[Bug 209198] iwn sometimes loses link on dhclient start

[bugzilla-noreply at freebsd.org]

https://bugs.freebsd.org/bugzilla/show_bug.cgi?id=209198

            Bug ID: 209198
           Summary: iwn sometimes loses link on dhclient start
           Product: Base System
           Version: 11.0-CURRENT
          Hardware: amd64
                OS: Any
            Status: New
          Severity: Affects Only Me
          Priority: ---
         Component: wireless
          Assignee: freebsd-wireless at FreeBSD.org
          Reporter: david at catwhisker.org
                CC: freebsd-amd64 at FreeBSD.org
                CC: freebsd-amd64 at FreeBSD.org

Created attachment 169878
  --> https://bugs.freebsd.org/bugzilla/attachment.cgi?id=169878&action=edit
dmesg output after "service netif restart wlan0" and logging in

Over the last several months, as I reboot my laptop to the "head" slice for its
daily update-in-place (by source rebuild), I've noticed that while the wlano
NIC (using iwn hardware) almost always "Just Works" when I boot stable/10, in
head, it's about a 50% probability that wpa_supplicant will start, bring up
wlan0, and keep link up after dhclient starts -- vs. dropping link once
dhclient starts, only to have dhclient continue to re-try, even though wlan0's
link has dropped.

In the latter case, I have found a circumvention (of sorts): After dhclient
finally times out and gives up, login (as root) on ttyv1, then issue "service
netif restart wlan0".  In my experience, this always makes it work again. (As I
use xdm, started via getty out of /etc/ttys, I then also issue "service xdm
stop".)

Per suggestion, I have augmented /etc/rc.conf with
'wlandebug_wlan0="state+scan+auth+assoc+crypto"' ... and while I did not
encounter the above-described issue on the first "head" boot this morning, I
did on the second, when the laptop was running:

FreeBSD g1-252.catwhisker.org 11.0-CURRENT FreeBSD 11.0-CURRENT #406 
r298919M/298920:1100106: Mon May  2 04:42:04 PDT 2016    
root at g1-252.catwhisker.org:/common/S4/obj/usr/src/sys/CANARY  amd64

For each of the "head" boots this morning, I booted verbosely; I have retained
a few log files from the second boot (where link was dropped), and managed to
attach one of them.  (I didn't see a way to attach multiple files -- other than
concatenating them into one single mess, which seemed a bit counterproductive.)

Note that the SSID of interest to me is "lmdhw-net".

-- 
You are receiving this mail because:
You are on the CC list for the bug.