This linux-wireless patch discussion appears to describe the cause of the issue but its not entirely clear if the patch was subsequently reverted nor whether the offending behaviour is present in this version of the kernel.
"And this introduces the same panic again :( The problem is the following: We don't pass the skb in the same state back to mac80211 as we got it. When inserting the l2pad we're moving the header and thus reduce headroom. This patch modifies the bahavior during l2pad removal to not move the header back into its old position but instead moves the payload. Thus the skb keeps the reduced headroom. If this skb gets requeued into rt2x00 (which can happen when the frame wasn't acked and the according STA is known to e in powersave mode) the header and payload get aligned again further reducing headroom which results in a too small headroom for the TXWI and thus a skb_under_panic." http://rt2x00.serialmonkey.com/pipermail/users_rt2x00.serialmonkey.com/2010-November/002457.html >From looking at the hostapd log just prior to the panic there was a timeout which might imply the kernel would need to requeue the packet several times: Dec 7 07:28:12 jeeves hostapd: wlan0: WPA rekeying GTK Dec 7 07:28:12 jeeves hostapd: wlan0: STA 90:21:55:7b:71:d6 WPA: sending 1/2 msg of Group Key Handshake Dec 7 07:28:12 jeeves hostapd: wlan0: STA 00:23:76:d4:e0:44 WPA: sending 1/2 msg of Group Key Handshake Dec 7 07:28:12 jeeves hostapd: wlan0: STA 00:1f:3b:bd:74:85 WPA: sending 1/2 msg of Group Key Handshake Dec 7 07:28:12 jeeves hostapd: wlan0: STA 00:1f:3b:bd:74:85 WPA: received EAPOL-Key frame (2/2 Group) Dec 7 07:28:12 jeeves hostapd: wlan0: STA 00:1f:3b:bd:74:85 WPA: group key handshake completed (RSN) Dec 7 07:28:12 jeeves hostapd: wlan0: STA 90:21:55:7b:71:d6 WPA: EAPOL-Key timeout Dec 7 07:28:12 jeeves hostapd: wlan0: STA 90:21:55:7b:71:d6 WPA: sending 1/2 msg of Group Key Handshake Dec 7 07:28:12 jeeves hostapd: wlan0: STA 00:23:76:d4:e0:44 WPA: EAPOL-Key timeout Dec 7 07:28:12 jeeves hostapd: wlDec 7 07:44:36 jeeves hostapd: wlan0: STA 00:1f:3b:bd:74:85 IEEE 802.11: authentication OK (open system) ** Changed in: linux (Ubuntu) Status: Incomplete => Confirmed -- You received this bug notification because you are a member of Ubuntu Bugs, which is subscribed to Ubuntu. https://bugs.launchpad.net/bugs/1087591 Title: Panic in rt2x00lib To manage notifications about this bug go to: https://bugs.launchpad.net/ubuntu/+source/linux/+bug/1087591/+subscriptions -- ubuntu-bugs mailing list ubuntu-bugs@lists.ubuntu.com https://lists.ubuntu.com/mailman/listinfo/ubuntu-bugs
