From: Eric Dumazet <eric.dumazet@gmail.com>
To: Dan Akunis <dan.akunis@gmail.com>
Cc: labbott@redhat.com, David Miller <davem@davemloft.net>,
kuznet@ms2.inr.ac.ru, jmorris@namei.org, yoshfuji@linux-ipv6.org,
kaber@trash.net, samanthakumar@google.com, willemb@google.com,
netdev@vger.kernel.org, linux-kernel@vger.kernel.org
Subject: Re: [REGRESSION] Select hang with zero sized UDP packets
Date: Wed, 24 Aug 2016 06:02:15 -0700 [thread overview]
Message-ID: <1472043735.14381.69.camel@edumazet-glaptop3.roam.corp.google.com> (raw)
In-Reply-To: <2ABF798B42E64D9C89DEB806A2E636B5@mtl.com>
On Wed, 2016-08-24 at 11:22 +0300, Dan Akunis wrote:
> When select wakes up on a UDP socket, user is expecting to get data. Getting
> 0 from recvfrom() or whatever read function she uses, is a wrong attitude.
> I agree with David.
>
> The unit test that expects select to wake up is wrong and should be changed.
>
Please do not top post on netdev mailing list.
Program is fine and wont be changed to work around a kernel bug.
We definitely can send and receive UDP messages with 0 payload.
So select() should unblock when one such frame is received, otherwise
you could fill up the receive queue with a lot of frames like that and
when SO_RCVBUF limit is reached, block future messages.
UDP is a datagram protocol.
Bug fix is merged :
https://git.kernel.org/cgit/linux/kernel/git/davem/net.git/commit/?id=e83c6744e81abc93a20d0eb3b7f504a176a6126a
next prev parent reply other threads:[~2016-08-24 13:02 UTC|newest]
Thread overview: 8+ messages / expand[flat|nested] mbox.gz Atom feed top
2016-08-23 17:53 Laura Abbott
2016-08-23 18:25 ` David Miller
2016-08-23 19:03 ` Eric Dumazet
2016-08-23 20:06 ` Laura Abbott
2016-08-23 20:42 ` Eric Dumazet
2016-08-24 8:22 ` Dan Akunis
2016-08-24 13:02 ` Eric Dumazet [this message]
2016-08-24 13:42 ` One Thousand Gnomes
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