kern/85239: assigning an address to ng_fec(4) iface causes panic

Evgueni V. Gavrilov aquatique at
Thu Aug 25 01:40:18 GMT 2005

The following reply was made to PR kern/85239; it has been noted by GNATS.

From: "Evgueni V. Gavrilov" <aquatique at>
To: Maksim Yevmenkin <maksim.yevmenkin at>
Cc: bug-followup at, Brooks Davis <brooks at>
Subject: Re: kern/85239: assigning an address to ng_fec(4) iface causes panic
Date: Thu, 25 Aug 2005 08:34:53 +0700

 Maksim Yevmenkin wrote:
 >>I've applied Maksim's patch (with some modifications since 6.0-BETA3
 >>holds ng_fec.c 1.18, not 1.20)
 > ok. just to verify, you have applied the second patch? right? as
 > Brooks pointed out the first patch did not make required change in
 > ng_fec_ioctl() (call to ng_fec_init() was still using ifp pointer
 > instead of priv pointer).
 yes, of course
 slight modifications used because I've got the trouble with 6.0-BETA3, 
 this is the patch I've applied
 >>The short response: it works finally :)
 >>But assigning an address to fec iface being down causes frezze, so I
 >>made following startup:
 > i can not reproduce the freeze here :( i did simple test (below).
 > unfortunately i do not have hardware to recreate your setup here :(
 I suppose that in order to reproduce this issue you need to configure 
 Fast (Ether|Giga)Channel on switch ports too. I agree that it's not 
 always possible.
 > can you drop into the debugger (ctrl+alt+esc) and try to get a stack
 > trace? if you can not - could you please try to put some printf's into
 > /sys/netgraph/ng_fec.c to see where it locks up?
 I'll try to inviestigate this upon next scheduled downtime for this 
 machine. Unfortunately I can't put it down for a long time (that's the 
 reason of using ng_fec(4) on that machine: high availability).
 > beetle# ifconfig fec0 inet netmask
 > beetle# ifconfig fec0
 > fec0: flags=8803<UP,BROADCAST,SIMPLEX,MULTICAST> mtu 1500
 >         inet6 fe80::211:43ff:fe54:22c9%fec0 prefixlen 64 scopeid 0x4 
 >         inet netmask 0xffffff00 broadcast
 >         ether 00:00:00:00:00:00
 >         media: Ethernet none
 >         status: no carrier
 I suppose the issue is apparent only using several interfaces in the 
 ng_fec(4) bundle with Fast (Ether|Giga)Channel configured on switch ports.

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