kern/52899: Kernel panic with iwm

[dogan%tesmer.org.tr@localhost]

>Number:         52899
>Category:       kern
>Synopsis:       Kernel panic with iwm
>Confidential:   no
>Severity:       critical
>Priority:       high
>Responsible:    kern-bug-people
>State:          open
>Class:          sw-bug
>Submitter-Id:   net
>Arrival-Date:   Thu Jan 04 18:50:00 +0000 2018
>Originator:     Mustafa Dogan
>Release:        NetBSD 8.0_BETA (GENERIC) #0: Thu Jan  4 02:44:02 +03 2018
>Organization:
TESMER Temel Egitim ve Staj Merkezi
>Environment:
NetBSD localhost 8.0_BETA NetBSD 8.0_BETA (GENERIC) #0: Thu Jan  4 02:44:02 +03 2018  root@localhost:/root/OBJ/sys/arch/amd64/compile/GENERIC amd64
>Description:
NetBSD-8 src changes with ticket 456: "Improve MP-safety of interfaces (struct ifnet)" caused kernel panic on my (DELL) laptop with iwm. 
Kernel output is below:
...
boot device: sd0
root on sd0a dumps on sd0b
root file system type: ffs
kern.module.path=/stand/amd64/8.0/modules
iwm0: hw rev 0x210, fw ver 22.361476.0, address 3c:f8:62:xx:xx:xx
panic: kernel diagnostic assertion "if_is_deactivated(ifp)  || IFNET_LOCKED(ifp)"
 failed: file "/usr/src/sys/net/if.c", line 1819
fatal breakpoint trap in supervisor mode
trap type 1 code 0 rip 0xffffffff80224d95 cs 0x8 rflags 0x246 cr2 0x0xffff80008dac
e000 ilevel 0x4 rsp 0xfffffe810f06dd00
curlwp 0xfffffe827d446700 pid 0.82 lowest kstack 0xfffffe810f06a2c0
Stopped in pid 0.82 (system) at netbsd:breakpoint+0x5:  leave
db(0)>
>How-To-Repeat:
Compile GENERIC kernel with src tree dated after Jan 3, 2018 and reboot with it on hardware which has iwm.
>Fix: