Re: linux-next: zillions of lockdep whinges in include/net/sock.h:1408

[Valdis.Kletnieks@vt.edu]

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On Thu, 21 Apr 2016 09:42:12 +0200, Hannes Frederic Sowa said:
> Hi,
>
> On Thu, Apr 21, 2016, at 02:30, Valdis Kletnieks wrote:
> > linux-next 20160420 is whining at an incredible rate - in 20 minutes of
> > uptime, I piled up some 41,000 hits from all over the place (cleaned up
> > to skip the CPU and PID so the list isn't quite so long):
>
> Thanks for the report. Can you give me some more details:
>
> Is this an nfs socket? Do you by accident know if this socket went
> through xs_reclassify_socket at any point? We do hold the appropriate
> locks at that point but I fear that the lockdep reinitialization
> confused lockdep.

It wasn't an NFS socket, as NFS wasn't even active at the time.  I'm reasonably
sure that multiple sockets were in play, given that tcp_v6_rcv and
udpv6_queue_rcv_skb were both implicated.  I strongly suspect that pretty much
any IPv6 traffic could do it - the frequency dropped off quite a bit when I
closed firefox, which is usually a heavy network hitter on my laptop.


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