From: Mark Mielke <mark@mark.mielke.cc>
To: Willy Tarreau <willy@w.ods.org>
Cc: "David S. Miller" <davem@davemloft.net>,
Olivier Galibert <galibert@pobox.com>,
linux-kernel@vger.kernel.org
Subject: Re: UDP recvmsg blocks after select(), 2.6 bug?
Date: Fri, 8 Oct 2004 11:27:01 -0400 [thread overview]
Message-ID: <20041008152701.GB13183@mark.mielke.cc> (raw)
In-Reply-To: <20041008064104.GF19761@alpha.home.local>
On Fri, Oct 08, 2004 at 08:41:04AM +0200, Willy Tarreau wrote:
> On Wed, Oct 06, 2004 at 05:29:59PM -0700, David S. Miller wrote:
> > It absolutely does help the programs not using select(), using
> > blocking sockets, and not expecting -EAGAIN.
> As I asked in a previous mail in this overly long thread, why not returning
> zero bytes at all. It is perfectly valid to receive an UDP packet with 0
> data bytes, and any application should be able to support this case anyway.
> In case of TCP, this would be a problem because the app would think it
> indicates the last byte has been received. But in case of UDP, there is no
> problem.
0 isn't correct either. No zero length packet was successfully received.
I agree with the current read() behaviour. It's the select() behaviour
that I consider to be wrong. Patching return values is just a hacky way
of avoiding the issue.
The issue can be more easily avoided by saying 'the Linux developers
believe that the use of select() with blocking file descriptors is
invalid or not recommended, and have chosen not to ensure that this
use of system calls is reliable'. "We're not POSIX compliant in this
case" isn't good enough for me. One acknowledges the issue. The other
ignores it.
Cheers,
mark
--
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next prev parent reply other threads:[~2004-10-08 15:32 UTC|newest]
Thread overview: 191+ messages / expand[flat|nested] mbox.gz Atom feed top
2004-10-06 14:52 Joris van Rantwijk
2004-10-06 15:01 ` David S. Miller
2004-10-06 15:13 ` Chris Friesen
2004-10-06 15:15 ` Richard B. Johnson
2004-10-06 15:21 ` David S. Miller
2004-10-06 15:29 ` Richard B. Johnson
2004-10-06 15:42 ` David S. Miller
2004-10-06 15:57 ` Chris Friesen
2004-10-06 15:44 ` Lars Marowsky-Bree
2004-10-07 1:16 ` Paul Jakma
2004-10-07 7:10 ` Chris Friesen
2004-10-07 11:53 ` Paul Jakma
2004-10-07 13:32 ` Martijn Sipkema
2004-10-07 12:53 ` Paul Jakma
2004-10-07 13:12 ` Richard B. Johnson
2004-10-07 14:07 ` Martijn Sipkema
2004-10-07 13:19 ` Paul Jakma
2004-10-07 13:36 ` Paul Jakma
2004-10-07 15:01 ` Jean-Sebastien Trottier
2004-10-07 16:20 ` Chris Friesen
2004-10-07 18:20 ` Hua Zhong
2004-10-07 18:33 ` Chris Friesen
2004-10-07 22:41 ` Martijn Sipkema
2004-10-07 21:49 ` Chris Friesen
2004-10-07 22:00 ` David S. Miller
2004-10-07 22:24 ` Chris Friesen
2004-10-07 22:26 ` David S. Miller
2004-10-07 22:39 ` Chris Friesen
