netdev - Cannot connect to netlink socket??

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Date:	Fri, 17 Jul 2015 14:29:19 -0700
From:	Ben Greear <greearb@...delatech.com>
To:	netdev <netdev@...r.kernel.org>
Subject: Cannot connect to netlink socket??

Any idea what can cause this?  The system was working fine earlier,
so it is compiled with netlink support, etc.

Last thing someone did was to add 258 mac-vlans on top of
an ethernet port.  Removing macvlan module did not improve
things.

'ifconfig -a' works fine.

This is on a 4.0.4 (+ local hacks) kernel, nothing overly weird in dmesg, and no
new dmesg info when this fails to work:

strace ip addr show

...

socket(PF_NETLINK, SOCK_RAW|SOCK_CLOEXEC, NETLINK_ROUTE) = 3
setsockopt(3, SOL_SOCKET, SO_SNDBUF, [32768], 4) = 0
setsockopt(3, SOL_SOCKET, SO_RCVBUF, [1048576], 4) = 0
bind(3, {sa_family=AF_NETLINK, pid=0, groups=00000000}, 12) = 0
getsockname(3, {sa_family=AF_NETLINK, pid=16631, groups=00000000}, [12]) = 0
sendto(3, "(\0\0\0\22\0\1\3%m\251U\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0"..., 40, 0, NULL, 0) = -1 ECONNREFUSED (Connection refused)
dup(2)                                  = 4
fcntl(4, F_GETFL)                       = 0x8002 (flags O_RDWR|O_LARGEFILE)
brk(0)                                  = 0x1679000
brk(0x169a000)                          = 0x169a000
brk(0)                                  = 0x169a000
fstat(4, {st_mode=S_IFCHR|0620, st_rdev=makedev(136, 3), ...}) = 0
mmap(NULL, 4096, PROT_READ|PROT_WRITE, MAP_PRIVATE|MAP_ANONYMOUS, -1, 0) = 0x7fb40d3c9000
write(4, "Cannot send dump request: Connec"..., 45Cannot send dump request: Connection refused
) = 45
close(4)                                = 0
munmap(0x7fb40d3c9000, 4096)            = 0
exit_group(1)                           = ?
+++ exited with 1 +++



A reboot 'fixed' things, and we have not been able to reproduce the
problem.


Thanks,
Ben

-- 
Ben Greear <greearb@...delatech.com>
Candela Technologies Inc  http://www.candelatech.com

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