net/mlx5: Fix potential sleeping in atomic context

Fixes the below flow of sleeping in atomic context by releasing
the RCU lock before calling to free_match_list.

build_match_list() <- disables preempt
-> free_match_list()
   -> tree_put_node()
      -> down_write_ref_node() <- take write lock

Fixes: 693c6883bbc4 ("net/mlx5: Add hash table for flow groups in flow table")
Reported-by: Dan Carpenter <dan.carpenter@oracle.com>
Signed-off-by: Maor Gottlieb <maorg@nvidia.com>
Signed-off-by: Saeed Mahameed <saeedm@nvidia.com>

diff --git a/drivers/net/ethernet/mellanox/mlx5/core/fs_core.c b/drivers/net/ethernet/mellanox/mlx5/core/fs_core.c
index 9fe8e3c204d63a117a21c68f6cda37b463ba25fa..fe501ba88bea9cd11548851dab9eaf4e5503be98 100644 (file)
--- a/drivers/net/ethernet/mellanox/mlx5/core/fs_core.c
+++ b/drivers/net/ethernet/mellanox/mlx5/core/fs_core.c
@@ -1682,14 +1682,13 @@ static int build_match_list(struct match_list *match_head,
 
                curr_match = kmalloc(sizeof(*curr_match), GFP_ATOMIC);
                if (!curr_match) {
+                       rcu_read_unlock();
                        free_match_list(match_head, ft_locked);
-                       err = -ENOMEM;
-                       goto out;
+                       return -ENOMEM;
                }
                curr_match->g = g;
                list_add_tail(&curr_match->list, &match_head->list);
        }
-out:
        rcu_read_unlock();
        return err;
 }