2013-04-17 13:56:57

by Cedric VONCKEN

[permalink] [raw]
Subject: RE: ath9k null pointer with mesh network

I understand why the ac pointer is null in ath_tx_aggr_wakeup

My wireless card receive packet, the ieee80211_rx function is
called. This function call indirectly ath_tx_aggr_wakeup function and my
kernel crash because the ac pointer is null.

The Ac pointer is null because the sta_state is set to
IEEE80211_STA_NONE, and on this state the function ath_tx_node_init (in
net/wireless/ath/ath9k/xmit.c) is not already called (call only when the
sta_state go to IEEE80211_STA_ASSOC from IEEE80211_STA_AUTH )

Have you any idea to fix it ?

The kernel panic call stack
ath_tx_aggr_wakeup+0x64/0xe4 [ath9k] (unreliable)
[ 128.340486] [c7ffbd10] [c92b0b34] ath9k_deinit_device+0x8d0/0xb28 [ath9k]
[ 128.347324] [c7ffbd20] [c9173cf4]
ieee80211_sta_ps_deliver_wakeup+0xa4/0x1e4 [mac80211]
[ 128.355365] [c7ffbd50] [c91a3f74]
ieee80211_mps_sta_status_update+0xe4/0x158 [mac80211]
[ 128.363403] [c7ffbd70] [c9186f28]
ieee80211_sta_ps_transition+0xff0/0x34e4 [mac80211]
[ 128.371268] [c7ffbe00] [c91893b0]
ieee80211_sta_ps_transition+0x3478/0x34e4 [mac80211]
[ 128.379219] [c7ffbe40] [c9189ae8] ieee80211_rx+0x6cc/0x798 [mac80211]
[ 128.385678] [c7ffbea0] [c92b43c4] ath_rx_tasklet+0xe80/0xf74 [ath9k]
[ 128.392039] [c7ffbf70] [c92b1fdc] ath9k_tasklet+0xd0/0x114 [ath9k]
[ 128.398219] [c7ffbf90] [c0020b04] tasklet_action+0x88/0xe0
[ 128.403694] [c7ffbfb0] [c0021228] __do_softirq+0xa4/0x12c
[ 128.409088] [c7ffbff0] [c000cec8] call_do_softirq+0x14/0x24
[ 128.414655] [c73b7ee0] [c000550c] do_softirq+0x64/0xa4
[ 128.419783] [c73b7f00] [c0021464] irq_exit+0x48/0x74
[ 128.424739] [c73b7f10] [c0005424] do_IRQ+0x108/0x120
[ 128.429697] [c73b7f40] [c000ec5c] ret_from_except+0x0/0x14

Cedric Voncken

-----Message d'origine-----
De?: [email protected]
[mailto:[email protected]] De la part de Cedric VONCKEN
Envoy??: mardi 16 avril 2013 18:26
??: [email protected]
Objet?: ath9k null ppointer

I tried to use a mesh network with security (meshd/authsae).
I am using :
- openwrt with the latest mac80211 package from openwrt
- the Thomas Pedersen patch to add the authsae package in my
openwrt source tree
(Use the latest version, because I sent a patch in meshd this morning,
without it the HT mode should not correctly enable)
- AR9xx wirless card
- Kernel 3.3.8 on power PC (mpc 8314)

When I configure the meshd daemon to use the HT mode, I have a null pointer
in ath9k (That work correctly without HT mode).

In the file, drivers/net/wireless/ath/ath9k in the function
ath_tx_aggr_wakeup the ac pointer is null.

Do you know why this pointer can be null?

Cedric Voncken