From: Jakub Kicinski <kuba@kernel.org>
To: Cong Wang <xiyou.wangcong@gmail.com>
Cc: netdev@vger.kernel.org, Cong Wang <cong.wang@bytedance.com>,
shaozhengchao <shaozhengchao@huawei.com>,
Paolo Abeni <pabeni@redhat.com>,
Tom Herbert <tom@herbertland.com>,
Eric Dumazet <edumazet@google.com>
Subject: Re: [Patch net] kcm: fix a race condition in kcm_recvmsg()
Date: Fri, 28 Oct 2022 16:27:56 -0700 [thread overview]
Message-ID: <20221028162756.6c1f64f0@kernel.org> (raw)
In-Reply-To: <Y1wrp4pL4BmUL0LE@pop-os.localdomain>
On Fri, 28 Oct 2022 12:21:11 -0700 Cong Wang wrote:
> On Tue, Oct 25, 2022 at 04:02:22PM -0700, Jakub Kicinski wrote:
> > On Sat, 22 Oct 2022 19:30:44 -0700 Cong Wang wrote:
> > > + spin_lock_bh(&mux->rx_lock);
> > > KCM_STATS_INCR(kcm->stats.rx_msgs);
> > > skb_unlink(skb, &sk->sk_receive_queue);
> > > + spin_unlock_bh(&mux->rx_lock);
> >
> > Why not switch to __skb_unlink() at the same time?
> > Abundance of caution?
>
> What gain do we have? Since we have rx_lock, skb queue lock should never
> be contended?
I was thinking mostly about readability, the performance is secondary.
Other parts of the code use unlocked skb queue helpers so it may be
confusing to a reader why this on isn't, and therefore what lock
protects the queue. But no strong feelings.
next prev parent reply other threads:[~2022-10-28 23:28 UTC|newest]
Thread overview: 7+ messages / expand[flat|nested] mbox.gz Atom feed top
2022-10-23 2:30 [Patch net] kcm: fix a race condition in kcm_recvmsg() Cong Wang
2022-10-25 23:02 ` Jakub Kicinski
2022-10-25 23:49 ` Eric Dumazet
2022-10-28 19:24 ` Cong Wang
2022-10-28 19:21 ` Cong Wang
2022-10-28 23:27 ` Jakub Kicinski [this message]
2022-11-01 20:52 ` Cong Wang
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