possible netgraph regression on freebsd 10.0-RC3

[Gleb Smirnoff]

On Thu, Jan 02, 2014 at 12:27:14PM +0100, Cedric Tabary wrote:
C> Hello,
C> 
C> I upgraded several FreeBSD servers from 9.2-STABLE to 10.0-RC3 and I
C> now have strange behavior of mpd-5.7.
C> 
C> Symptoms :
C> - mpd stops accepting connections (PPTP VPN), and stops accepting control
C> connectiosn also (on telnet and http).
C> - The only way to kill mpd is a SIGKILL
C> - after killing mpd, all ng interfaces are still up and forwarding
C>   trafic
C> - the only way to revert to normal operation is a server power-cycle,
C> software reboot just freeze the kernel.
C> 
C> dmesg shows a lot of :
C> sonewconn: pcb 0xfffff80006f61930: Listen queue overflow: 4 already in
C> queue awaiting acceptance
C> however I can't find pcb 0xfffff80006f61930 in netstat and there is no
C> flood, did I miss something ?
C> 
C> netstat -naA shows pptp control connections with non null Recv-Q
C> netstat -naA shows netgraph control sockets with non null Send-Q
C> In normal operation conditions, all Send-Q/Recv-Q are 0 on all those
C> control sockets.
C> 
C> Attached :
C> - dmesg
C> - netstat -naA (anonymized)
C> - lsof -n (anonymized)
C> 
C> FreeBSD xxx 10.0-RC3 FreeBSD 10.0-RC3 #0 r259778: Mon Dec 23
C> 23:27:58 UTC 2013     root at snap.freebsd.org:/usr/obj/usr/src/sys/GENERIC
C> amd64
C> 
C> All this is reproduced once every 2-3 days on 4 different servers.

We've had a fix in ng_ksocket after 10.0-RC3, but the symptoms of that
problem were somewhat different. However, it is worth updating.

-- 
Totus tuus, Glebius.