Commit e68a11a4 authored Sep 01, 2021 by Maor Gottlieb Committed by Greg Kroah-Hartman Sep 22, 2021

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: 693c6883 ("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>

parent 44428199

drivers/net/ethernet/mellanox/mlx5/core/fs_core.c

+2 −3

Original line number	Diff line number	Diff line
		@@ -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;
		}