FreeBSD LAGG port crash

[Lakshmi Narasimhan Sundararajan]

Hi Team,
I am seeing a crash with 10.1 stable which is not seen in 11-CURRENT.
This is with lagg port operations, the below simple sequence of cmds cause
system crash.

ifconfig lagg0 create
ifconfig lagg0 laggproto failover laggport le0
ifconfig lagg0 /* crash here */

See below for the backtraces.
The issue is reproducible in laggproto failover or loadbalance, but not
with lacp.

Is this a known issue?
Is there an MFC to 10.1 STABLE, that is known to fix this issue?
Is anyone looking at this currently?

Any inputs on this would be much appreciated.

Best regards,
LN
====================== backtrace snip ===============

KDB: stack backtrace:
db_trace_self_wrapper() at db_trace_self_wrapper+0x2b/frame
0xfffffe202122c1e0
kdb_backtrace() at kdb_backtrace+0x39/frame 0xfffffe202122c290
panic() at panic+0x155/frame 0xfffffe202122c310
trap_fatal() at trap_fatal+0x38f/frame 0xfffffe202122c370
trap_pfault() at trap_pfault+0x308/frame 0xfffffe202122c410
trap() at trap+0x47a/frame 0xfffffe202122c620
calltrap() at calltrap+0x8/frame 0xfffffe202122c620
--- trap 0xc, rip = 0xffffffff80e15991, rsp = 0xfffffe202122c6e0, rbp =
0xfffffe202122c710 ---
lacp_portreq() at lacp_portreq+0x11/frame 0xfffffe202122c710
lagg_port2req() at lagg_port2req+0x62/frame 0xfffffe202122c740
lagg_ioctl() at lagg_ioctl+0x2db/frame 0xfffffe202122c820
ifioctl() at ifioctl+0x162b/frame 0xfffffe202122c8e0
kern_ioctl() at kern_ioctl+0x255/frame 0xfffffe202122c950
sys_ioctl() at sys_ioctl+0x13c/frame 0xfffffe202122c9a0
amd64_syscall() at amd64_syscall+0x351/frame 0xfffffe202122cab0
Xfast_syscall() at Xfast_syscall+0xfb/frame 0xfffffe202122cab0
--- syscall (54, FreeBSD ELF64, sys_ioctl), rip = 0x8011b5b9a, rsp =
0x7fffffffd8e8, rbp = 0x7fffffffe3a0 ---
================================================

-- 


DISCLAIMER

The information in this e-mail is confidential and may be subject to legal 
privilege. It is intended solely for the addressee. Access to this e-mail 
by anyone else is unauthorized. If you have received this communication in 
error, please address with the subject heading "Received in error," send to 
it at msystechnologies.com,  then delete the e-mail and destroy any copies of 
it. If you are not the intended recipient, any disclosure, copying, 
distribution or any action taken or omitted to be taken in reliance on it, 
is prohibited and may be unlawful. The views, opinions, conclusions and 
other information expressed in this electronic mail and any attachments are 
not given or endorsed by the company unless otherwise indicated by an 
authorized representative independent of this message.
MSys cannot guarantee that e-mail communications are secure or error-free, 
as information could be intercepted, corrupted, amended, lost, destroyed, 
arrive late or incomplete, or contain viruses, though all reasonable 
precautions have been taken to ensure no viruses are present in this e-mail. 
As our company cannot accept responsibility for any loss or damage arising 
from the use of this e-mail or attachments we recommend that you subject 
these to your virus checking procedures prior to use