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 4.19-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-4.19 subdirectory. If you, or anyone else, feels it should not be added to the stable tree, please let <stable@xxxxxxxxxxxxxxx> know about it. >From ee27e330a953595903979ffdb84926843595a9fe Mon Sep 17 00:00:00 2001 From: Maor Gottlieb <maorg@xxxxxxxxxx> Date: Wed, 1 Sep 2021 11:48:13 +0300 Subject: net/mlx5: Fix potential sleeping in atomic context From: Maor Gottlieb <maorg@xxxxxxxxxx> 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@xxxxxxxxxx> Signed-off-by: Maor Gottlieb <maorg@xxxxxxxxxx> Signed-off-by: Saeed Mahameed <saeedm@xxxxxxxxxx> Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx> --- drivers/net/ethernet/mellanox/mlx5/core/fs_core.c | 5 ++--- 1 file changed, 2 insertions(+), 3 deletions(-) --- 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 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 curr_match->g = g; list_add_tail(&curr_match->list, &match_head->list); } -out: rcu_read_unlock(); return err; } Patches currently in stable-queue which might be from maorg@xxxxxxxxxx are queue-4.19/net-mlx5-fix-potential-sleeping-in-atomic-context.patch