2004-10-07 22:42 ` David S. Miller
2004-10-07 23:27 ` Chris Friesen
2004-10-08 0:04 ` Ben Greear
2004-10-08 2:51 ` Mark Mielke
2004-10-08 3:39 ` David S. Miller
2004-10-08 3:48 ` Mark Mielke
2004-10-08 3:59 ` David S. Miller
2004-10-07 23:19 ` Martijn Sipkema
2004-10-07 22:24 ` David S. Miller
2004-10-07 22:33 ` Alan Curry
2004-10-07 22:42 ` Mark Mielke
2004-10-07 22:47 ` David S. Miller
2004-10-07 23:00 ` Mark Mielke
2004-10-07 23:07 ` David S. Miller
2004-10-08 6:10 ` Theodore Ts'o
2004-10-08 15:20 ` Mark Mielke
2004-10-08 0:37 ` Lee Revell
2004-10-07 22:46 ` Hua Zhong
2004-10-07 22:48 ` David S. Miller
2004-10-07 23:17 ` Martijn Sipkema
2004-10-07 13:45 ` Alan Cox
2004-10-07 16:32 ` Martijn Sipkema
2004-10-07 14:50 ` Alan Cox
2004-10-07 21:58 ` mmap specification - was: ... select specification Andries Brouwer
2004-10-07 22:17 ` Chris Wedgwood
2004-10-07 22:34 ` Andries Brouwer
2004-10-07 22:32 ` Kyle Moffett
2004-10-07 22:46 ` Andries Brouwer
2004-10-07 23:30 ` Kyle Moffett
2004-10-08 9:19 ` Andries Brouwer
2004-10-09 21:10 ` Martijn Sipkema
2004-10-07 13:48 ` UDP recvmsg blocks after select(), 2.6 bug? Alan Cox
2004-10-07 14:57 ` Richard B. Johnson
2004-10-07 15:18 ` Adam Heath
2004-10-07 16:39 ` Martijn Sipkema
2004-10-07 16:09 ` Mark Mielke
2004-10-07 17:18 ` Chris Friesen
2004-10-06 15:31 ` Chris Friesen
2004-10-06 15:41 ` David S. Miller
2004-10-06 16:07 ` Richard B. Johnson
2004-10-06 16:57 ` Neil Horman
2004-10-06 15:59 ` Paul Jackson
2004-10-06 16:35 ` Martijn Sipkema
2004-10-06 15:30 ` Chris Friesen
2004-10-06 15:09 ` Richard B. Johnson
2004-10-06 15:18 ` bert hubert
2004-10-06 16:41 ` Alan Cox
2004-10-06 18:04 ` Joris van Rantwijk
2004-10-06 19:30 ` Andries Brouwer
2004-10-06 19:23 ` Alan Cox
2004-10-06 22:08 ` Martijn Sipkema
2004-10-06 20:25 ` Alan Cox
2004-10-06 22:15 ` Andries Brouwer
2004-10-06 22:32 ` David S. Miller
2004-10-06 23:25 ` YOSHIFUJI Hideaki / 吉藤英明
2004-10-06 23:11 ` Willy Tarreau
2004-10-06 19:43 ` Hua Zhong
2004-10-06 19:54 ` Chris Friesen
2004-10-06 19:59 ` Hua Zhong
2004-10-06 20:10 ` Chris Friesen
2004-10-06 21:45 ` Martijn Sipkema
2004-10-06 23:35 ` David S. Miller
2004-10-06 20:06 ` David S. Miller
2004-10-06 20:18 ` Chris Friesen
2004-10-06 20:26 ` Hua Zhong
2004-10-06 20:38 ` Andries Brouwer
2004-10-06 20:58 ` Joris van Rantwijk
2004-10-06 22:29 ` David S. Miller
2004-10-07 16:08 ` Adrian Phillips
2004-10-06 20:06 ` Olivier Galibert
2004-10-06 23:35 ` David S. Miller
2004-10-07 0:19 ` Olivier Galibert
2004-10-07 0:29 ` David S. Miller
2004-10-07 10:56 ` Martijn Sipkema
2004-10-08 6:41 ` Willy Tarreau
2004-10-08 15:27 ` Mark Mielke [this message]
2004-10-15 22:42 ` Robert White
2004-10-15 23:33 ` David Schwartz
2004-10-16 0:59 ` Chris Friesen
2004-10-16 2:35 ` Mark Mielke
2004-10-16 4:23 ` David Schwartz
