monitor mode weirdness

From: Gerald Britton (
Date: 2002-09-03 01:06:20 UTC

The driver spews a lot of warnings about packet lengths being huge during monitor mode. I know this has been mentioned before, but I thought it ought to atleast be periodically looked at. IIRC, the best guess at the problem was a race in reading the BAP registers. Below is a log of a section of kernel messages during monitor mode. In the larger dumps of RX status, A1 always appears to be an address on the network (in this log, the first is a station, and the second has A1 as the AP's address). All the other addresses in the dump appear to be bogus.

This was captured using the current CVS driver with the pci prism2.5 in my thinkpad t23, i've got the following firmware loaded onto the card:

wlan0: NIC: id=0x8013 v1.0.0
wlan0: PRI: id=0x15 v1.1.0
wlan0: STA: id=0x1f v1.4.9

I also noticed that yanking my PCMCIA wlan1 while doing similar monitoring activity made things very unhappy with keventd oopsing out (presumably a scheduled tasklet or similar is not properly protected against the hardware being removed).

wlan0: prism2_rx_80211: len(18765) > MAX(2304)
wlan0: prism2_rx_80211: len(19786) > MAX(2304)
wlan0: Received frame with invalid length 0xc6c6
wlan0: RX status=0x0700 (port=7, type=0, fcserr=0)

   silence=3 signal=47 rate=20 rxflow=0; jiffies=2528604

   FC=0x00d4 (type=1:13) dur=0x0000 seq=0x6b20 data_len=50886
   A1=00:40:96:30:1f:24 A2=ab:ae:0e:00:00:00
   A3=00:00:62:6c:75:65 A4=69:74:74:65:6e:00
   dst=4a:a6:3d:d1:16:42 src=8f:bd:cf:91:fc:16 len=15873
wlan0: prism2_rx_80211: len(14958) > MAX(2304)
wlan0: prism2_rx_80211: len(26989) > MAX(2304)
wlan0: prism2_rx_80211: len(29541) > MAX(2304)
wlan0: prism2_rx_80211: len(14897) > MAX(2304)
wlan0: Received frame with invalid length 0x862a
wlan0: RX status=0x0700 (port=7, type=0, fcserr=0)

   silence=3 signal=49 rate=20 rxflow=0; jiffies=2528636

   FC=0x00d4 (type=1:13) dur=0x0000 seq=0x5db3 data_len=34346
   A1=00:04:5a:dd:45:b7 A2=4f:35:69:63:65:6c
   A3=65:73:73:00:6e:ff A4=32:9d:15:4a:a2:2a
   dst=2d:e6:ad:45:80:01 src=06:09:00:00:00:00 len=101 wlan0: prism2_rx_80211: len(27489) > MAX(2304) wlan0: prism2_rx_80211: len(28274) > MAX(2304)

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