ref_tracker: add a count of untracked references

We are still chasing a netdev refcount imbalance, and we suspect
we have one rogue dev_put() that is consuming a reference taken
from a dev_hold_track()

To detect this case, allow ref_tracker_alloc() and ref_tracker_free()
to be called with a NULL @trackerp parameter, and use a dedicated
refcount_t just for them.

Signed-off-by: Eric Dumazet <edumazet@google.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

1 files changed, 2 insertions, 0 deletions

diff --git a/include/linux/ref_tracker.h b/include/linux/ref_tracker.h
index a443abda937d..9ca353ab712b 100644
--- a/include/linux/ref_tracker.h
+++ b/include/linux/ref_tracker.h
@@ -13,6 +13,7 @@ struct ref_tracker_dir {
 	spinlock_t		lock;
 	unsigned int		quarantine_avail;
 	refcount_t		untracked;
+	refcount_t		no_tracker;
 	bool			dead;
 	struct list_head	list; /* List of active trackers */
 	struct list_head	quarantine; /* List of dead trackers */
@@ -29,6 +30,7 @@ static inline void ref_tracker_dir_init(struct ref_tracker_dir *dir,
 	dir->quarantine_avail = quarantine_count;
 	dir->dead = false;
 	refcount_set(&dir->untracked, 1);
+	refcount_set(&dir->no_tracker, 1);
 	stack_depot_init();
 }