why "underflow" happens?

[hong zhang]

List,

When wpa-psk TKIP key rotation happens during connection, "underflow" is complained and then disconnected. What does it means?

/*****************
10-08 08:27:51.153 D/wpa_supplicant( 1791):   EAPOL-Key type=2

10-08 08:27:51.153 D/wpa_supplicant( 1791):   key_info 0x13a1 (ver=1 keyidx=2 rsvd=0 Group Ack MIC Secure Encr)

10-08 08:27:51.153 D/wpa_supplicant( 1791):   key_length=32 key_data_length=32

10-08 08:27:51.153 D/wpa_supplicant( 1791): WPA: RX message 1 of Group Key Handshake from 58:8d:09:b1:14:00 (ver=1)

10-08 08:27:51.153 D/wpa_supplicant( 1791): WPA: EAPOL-Key Key Data underflow (ie=29 len=72 pos=0)

10-08 08:27:51.153 I/wpa_supplicant( 1791): WPA: No GTK IE in Group Key msg 1/2

10-08 08:27:51.153 D/wpa_supplicant( 1791): State: COMPLETED -> GROUP_HANDSHAKE

10-08 08:27:51.153 I/wpa_supplicant( 1791): CTRL-EVENT-STATE-CHANGE id=1 state=6 BSSID=00:00:00:00:00:00
/*********************

I checked wpa.c and could not tell what it means.

Any help will be appreciated.

---henry