netdev - Re: [PATCH net] net/sched: act_mirred: Don't zero blockid when netns is going down

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Message-ID: <CANn89iKk-mG3-QPUNymbcBJZxLH02Nqz0u+ZOtgRoDOPTXd7Fw@mail.gmail.com>
Date: Wed, 7 Feb 2024 22:32:38 +0100
From: Eric Dumazet <edumazet@...gle.com>
To: Victor Nogueira <victor@...atatu.com>
Cc: jhs@...atatu.com, xiyou.wangcong@...il.com, jiri@...nulli.us, 
	davem@...emloft.net, kuba@...nel.org, pabeni@...hat.com, 
	netdev@...r.kernel.org, kernel@...atatu.com, pctammela@...atatu.com
Subject: Re: [PATCH net] net/sched: act_mirred: Don't zero blockid when netns
 is going down

On Wed, Feb 7, 2024 at 9:54 PM Victor Nogueira <victor@...atatu.com> wrote:
>
> While testing tdc with parallel tests for mirred to block we caught an
> intermittent bug. The blockid was being zeroed out when a parallel net
> namespace was going down and, thus, giving us an incorrect blockid value(0)
> whenever we tried to dump the mirred action. Since we don't increment the
> block refcount in the control path (and only use the ID), we don't need to
> zero the blockid field whenever the net namespace is going down.
>

You mention netns being removed, but the issue is more about unregistering
a net device ?

Ie the following would also trigger the bug ?

ip link add dev dummy type dummy
ip link del dummy