From mboxrd@z Thu Jan  1 00:00:00 1970
From: David Ahern <dsa@cumulusnetworks.com>
Subject: Re: [PATCH net-next 0/3] l3mdev: Improve use with main table
Date: Thu, 20 Apr 2017 08:25:37 -0600
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To: Robert Shearman <rshearma@brocade.com>, davem@davemloft.net
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On 4/20/17 7:01 AM, Robert Shearman wrote:
>> The cached dst on sockets is one known place that causes a hang on a
>> delete. Basically the delete stalls until the sockets are closed. I have
>> a patch for sk_rx_dst which is the one I chased down last week.

I got to the bottom on the sk_rx_dst caching -- it is only a problem on
older kernels (e.g., our 4.1 kernels) and only with multicast udp
sockets. The early demux code in 4.1 is matching a listen socket when it
should not. The early demux code for mcast had some changes unrelated to
false matching that fixed the problem.