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From: Andrew Savchenko <bircoph@gmail.com>
To: Eric Dumazet <eric.dumazet@gmail.com>
Cc: netdev@vger.kernel.org
Subject: Re: [BUG] Kernel recieves DNS reply, but doesn't deliver it to a waiting application
Date: Sun, 14 Oct 2012 03:11:19 +0400	[thread overview]
Message-ID: <20121014031119.a60263d6.bircoph@gmail.com> (raw)
In-Reply-To: <1350135860.21172.14606.camel@edumazet-glaptop>

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Hello,

On Sat, 13 Oct 2012 15:44:20 +0200 Eric Dumazet wrote:
> On Sat, 2012-10-13 at 16:36 +0400, Andrew Savchenko wrote:
> > On Wed, 3 Oct 2012 23:25:48 +0400 Andrew Savchenko wrote:
> > > I encountered a very weird bug: after a while of uptime kernel stops to deliver
> > > DNS reply to applications. Tcpdump shows that correct reply is recieved, but 
> > > strace shows inquiring application never recieves it and ends with timeout,
> > > epoll_wait() always returns 0:
> > > a slice from: $ host kernel.org 8.8.8.8:
[...]
> > > In a few days I'll try 3.4.12 (I need to rebuild kernel anyway due to unrelated
> > > issue) and will report if this bug will occur again. But please note it may
> > > take several weeks to check this.
> > 
> > I got this problem again with 3.4.12 kernel. System lasted less than
> > a week and reboot was the only option...
> 
> You should investigate and check where the incoming packet is lost
> 
> Tools :
> 
> netstat -s
> 
> drop_monitor module and dropwatch command
> 
> cat /proc/net/udp

Thank you for you reply; I updated my kernel to 3.4.14, enabled
CONFIG_NET_DROP_MONITOR, and installed dropwatch utility.

I will report back when the bug will struck again.
This may take a weak or two, however.

Best regards,
Andrew Savchenko

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  reply	other threads:[~2012-10-13 23:11 UTC|newest]

Thread overview: 16+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2012-10-03 19:25 Kernel recieves DNS reply, but doesn't deliver it to a waiting application Andrew Savchenko
2012-10-13 12:36 ` [BUG] " Andrew Savchenko
2012-10-13 13:44   ` Eric Dumazet
2012-10-13 23:11     ` Andrew Savchenko [this message]
2012-10-20 23:25       ` Andrew Savchenko
2012-10-21 12:52         ` Eric Dumazet
2012-10-22  3:36           ` Andrew Savchenko
2012-10-22  6:48             ` Eric Dumazet
2012-10-22 21:27               ` Andrew Savchenko
2012-12-12  8:27                 ` Andrew Savchenko
2012-12-23 11:06                   ` Andrew Savchenko
2012-12-28 18:11                     ` Eric Dumazet
2013-01-16 16:36                       ` Andrew Savchenko
2013-02-04 13:39                         ` Andrew Savchenko
2013-02-04 15:21                           ` Eric Dumazet
2012-11-23  7:45         ` Andrew Savchenko

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