net: add dev->dev_registered_tracker

Convert one dev_hold()/dev_put() pair in register_netdevice()
and unregister_netdevice_many() to dev_hold_track()
and dev_put_track().

This would allow to detect a rogue dev_put() a bit earlier.

Signed-off-by: Eric Dumazet <edumazet@google.com>
Link: https://lore.kernel.org/r/20220207184107.1401096-1-eric.dumazet@gmail.com
Signed-off-by: Jakub Kicinski <kuba@kernel.org>

diff --git a/include/linux/netdevice.h b/include/linux/netdevice.h
index 3fb6fb6..5f6e2c0 100644 (file)
--- a/include/linux/netdevice.h
+++ b/include/linux/netdevice.h
@@ -1948,6 +1948,8 @@ enum netdev_ml_priv_type {
  *     @dev_addr_shadow:       Copy of @dev_addr to catch direct writes.
  *     @linkwatch_dev_tracker: refcount tracker used by linkwatch.
  *     @watchdog_dev_tracker:  refcount tracker used by watchdog.
+ *     @dev_registered_tracker:        tracker for reference held while
+ *                                     registered
  *
  *     FIXME: cleanup struct net_device such that network protocol info
  *     moves out.
@@ -2282,6 +2284,7 @@ struct net_device {
        u8 dev_addr_shadow[MAX_ADDR_LEN];
        netdevice_tracker       linkwatch_dev_tracker;
        netdevice_tracker       watchdog_dev_tracker;
+       netdevice_tracker       dev_registered_tracker;
 };
 #define to_net_dev(d) container_of(d, struct net_device, dev)
 

diff --git a/net/core/dev.c b/net/core/dev.c
index f662c6a..66556a2 100644 (file)
--- a/net/core/dev.c
+++ b/net/core/dev.c
@@ -9683,8 +9683,10 @@ int register_netdevice(struct net_device *dev)
        linkwatch_init_dev(dev);
 
        dev_init_scheduler(dev);
-       dev_hold(dev);
+
+       dev_hold_track(dev, &dev->dev_registered_tracker, GFP_KERNEL);
        list_netdevice(dev);
+
        add_device_randomness(dev->dev_addr, dev->addr_len);
 
        /* If the device has permanent device address, driver should
@@ -10449,7 +10451,7 @@ void unregister_netdevice_many(struct list_head *head)
        synchronize_net();
 
        list_for_each_entry(dev, head, unreg_list) {
-               dev_put(dev);
+               dev_put_track(dev, &dev->dev_registered_tracker);
                net_set_todo(dev);
        }