[PATCH] net: core: devlink.c: Hold devlink->lock from the beginning of devlink_dpipe_table_register()

From: madhuparnabhowmik10
Date: Sun Feb 23 2020 - 06:22:55 EST


From: Madhuparna Bhowmik <madhuparnabhowmik10@xxxxxxxxx>

devlink_dpipe_table_find() should be called under either
rcu_read_lock() or devlink->lock. devlink_dpipe_table_register()
calls devlink_dpipe_table_find() without holding the lock
and acquires it later. Therefore hold the devlink->lock
from the beginning of devlink_dpipe_table_register().

Suggested-by: Jiri Pirko <jiri@xxxxxxxxxxxx>
Signed-off-by: Madhuparna Bhowmik <madhuparnabhowmik10@xxxxxxxxx>
---
net/core/devlink.c | 21 ++++++++++++++-------
1 file changed, 14 insertions(+), 7 deletions(-)

diff --git a/net/core/devlink.c b/net/core/devlink.c
index 4c63c9a4c09e..e82750bdc496 100644
--- a/net/core/devlink.c
+++ b/net/core/devlink.c
@@ -6838,26 +6838,33 @@ int devlink_dpipe_table_register(struct devlink *devlink,
void *priv, bool counter_control_extern)
{
struct devlink_dpipe_table *table;
-
- if (devlink_dpipe_table_find(&devlink->dpipe_table_list, table_name))
- return -EEXIST;
+ int err = 0;

if (WARN_ON(!table_ops->size_get))
return -EINVAL;

+ mutex_lock(&devlink->lock);
+
+ if (devlink_dpipe_table_find(&devlink->dpipe_table_list, table_name)) {
+ err = -EEXIST;
+ goto unlock;
+ }
+
table = kzalloc(sizeof(*table), GFP_KERNEL);
- if (!table)
- return -ENOMEM;
+ if (!table) {
+ err = -ENOMEM;
+ goto unlock;
+ }

table->name = table_name;
table->table_ops = table_ops;
table->priv = priv;
table->counter_control_extern = counter_control_extern;

- mutex_lock(&devlink->lock);
list_add_tail_rcu(&table->list, &devlink->dpipe_table_list);
+unlock:
mutex_unlock(&devlink->lock);
- return 0;
+ return err;
}
EXPORT_SYMBOL_GPL(devlink_dpipe_table_register);

--
2.17.1