This is a note to let you know that I've just added the patch titled net/mlx5: Fix potential sleeping in atomic context to the 5.4-stable tree which can be found at: http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary The filename of the patch is: net-mlx5-fix-potential-sleeping-in-atomic-context.patch and it can be found in the queue-5.4 subdirectory. If you, or anyone else, feels it should not be added to the stable tree, please let <stable@xxxxxxxxxxxxxxx> know about it. commit 2b2287395b11f7be3de5af54c02da542ddb28c31 Author: Maor Gottlieb <maorg@xxxxxxxxxx> Date: Wed Sep 1 11:48:13 2021 +0300 net/mlx5: Fix potential sleeping in atomic context [ Upstream commit ee27e330a953595903979ffdb84926843595a9fe ] 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@xxxxxxxxxx> Signed-off-by: Maor Gottlieb <maorg@xxxxxxxxxx> Signed-off-by: Saeed Mahameed <saeedm@xxxxxxxxxx> Signed-off-by: Sasha Levin <sashal@xxxxxxxxxx> diff --git a/drivers/net/ethernet/mellanox/mlx5/core/fs_core.c b/drivers/net/ethernet/mellanox/mlx5/core/fs_core.c index 739bf5dc5a25..5fe4e028567a 100644 --- a/drivers/net/ethernet/mellanox/mlx5/core/fs_core.c +++ b/drivers/net/ethernet/mellanox/mlx5/core/fs_core.c @@ -1606,9 +1606,9 @@ 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, ft_locked); - err = -ENOMEM; - goto out; + return -ENOMEM; } if (!tree_get_node(&g->node)) { kfree(curr_match); @@ -1617,7 +1617,6 @@ 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; }