wpa-supplicant v0.7.2 stops roaming after a while

[Michel Marti]

I'll try again ;-)

on 04/28/2010 04:41 PM Michel Marti said the following:
> I noticed that after running for a while, wpa-supplicant (v0.7.2) stops roaming to a
> better AP altough the scan results clearly contain a (much) stronger AP.
> 
> Driver in use is madwifi (latest from 0.9.4 branch). I have set the background scan
> interval on the card to 30 seconds (iwpriv ath0 bgscanintvl 30).
> 

I had another look at my wpa-supplicant debug log file. The stronger AP somehow gets
permanently blacklisted, causing the wpa-supplicant to subsequently ignore it...

# grep '00:18.*blacklist' supplicant.log
1272466406.053706: Added BSSID 00:18:39:d4:63:a4 into blacklist
1272466420.241335: Removed BSSID 00:18:39:d4:63:a4 from blacklist
1272466497.852958: Added BSSID 00:18:39:d4:63:a4 into blacklist
1272466507.139660: Removed BSSID 00:18:39:d4:63:a4 from blacklist
1272466618.728815: Added BSSID 00:18:39:d4:63:a4 into blacklist
1272466627.775176: Removed BSSID 00:18:39:d4:63:a4 from blacklist
1272466629.992936: Added BSSID 00:18:39:d4:63:a4 into blacklist
1272466642.499455: BSSID 00:18:39:d4:63:a4 blacklist count incremented to 2
1272466644.329980: Removed BSSID 00:18:39:d4:63:a4 from blacklist
1272466646.274820: Added BSSID 00:18:39:d4:63:a4 into blacklist
1272466844.741239: BSSID 00:18:39:d4:63:a4 blacklist count incremented to 2

Later on:
1272466857.040626: 0: 00:18:39:d4:63:a4 ssid='4YEO' wpa_ie_len=28 rsn_ie_len=24 caps=0x11
1272466857.040711:    skip - blacklisted
...

# wpa_cli status
Selected interface 'ath0'
bssid=00:15:70:56:ff:90
ssid=4YEO
id=0
mode=station
pairwise_cipher=CCMP
group_cipher=CCMP
key_mgmt=WPA2-PSK
wpa_state=COMPLETED
ip_address=192.168.0.233


# wpa_cli scan_results
Selected interface 'ath0'
bssid / frequency / signal level / flags / ssid
00:18:39:d4:63:a4	2462	229	[WPA-PSK-TKIP+CCMP][WPA2-PSK-TKIP+CCMP][ESS]	4YEO
00:15:70:56:ff:90	2437	203	[WPA2-PSK-CCMP][ESS]	4YEO
[...snip...]

What could be the reason for the blacklisting of the AP?

Thanks,
- Michel