The patch below does not apply to the 4.14-stable tree. If someone wants it applied there, or to any other stable or longterm tree, then please email the backport, including the original git commit id to stable@vger.kernel.org.
thanks,
greg k-h
------------------ original commit in Linus's tree ------------------
From ee27e330a953595903979ffdb84926843595a9fe Mon Sep 17 00:00:00 2001
From: Maor Gottlieb maorg@nvidia.com Date: Wed, 1 Sep 2021 11:48:13 +0300 Subject: [PATCH] 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 9fe8e3c204d6..fe501ba88bea 100644 --- 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; }