diff --git a/drivers/infiniband/hw/mlx5/mlx5_ib.h b/drivers/infiniband/hw/mlx5/mlx5_ib.h
index dcdcd195fe53a4dd003b0d22426d146bb81c0380..7d689903c87cfea2a84755f81362095c97167c8d 100644
--- a/drivers/infiniband/hw/mlx5/mlx5_ib.h
+++ b/drivers/infiniband/hw/mlx5/mlx5_ib.h
@@ -626,6 +626,8 @@ struct mlx5_ib_dev {
 	struct mlx5_ib_resources	devr;
 	struct mlx5_mr_cache		cache;
 	struct timer_list		delay_timer;
+	/* Prevents soft lock on massive reg MRs */
+	struct mutex			slow_path_mutex;
 	int				fill_delay;
 #ifdef CONFIG_INFINIBAND_ON_DEMAND_PAGING
 	struct ib_odp_caps	odp_caps;
diff --git a/drivers/infiniband/hw/mlx5/mr.c b/drivers/infiniband/hw/mlx5/mr.c
index d4ad672b905bf0068b59b2ebffe8de8a85f035e1..4e9012463c37de6381cddde1c527e4c2ff6e84ae 100644
--- a/drivers/infiniband/hw/mlx5/mr.c
+++ b/drivers/infiniband/hw/mlx5/mr.c
@@ -610,6 +610,7 @@ int mlx5_mr_cache_init(struct mlx5_ib_dev *dev)
 	int err;
 	int i;
 
+	mutex_init(&dev->slow_path_mutex);
 	cache->wq = alloc_ordered_workqueue("mkey_cache", WQ_MEM_RECLAIM);
 	if (!cache->wq) {
 		mlx5_ib_warn(dev, "failed to create work queue\n");
@@ -1182,9 +1183,12 @@ struct ib_mr *mlx5_ib_reg_user_mr(struct ib_pd *pd, u64 start, u64 length,
 		goto error;
 	}
 
-	if (!mr)
+	if (!mr) {
+		mutex_lock(&dev->slow_path_mutex);
 		mr = reg_create(NULL, pd, virt_addr, length, umem, ncont,
 				page_shift, access_flags);
+		mutex_unlock(&dev->slow_path_mutex);
+	}
 
 	if (IS_ERR(mr)) {
 		err = PTR_ERR(mr);