From: Alexei Starovoitov <ast@plumgrid.com>
To: Daniel Borkmann <daniel@iogearbox.net>,
Cong Wang <cwang@twopensource.com>
Cc: David Miller <davem@davemloft.net>,
subramanian.vijay@gmail.com, netdev <netdev@vger.kernel.org>,
John Fastabend <john.r.fastabend@intel.com>,
Eric Dumazet <edumazet@google.com>, Thomas Graf <tgraf@suug.ch>,
Jamal Hadi Salim <jhs@mojatatu.com>
Subject: Re: [PATCH net] net: sched: fix call_rcu() race on classifier module unloads
Date: Wed, 20 May 2015 11:32:56 -0700 [thread overview]
Message-ID: <555CD358.7090604@plumgrid.com> (raw)
In-Reply-To: <555CCE89.10503@iogearbox.net>
On 5/20/15 11:12 AM, Daniel Borkmann wrote:
>
> Effectively, every in-tree classifier (rsvp is the only exception)
> is making use of call_rcu(). Moreover, moving this into every
> ->destroy() handler would also be unnecessary overhead, imho, as
> this is only relevant when we actually _unload_ a module.
+1
indeed unregister_tcf_proto_ops() is only called at module unload time.
So there is no overhead from this rcu_barrier(). It's actually
mandatory. All modules with rcu callbacks should do that.
Acked-by: Alexei Starovoitov <ast@plumgrid.com>
next prev parent reply other threads:[~2015-05-20 18:33 UTC|newest]
Thread overview: 8+ messages / expand[flat|nested] mbox.gz Atom feed top
2015-05-20 15:13 [PATCH net] net: sched: fix call_rcu() race on classifier module unloads Daniel Borkmann
2015-05-20 17:38 ` Cong Wang
2015-05-20 18:12 ` Daniel Borkmann
2015-05-20 18:30 ` Cong Wang
2015-05-20 18:32 ` Alexei Starovoitov [this message]
2015-05-20 18:36 ` Eric Dumazet
2015-05-20 18:01 ` Vijay Subramanian
2015-05-21 22:48 ` David Miller
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