[PATCH 4.19 265/293] net/mlx5: Fix potential sleeping in atomic context
From: Greg Kroah-Hartman
Date: Mon Sep 20 2021 - 14:00:47 EST
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;
}