dev_put() releases a reference which didn't have a tracker. References without a tracker are accounted in the tracking code as "no_tracker". We can't free the tracker and then call dev_put(). The references themselves will be fine but the tracking code will think it's a double-release: refcount_t: decrement hit 0; leaking memory. IOW commit under fixes confused dev_put() (release never tracked reference) with __dev_put() (just release the reference, skipping the reference tracking infra). Since __netdev_put_lock() uses dev_put() we can't feed a previously tracked netdev ref into it. Let's flip things around. netdev_put(dev, NULL) is the same as dev_put(dev) so make netdev_put_lock() the real function and have __netdev_put_lock() feed it a NULL tracker for all the cases that were untracked. Fixes: d04686d9bc86 ("net: Implement netdev_nl_queue_create_doit") Signed-off-by: Jakub Kicinski --- CC: dw@davidwei.uk CC: skhawaja@google.com CC: bestswngs@gmail.com CC: razor@blackwall.org CC: daniel@iogearbox.net --- net/core/dev.h | 8 +++++++- net/core/dev.c | 16 +++++----------- 2 files changed, 12 insertions(+), 12 deletions(-) diff --git a/net/core/dev.h b/net/core/dev.h index 376bac4a82da..628bdaebf0ca 100644 --- a/net/core/dev.h +++ b/net/core/dev.h @@ -31,9 +31,15 @@ struct napi_struct * netdev_napi_by_id_lock(struct net *net, unsigned int napi_id); struct net_device *dev_get_by_napi_id(unsigned int napi_id); -struct net_device *__netdev_put_lock(struct net_device *dev, struct net *net); struct net_device *netdev_put_lock(struct net_device *dev, struct net *net, netdevice_tracker *tracker); + +static inline struct net_device * +__netdev_put_lock(struct net_device *dev, struct net *net) +{ + return netdev_put_lock(dev, net, NULL); +} + struct net_device * netdev_xa_find_lock(struct net *net, struct net_device *dev, unsigned long *index); diff --git a/net/core/dev.c b/net/core/dev.c index e7bc95cbd1fa..4a82983e8616 100644 --- a/net/core/dev.c +++ b/net/core/dev.c @@ -1060,16 +1060,18 @@ struct net_device *dev_get_by_napi_id(unsigned int napi_id) * This helper is intended for locking net_device after it has been looked up * using a lockless lookup helper. Lock prevents the instance from going away. */ -struct net_device *__netdev_put_lock(struct net_device *dev, struct net *net) +struct net_device * +netdev_put_lock(struct net_device *dev, struct net *net, + netdevice_tracker *tracker) { netdev_lock(dev); if (dev->reg_state > NETREG_REGISTERED || dev->moving_ns || !net_eq(dev_net(dev), net)) { netdev_unlock(dev); - dev_put(dev); + netdev_put(dev, tracker); return NULL; } - dev_put(dev); + netdev_put(dev, tracker); return dev; } @@ -1121,14 +1123,6 @@ netdev_get_by_index_lock_ops_compat(struct net *net, int ifindex) return __netdev_put_lock_ops_compat(dev, net); } -struct net_device * -netdev_put_lock(struct net_device *dev, struct net *net, - netdevice_tracker *tracker) -{ - netdev_tracker_free(dev, tracker); - return __netdev_put_lock(dev, net); -} - struct net_device * netdev_xa_find_lock(struct net *net, struct net_device *dev, unsigned long *index) -- 2.53.0