On Thu, Feb 6, 2025 at 3:13 PM Antonio Quartulli a@unstable.cc wrote:

On 06/02/2025 15:04, Eric Dumazet wrote:

...

Add a device tracker to struct batadv_hard_iface to help debugging of network device refcount imbalances.

Signed-off-by: Eric Dumazet edumazet@google.com

net/batman-adv/hard-interface.c | 14 +++++--------- net/batman-adv/types.h | 3 +++ 2 files changed, 8 insertions(+), 9 deletions(-)

diff --git a/net/batman-adv/hard-interface.c b/net/batman-adv/hard-interface.c index 96a412beab2de9069c0f88e4cd844fbc0922aa18..9a3ae567eb12d0c65b25292d020462b6ad60b699 100644 --- a/net/batman-adv/hard-interface.c +++ b/net/batman-adv/hard-interface.c @@ -51,7 +51,7 @@ void batadv_hardif_release(struct kref *ref) struct batadv_hard_iface *hard_iface;

  hard_iface = container_of(ref, struct batadv_hard_iface, refcount);

• dev_put(hard_iface->net_dev);
  

• netdev_put(hard_iface->net_dev, &hard_iface->dev_tracker);
  
  kfree_rcu(hard_iface, rcu);
  

  }

@@ -875,15 +875,16 @@ batadv_hardif_add_interface(struct net_device *net_dev) ASSERT_RTNL();

  if (!batadv_is_valid_iface(net_dev))

•         goto out;
  

•         return NULL;
  
  

• dev_hold(net_dev);
  
  hard_iface = kzalloc(sizeof(*hard_iface), GFP_ATOMIC);
  if (!hard_iface)
  

•         goto release_dev;
  

•         return NULL;
  
  

• netdev_hold(net_dev, &hard_iface->dev_tracker, GFP_ATOMIC);
  hard_iface->net_dev = net_dev;
  

• hard_iface->soft_iface = NULL;
  hard_iface->if_status = BATADV_IF_NOT_IN_USE;
  
  

@@ -909,11 +910,6 @@ batadv_hardif_add_interface(struct net_device *net_dev) batadv_hardif_generation++;

  return hard_iface;

-release_dev:

• dev_put(net_dev);
  

-out:

• return NULL;
  

  }

  static void batadv_hardif_remove_interface(struct batadv_hard_iface *hard_iface)

diff --git a/net/batman-adv/types.h b/net/batman-adv/types.h index f491bff8c51b8bf68eb11dbbeb1a434d446c25f0..a73fc3ab7dd28ae2c8484c0d198a15437d49ea73 100644 --- a/net/batman-adv/types.h +++ b/net/batman-adv/types.h @@ -186,6 +186,9 @@ struct batadv_hard_iface { /** @net_dev: pointer to the net_device */ struct net_device *net_dev;

• /** @dev_tracker device tracker for @net_dev */
  

• netdevice_tracker  dev_tracker;
  

There are two blanks between type and member name. Is that intended?

Not intended. Also a : is missing :

I can submit a V2 if you want, or feel free to make the changes.

diff --git a/net/batman-adv/types.h b/net/batman-adv/types.h index a73fc3ab7dd28ae2c8484c0d198a15437d49ea73..8ac061379b6f72ef7f1d4e191888db2cc56376da 100644 --- a/net/batman-adv/types.h +++ b/net/batman-adv/types.h @@ -186,8 +186,8 @@ struct batadv_hard_iface { /** @net_dev: pointer to the net_device */ struct net_device *net_dev;

- /** @dev_tracker device tracker for @net_dev */ - netdevice_tracker dev_tracker; + /** @dev_tracker: device tracker for @net_dev */ + netdevice_tracker dev_tracker;

/** @refcount: number of contexts the object is used */ struct kref refcount;

...

• /** @refcount: number of contexts the object is used */
  struct kref refcount;
  
  

We also have hard_iface->soft_iface storing a pointer to the soft_iface (batX) netdev.

How about converting that to netdev_put/hold as well? See batadv_hardif_enable_interface() / batadv_hardif_disable_interface()

Sure, feel free to submit a patch for this one as well.

Thanks.