[LEDE-DEV] ath9k sta/wpa2 fails on 4.9

[Tim Harvey]

I've found that ath9k sta mode with wpa2 crypto is failing on lede
master with a 4.9 kernel but if I move back to the 4.4 kernel it
works. I'm testing this on the imx6 target.

I'm running wpa_supplican't manually for testing. Here's 4.9:
root at LEDE:/# cat << EOF > /var/run/wpa
> country=US
> network={
>         scan_ssid=1
>         ssid="testssid"
>         key_mgmt=WPA-PSK
>         psk="testpass"
>         proto=RSN
> }
> EOF
wpa_supplicant -i wlan0 -c /var/ruroot at LEDE:/# wpa_supplicant -i wlan0
-c /var/run/wpa -D nl80211
Successfully initialized wpa_supplicant
wpa_supplicant -i wlan0 -c /var/ruroot at LEDE:/# wpa_supplicant -i wlan0
-c /var/run/wpa -D nl80211
Successfully initialized wpa_supplicant
wlan0: SME: Trying to authenticat[  164.723884] wlan0: authenticate
with 02:1a:11:fc:d1:e3 (SSID='testssid' freq=2437 MHz)
[  157.912650] wlan0: send auth to 02:1a:11:fc:d1:e3 (try 1/3)
[  159.112796] wlan0: send auth to 02:1a:11:fc:d1:e3 (try 2/3)
[  159.992785] wlan0: send auth to 02:1a:11:fc:d1:e3 (try 3/3)
[  160.962781] wlan0: authentication with 02:1a:11:fc:d1:e3 timed out

wlan0: SME: Trying to authenticat[  164.723884] wlan0: authenticate
with 02:1a:11:fc:d1:e3
e with 02:1a:11:fc:d1:e3 (SSID='testssid' freq=2437 MHz)
[  164.742628] wlan0: send auth to 02:1a:11:fc:d1:e3 (try 1/3)
[  166.072802] wlan0: send auth to 02:1a:11:fc:d1:e3 (try 2/3)
[  166.952787] wlan0: send auth to 02:1a:11:fc:d1:e3 (try 3/3)
[  167.992781] wlan0: authentication with 02:1a:11:fc:d1:e3 timed out


and on 4.4 everything works ok:
root at LEDE:/# cat << EOF > /var/run/wpa
> country=US
> network={
>         scan_ssid=1
>         ssid="testssid"
>         key_mgmt=WPA-PSK
>         psk="testpass"
>         proto=RSN
> }
> EOF
wpa_supplicant -i wlan0 -c /var/run/wproot at LEDE:/# wpa_supplicant -i
wlan0 -c /var/run/wpa -D nl80211
Successfully initialized wpa_supplicant
[   91.081202] IPv6: ADDRCONF(NETDEV_UP): wlan0: link is not ready
wlan0: SME: Trying to authenticat[   94.077000] wlan0: authenticate
with 02:1a:11:fc:d1:e3
e with 02:1a:11:fc:d1:e3 (SSID='testssid' freq=2437 MHz)
[   94.095541] wlan0: send auth to 02:1a:11:fc:d1:e3 (try 1/3)
[   94.102998] wlan0: authenticated
wlan0: Trying to associate with 02:1a:11:fc:d1:e3 (SSID='testssid[
94.110957] wlan0: associate with 02:1a:11:fc:d1:e3 (try 1/3)
' freq=2437 MHz)
[   94.122579] wlan0: RX AssocResp from 02:1a:11:fc:d1:e3 (capab=0x411
status=0 aid=2)
[   94.130449] wlan0: associated
[   94.133533] IPv6: ADDRCONF(NETDEV_CHANGE): wlan0: link becomes ready
wlan0: Associated with 02:1a:11:fc:d1:e3
wlan0: CTRL-EVENT-SUBNET-STATUS-UPDATE status=0
wlan0: WPA: Key negotiation completed with 02:1a:11:fc:d1:e3 [PTK=CCMP GTK=CCMP]
wlan0: CTRL-EVENT-CONNECTED - Connection to 02:1a:11:fc:d1:e3
completed [id=0 id_str=]

I've seen the same issue on mainline as discussed on linux-wireless
here: https://www.spinics.net/lists/linux-wireless/msg160645.html

Is there perhaps a kernel config I'm missing in 4.9 that could be causing this?

Regards,

Tim