b/lib/nvmf/nvmf.c
@@ -1424,7 +1424,9 @@ nvmf_poll_group_pause_subsystem(struct spdk_nvmf_poll_group *group,
 	sgroup->state = SPDK_NVMF_SUBSYSTEM_PAUSING;
 
 	if (sgroup->io_outstanding > 0) {
+		assert(sgroup->cb_fn == NULL);
 		sgroup->cb_fn = cb_fn;
+		assert(sgroup->cb_arg == NULL);
 		sgroup->cb_arg = cb_arg;
 		return;
 	}