2004-10-16 4:35 ` Mark Mielke
2004-10-16 4:58 ` David Schwartz
2004-10-16 6:25 ` Mark Mielke
2004-10-16 21:44 ` Roland Kuhn
2004-10-17 0:06 ` Mark Mielke
2004-10-17 0:30 ` David Schwartz
2004-10-17 14:47 ` Mark Mielke
2004-10-17 0:28 ` David Schwartz
2004-10-17 13:35 ` Lars Marowsky-Bree
2004-10-17 14:17 ` Buddy Lucas
2004-10-17 15:05 ` Mark Mielke
2004-10-17 15:40 ` Buddy Lucas
2004-10-17 16:13 ` Lee Revell
2004-10-17 17:35 ` Jesper Juhl
2004-10-17 18:04 ` Buddy Lucas
2004-10-17 18:06 ` Lars Marowsky-Bree
2004-10-17 18:21 ` Buddy Lucas
2004-10-17 20:04 ` Martijn Sipkema
2004-10-17 20:08 ` Lars Marowsky-Bree
2004-10-17 17:35 ` Martijn Sipkema
2004-10-17 17:33 ` Buddy Lucas
2004-10-17 19:58 ` Martijn Sipkema
2004-10-17 19:33 ` Buddy Lucas
2004-10-17 20:11 ` Lars Marowsky-Bree
2004-10-17 20:25 ` Buddy Lucas
2004-10-17 20:42 ` Martijn Sipkema
2004-10-17 20:02 ` Buddy Lucas
2004-10-17 18:53 ` David Schwartz
2004-10-17 19:26 ` Hua Zhong
2004-10-17 20:32 ` Martijn Sipkema
2004-10-17 19:21 ` Hua Zhong
2004-10-17 17:22 ` Lars Marowsky-Bree
2004-10-17 17:54 ` Buddy Lucas
2004-10-17 18:05 ` Lars Marowsky-Bree
2004-10-17 18:06 ` Mark Mielke
2004-10-20 21:31 ` H. Peter Anvin
2004-10-20 21:58 ` Chris Friesen
2004-10-20 22:00 ` H. Peter Anvin
2004-10-20 22:12 ` Chris Friesen
2004-10-20 23:16 ` David Schwartz
2004-10-21 1:03 ` Chris Friesen
2004-10-21 1:38 ` David Schwartz
2004-10-21 3:01 ` Michael Clark
2004-10-21 3:52 ` Michael Clark
2004-10-21 4:10 ` H. Peter Anvin
2004-10-21 5:06 ` Chris Friesen
2004-10-21 5:11 ` H. Peter Anvin
2004-10-21 5:50 ` Chris Friesen
2004-10-21 5:58 ` H. Peter Anvin
2004-10-21 15:18 ` Chris Friesen
2004-10-21 6:14 ` Michael Clark
2004-10-17 14:52 ` Mark Mielke
2004-10-16 18:25 ` Andries Brouwer
2004-10-17 0:28 ` David Schwartz
2004-10-17 12:22 ` Andries Brouwer
2004-10-16 10:24 ` Willy Tarreau
2004-10-16 13:21 ` Mark Mielke
2004-10-18 22:25 ` Robert White
2004-10-06 20:41 ` Neil Horman
2004-10-06 22:27 ` Chris Friesen
2004-10-06 23:32 ` Neil Horman
2004-10-06 23:36 ` David S. Miller
2004-10-07 19:31 ` David Schwartz
2004-10-07 22:36 ` Martijn Sipkema
2004-10-08 0:19 ` David Schwartz
2004-10-09 19:21 ` Martijn Sipkema
2004-10-09 18:28 ` David Schwartz
2004-10-09 18:49 ` Mark Mielke
2004-10-09 21:00 ` Martijn Sipkema
2004-10-09 22:59 ` Mark Mielke
2004-10-06 15:30 Dan Kegel
2004-10-07 4:50 Dan Kegel
2004-10-07 8:04 ` bert hubert
2004-10-07 8:28 ` Adam Heath
2004-10-07 10:38 ` Martijn Sipkema
2004-10-07 10:07 ` Adam Heath
2004-10-07 11:29 ` Martijn Sipkema
2004-10-07 18:16 linux
2004-10-09 12:07 ` Colin Phipps
[not found] <fa.haprsoi.8k8kbk@ifi.uio.no>
[not found] ` <fa.isqjio8.ok2coo@ifi.uio.no>
2004-10-09 13:24 ` Bodo Eggert
2004-10-19 1:21 John Pearson
2004-10-19 13:50 ` Colin Phipps
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