net/mlx5: Fix potential sleeping in atomic context

commit ee27e330a953595903979ffdb84926843595a9fe upstream.

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>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

diff --git a/drivers/net/ethernet/mellanox/mlx5/core/fs_core.c b/drivers/net/ethernet/mellanox/mlx5/core/fs_core.c
index 774f0a619a6da7a821e774b8f6021e2952f86efc..f0aa7f0e5480310611091b9797ee1dae344b269c 100644 (file)
--- a/drivers/net/ethernet/mellanox/mlx5/core/fs_core.c
+++ b/drivers/net/ethernet/mellanox/mlx5/core/fs_core.c
@@ -1558,9 +1558,9 @@ static int build_match_list(struct match_list_head *match_head,
 
                curr_match = kmalloc(sizeof(*curr_match), GFP_ATOMIC);
                if (!curr_match) {
+                       rcu_read_unlock();
                        free_match_list(match_head);
-                       err = -ENOMEM;
-                       goto out;
+                       return -ENOMEM;
                }
                if (!tree_get_node(&g->node)) {
                        kfree(curr_match);
@@ -1569,7 +1569,6 @@ static int build_match_list(struct match_list_head *match_head,
                curr_match->g = g;
                list_add_tail(&curr_match->list, &match_head->list);
        }
-out:
        rcu_read_unlock();
        return err;
 }