From: Ricardo Dias <rdias@memsql.com>
To: Eric Dumazet <edumazet@google.com>
Cc: David Miller <davem@davemloft.net>,
Jakub Kicinski <kuba@kernel.org>,
Alexey Kuznetsov <kuznet@ms2.inr.ac.ru>,
Hideaki YOSHIFUJI <yoshfuji@linux-ipv6.org>,
netdev <netdev@vger.kernel.org>,
LKML <linux-kernel@vger.kernel.org>
Subject: Re: [PATCH] tcp: fix race condition when creating child sockets from syncookies
Date: Fri, 23 Oct 2020 17:48:25 +0100 [thread overview]
Message-ID: <20201023164825.GA321826@rdias-suse-pc.lan> (raw)
In-Reply-To: <CANn89i+OZF2HJQYT0FGtzyFeZMdof9RAfGXQRKUVY6Hg9ZPpcg@mail.gmail.com>
On Fri, Oct 23, 2020 at 06:36:29PM +0200, Eric Dumazet wrote:
> On Fri, Oct 23, 2020 at 6:06 PM Ricardo Dias <rdias@memsql.com> wrote:
>
> > And what about the loopback interface? Why couldn't the loopback
> > interface also use a single RX queue?
> >
>
> Loopback is using a per-cpu queue, with no crossing, for efficiency.
>
> That means : whenever a packet is sent on lo interface from CPU X, it
> is put on CPU X backlog queue.
>
> If the connect() and sendmsg() are run from different cpus, then the
> ACK (from last packet of 3WH) and the data packet might land on
> different queues.
In that case, I can change the patch to only iterate the ehash bucket
only when the listening socket is using the loopback interface, correct?
next prev parent reply other threads:[~2020-10-23 16:48 UTC|newest]
Thread overview: 11+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-10-23 11:13 [PATCH] tcp: fix race condition when creating child sockets from syncookies Ricardo Dias
2020-10-23 14:03 ` Eric Dumazet
2020-10-23 15:51 ` Ricardo Dias
2020-10-23 15:56 ` Eric Dumazet
2020-10-23 16:06 ` Ricardo Dias
2020-10-23 16:36 ` Eric Dumazet
2020-10-23 16:48 ` Ricardo Dias [this message]
2020-10-23 16:51 ` Eric Dumazet
2020-10-23 16:54 ` Ricardo Dias
2020-10-23 14:25 ` kernel test robot
2020-10-26 8:27 ` Dan Carpenter
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