diff --git a/drivers/infiniband/hw/hfi1/user_exp_rcv.c b/drivers/infiniband/hw/hfi1/user_exp_rcv.c
index 4e986ca4dd35..6ebc984e1c1e 100644
--- a/drivers/infiniband/hw/hfi1/user_exp_rcv.c
+++ b/drivers/infiniband/hw/hfi1/user_exp_rcv.c
@@ -165,10 +165,12 @@ void hfi1_user_exp_rcv_free(struct hfi1_filedata *fd)
 	if (fd->handler) {
 		hfi1_mmu_rb_unregister(fd->handler);
 	} else {
+		mutex_lock(&uctxt->exp_mutex);
 		if (!EXP_TID_SET_EMPTY(uctxt->tid_full_list))
 			unlock_exp_tids(uctxt, &uctxt->tid_full_list, fd);
 		if (!EXP_TID_SET_EMPTY(uctxt->tid_used_list))
 			unlock_exp_tids(uctxt, &uctxt->tid_used_list, fd);
+		mutex_unlock(&uctxt->exp_mutex);
 	}
 
 	kfree(fd->invalid_tids);