netdev - Re: [PATCH net 1/1] net sched actions: decrement module reference count after table flush.

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Message-ID: <CAM_iQpW9E8UWDCVbqDqZ7pkjh5kTEO7W_=2Qk_aRUP4HMXypRQ@mail.gmail.com>
Date:   Fri, 24 Feb 2017 09:58:21 -0800
From:   Cong Wang <xiyou.wangcong@...il.com>
To:     Roman Mashak <mrv@...atatu.com>
Cc:     David Miller <davem@...emloft.net>,
        Linux Kernel Network Developers <netdev@...r.kernel.org>,
        Jamal Hadi Salim <jhs@...atatu.com>
Subject: Re: [PATCH net 1/1] net sched actions: decrement module reference
 count after table flush.

On Fri, Feb 24, 2017 at 8:00 AM, Roman Mashak <mrv@...atatu.com> wrote:
> When tc actions are loaded as a module and no actions have been installed,
> flushing them would result in actions removed from the memory, but modules
> reference count not being decremented, so that the modules would not be
> unloaded.
>
> Following is example with GACT action:
>
> % sudo modprobe act_gact
> % lsmod
> Module                  Size  Used by
> act_gact               16384  0
> %
> % sudo tc actions ls action gact
> %
> % sudo tc actions flush action gact
> % lsmod
> Module                  Size  Used by
> act_gact               16384  1
> % sudo tc actions flush action gact
> % lsmod
> Module                  Size  Used by
> act_gact               16384  2
> % sudo rmmod act_gact
> rmmod: ERROR: Module act_gact is in use
> ....
>
> After the fix:
> % lsmod
> Module                  Size  Used by
> act_gact               16384  0
> %
> % sudo tc actions add action pass index 1
> % sudo tc actions add action pass index 2
> % sudo tc actions add action pass index 3
> % lsmod
> Module                  Size  Used by
> act_gact               16384  3
> %
> % sudo tc actions flush action gact
> % lsmod
> Module                  Size  Used by
> act_gact               16384  0
> %
> % sudo tc actions flush action gact
> % lsmod
> Module                  Size  Used by
> act_gact               16384  0
> % sudo rmmod act_gact
> % lsmod
> Module                  Size  Used by
> %
>
> Signed-off-by: Roman Mashak <mrv@...atatu.com>
> Signed-off-by: Jamal Hadi Salim <jhs@...atatu.com>

Fixes commit f97017cdefefdb6a0e19266024b0c6f9fd411eeb ?

Acked-by: Cong Wang <xiyou.wangcong@...il.com>