netdev - Problem with tun driver

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Date:	Thu, 16 Sep 2010 10:30:42 +0200
From:	Martín Ferrari <martin.ferrari@...il.com>
To:	netdev <netdev@...r.kernel.org>
Cc:	"Eric W. Biederman" <ebiederm@...stanetworks.com>
Subject: Problem with tun driver

(copying Eric as he seems to have been writing patches for tun to work
with netns)

Hello,

I am seeing a strange behaviour with the TUN driver when using it
inside a network name space, hope that somebody can help me...

I still couldn' t reproduce this problem outside of my program, so it
complicates things more. What I am doing is creating a tap device,
moving it into a namespace and then passing the filedescriptor to
another process which in turn starts reading from it.

>From strace I see that many reads succeed (Ipv6 autoconfig and arp
requests), and at some point, read returns EBADF. I don't see the
other processes doing anything suspicious on it at the same time. From
reading the kernel sources, it seems to be failing the call to
tun_get(), but I don' t understand how that could be happening...

Any pointers?

Thanks

-- 
Martín Ferrari
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