bin/57366: Automated test usr.sbin/tcpdump/t_tcpdump:promiscuous fails on Rpi3 with wifi active

[jspath55%gmail.com@localhost]

>Number:         57366
>Category:       bin
>Synopsis:       Automated test usr.sbin/tcpdump/t_tcpdump:promiscuous fails on Rpi3 with wifi active
>Confidential:   no
>Severity:       serious
>Priority:       medium
>Responsible:    bin-bug-people
>State:          open
>Class:          sw-bug
>Submitter-Id:   net
>Arrival-Date:   Tue Apr 18 13:55:01 +0000 2023
>Originator:     Jim Spath
>Release:        10.0_BETA
>Organization:
>Environment:
NetBSD arm64 10.0_BETA NetBSD 10.0_BETA (GENERIC64) #0: Mon Apr  3 18:36:09 UTC 2023  mkrepro%mkrepro.NetBSD.org@localhost:/usr/src/sys/arch/evbarm/compile/GENERIC64 evbarm

>Description:
I ran the automated test framework on a Raspberry Pi 3B, with the bwfm wifi configured as well as having wired ethernet, and found a test failure:

tps-count: 1
tp-start: 1681699000.402113, usr.sbin/tcpdump/t_tcpdump, 1
tc-start: 1681699000.402214, promiscuous
tc-so:Testing mue0
tc-so:Executing command [ /bin/sh -c tcpdump -c 1 -i mue0 ]
tc-so:Testing lo0
tc-so:Executing command [ /bin/sh -c tcpdump -c 1 -i lo0 ]
tc-so:Testing bwfm0
tc-se:[2]   Terminated              atf_check -s ignore -o ignore -e ignore -x "tc...
tc-so:Executing command [ /bin/sh -c tcpdump -c 1 -i bwfm0 ]
tc-end: 1681699006.611166, promiscuous, failed, Test case body returned a non-ok exit code, but this is not allowed
tp-end: 1681699006.622398, usr.sbin/tcpdump/t_tcpdump
info: time.end, Mon Apr 17 02:36:46 UTC 2023

$ /sbin/ifconfig -l
mue0 lo0 bwfm0

The test code references an historic PR:
PR kern/46328
"Switching an interface into and out of promiscuous mode locks up amd64 netbsd-6 system."

That refers to a different CPU architecture; I do not know if the same code runs on ARM CPU.

The prior PR includes this comment:
"Add a test case for PR kern/46328 (tested naively with tcpdump(8))."

I assume that implies the tcpdump command will reveal invalid states but am unclear what the expected exit code/output would mean.
As far as I can discern, all 3 interfaces are behaving well.
>How-To-Repeat:
This failure appeared on a Raspberry Pi 3 where the NetBSD kernel recognized the wifi; the failure was not seen on other models where wifi is not recognized.

So far, I have tried disabling wpa_supplicant which had no effect on the test result. I plan to try with interfaces disabled one-by-one.
>Fix:
Unknown.
Did not appear on a Pi02W as the bwfm driver is apparently not complied in that kernel.