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

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Message-ID: <CANn89iLK_XokM_zBz-xNvU36pOv_gH5uSvUBLNKpK3z4zOaQkg@mail.gmail.com>
Date:   Fri, 3 Dec 2021 17:00:11 -0800
From:   Eric Dumazet <edumazet@...gle.com>
To:     Jakub Kicinski <kuba@...nel.org>
Cc:     Eric Dumazet <eric.dumazet@...il.com>,
        "David S . Miller" <davem@...emloft.net>,
        netdev <netdev@...r.kernel.org>,
        Dmitry Vyukov <dvyukov@...gle.com>
Subject: Re: [PATCH v2 net-next 00/23] net: add preliminary netdev refcount tracking

On Fri, Dec 3, 2021 at 4:47 PM Jakub Kicinski <kuba@...nel.org> wrote:
>
> 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.

Sure thing, I will insert a patch to fix this in the next round.

Thanks !