Re: [PATCH v2 net-next 00/23] net: add preliminary netdev refcount tracking

On Thu,  2 Dec 2021 18:46:17 -0800 Eric Dumazet wrote:

Two first patches add a generic infrastructure, that will be used
to get tracking of refcount increments/decrements.

The general idea is to be able to precisely pair each decrement with
a corresponding prior increment. Both share a cookie, basically
a pointer to private data storing stack traces.

The third place adds dev_hold_track() and dev_put_track() helpers
(CONFIG_NET_DEV_REFCNT_TRACKER)

Then a series of 20 patches converts some dev_hold()/dev_put()
pairs to new hepers : dev_hold_track() and dev_put_track().

Hopefully this will be used by developpers and syzbot to
root cause bugs that cause netdevice dismantles freezes.

With CONFIG_PCPU_DEV_REFCNT=n option, we were able to detect
some class of bugs, but too late (when too many dev_put()
were happening).

Hi Eric, there's a handful of kdoc warnings added here:

include/linux/netdevice.h:2278: warning: Function parameter or member 'refcnt_tracker' not described in 'net_device'
include/net/devlink.h:679: warning: Function parameter or member 'dev_tracker' not described in 'devlink_trap_metadata'
include/linux/netdevice.h:2283: warning: Function parameter or member 'refcnt_tracker' not described in 'net_device'
include/linux/mroute_base.h:40: warning: Function parameter or member 'dev_tracker' not described in 'vif_device'

Would you mind following up? likely not worth re-spinning just for that.