From: Francesco Ruggeri <fruggeri@arista.com>
To: open list <linux-kernel@vger.kernel.org>,
netdev <netdev@vger.kernel.org>,
xiyou.wangcong@gmail.com, ap420073@gmail.com, andriin@fb.com,
Eric Dumazet <edumazet@google.com>,
jiri@mellanox.com, ast@kernel.org,
Jakub Kicinski <kuba@kernel.org>,
David Miller <davem@davemloft.net>,
Francesco Ruggeri <fruggeri@arista.com>
Subject: Re: [PATCH] net: make netdev_wait_allrefs wake-able
Date: Wed, 16 Sep 2020 23:33:21 -0700 [thread overview]
Message-ID: <CA+HUmGjX4_4_UXWNn=EehQ_3QtFPZq8RJU146r-nc0nA8apx7w@mail.gmail.com> (raw)
In-Reply-To: <20200917020021.0860995C06B9@us180.sjc.aristanetworks.com>
> static inline void dev_put(struct net_device *dev)
> {
> + struct task_struct *destroy_task = dev->destroy_task;
> +
> this_cpu_dec(*dev->pcpu_refcnt);
> + if (destroy_task)
> + wake_up_process(destroy_task);
> }
I just realized that this introduces a race, if dev_put drops the last
reference, an already running netdev_wait_allrefs runs to completion
and then dev_put tries to wake it up.
Any suggestions on how to avoid this without resorting to
locking?
Thanks,
Francesco
next prev parent reply other threads:[~2020-09-17 6:33 UTC|newest]
Thread overview: 4+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-09-17 2:00 [PATCH] net: make netdev_wait_allrefs wake-able Francesco Ruggeri
2020-09-17 6:33 ` Francesco Ruggeri [this message]
2020-09-17 6:51 ` Eric Dumazet
2020-09-17 16:17 ` Francesco Ruggeri
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