From fd3307130344ef5fa5af0089d343ca4fc074322e Mon Sep 17 00:00:00 2001 From: Vlad Buslov Date: Wed, 26 Sep 2018 13:09:44 +0300 Subject: net/mlx5: Take fs_counters dellist before addlist In fs_counters elements from both addlist and dellist are removed by mlx5_fc_stats_work() without any locking. This introduces race condition when batch of new rules is created and then immediately deleted (for example, when error occurred during flow creation). In such case some of the rules might be in dellist, but not in addlist when mlx5_fc_stats_work() is executed concurrently with tc, which will result rule deletion and use-after-free on next iteration because deleted rules are still in addlist. Always take dellist first to guarantee that rules can only be deleted after they were removed from addlist. Fixes: 6e5e22839136 ("net/mlx5: Add new list to store deleted flow counters") Signed-off-by: Vlad Buslov Reported-by: Chris Mi Reviewed-by: Roi Dayan --- drivers/net/ethernet/mellanox/mlx5/core/fs_counters.c | 13 ++++++++----- 1 file changed, 8 insertions(+), 5 deletions(-) (limited to 'drivers/net/ethernet/mellanox/mlx5') diff --git a/drivers/net/ethernet/mellanox/mlx5/core/fs_counters.c b/drivers/net/ethernet/mellanox/mlx5/core/fs_counters.c index 1329bc5b7969..77bd4cd3a1db 100644 --- a/drivers/net/ethernet/mellanox/mlx5/core/fs_counters.c +++ b/drivers/net/ethernet/mellanox/mlx5/core/fs_counters.c @@ -179,19 +179,22 @@ static void mlx5_fc_stats_work(struct work_struct *work) struct mlx5_core_dev *dev = container_of(work, struct mlx5_core_dev, priv.fc_stats.work.work); struct mlx5_fc_stats *fc_stats = &dev->priv.fc_stats; - struct llist_node *tmplist = llist_del_all(&fc_stats->addlist); + /* Take dellist first to ensure that counters cannot be deleted before + * they are inserted. + */ + struct llist_node *dellist = llist_del_all(&fc_stats->dellist); + struct llist_node *addlist = llist_del_all(&fc_stats->addlist); struct mlx5_fc *counter = NULL, *last = NULL, *tmp; unsigned long now = jiffies; - if (tmplist || !list_empty(&fc_stats->counters)) + if (addlist || !list_empty(&fc_stats->counters)) queue_delayed_work(fc_stats->wq, &fc_stats->work, fc_stats->sampling_interval); - llist_for_each_entry(counter, tmplist, addlist) + llist_for_each_entry(counter, addlist, addlist) mlx5_fc_stats_insert(dev, counter); - tmplist = llist_del_all(&fc_stats->dellist); - llist_for_each_entry_safe(counter, tmp, tmplist, dellist) { + llist_for_each_entry_safe(counter, tmp, dellist, dellist) { list_del(&counter->list); mlx5_free_fc(dev, counter); -- cgit v1.2.3-59-g8ed1b