2011-03-21 12:57:29

by Mohammed Shafi Shajakhan

[permalink] [raw]
Subject: [PATCH] ath9k: Fix kernel panic in AR2427

From: Mohammed Shafi Shajakhan <[email protected]>

Kernel panic occurs just after AR2427 establishes connection with AP.
Unless aggregation is enabled we don't initialize the TID structure.
Thus accesing the elements of the TID structure when aggregation is
disabled, leads to NULL pointer dereferencing.

[ 191.320358] Call Trace:
[ 191.320364] [<fd250ea7>] ? ath9k_tx+0xa7/0x200 [ath9k]
[ 191.320376] [<fd1ec7fc>] ? __ieee80211_tx+0x5c/0x1e0 [mac80211]
[ 191.320386] [<fd1edd2b>] ? ieee80211_tx+0x7b/0x90 [mac80211]
[ 191.320395] [<fd1edddd>] ? ieee80211_xmit+0x9d/0x1d0 [mac80211]
[ 191.320401] [<c014218f>] ? wake_up_state+0xf/0x20
[ 191.320405] [<c015dbc8>] ? signal_wake_up+0x28/0x40
[ 191.320410] [<c012a578>] ? default_spin_lock_flags+0x8/0x10
[ 191.320420] [<fd1ee308>] ? ieee80211_subif_start_xmit+0x2e8/0x7c0
[mac80211]
[ 191.320425] [<c058f905>] ? do_page_fault+0x295/0x3a0
[ 191.320431] [<c04c4a3d>] ? dev_hard_start_xmit+0x1ad/0x210
[ 191.320436] [<c04d96b5>] ? sch_direct_xmit+0x105/0x170
[ 191.320445] [<fd1f161a>] ? get_sta_flags+0x2a/0x40 [mac80211]
[ 191.320449] [<c04c780f>] ? dev_queue_xmit+0x37f/0x4b0
[ 191.320452] [<c04d75b0>] ? eth_header+0x0/0xb0
[ 191.320456] [<c04cc479>] ? neigh_resolve_output+0xe9/0x310
[ 191.320461] [<c053d295>] ? ip6_output_finish+0xa5/0x110
[ 191.320464] [<c053e354>] ? ip6_output2+0x134/0x250
[ 191.320468] [<c053f7dd>] ? ip6_output+0x6d/0x100
[ 191.320471] [<c0559665>] ? mld_sendpack+0x395/0x3e0
[ 191.320475] [<c0557f81>] ? add_grhead+0x31/0xa0
[ 191.320478] [<c055a83c>] ? mld_send_cr+0x1bc/0x2b0
[ 191.320482] [<c01535d9>] ? irq_exit+0x39/0x70
[ 191.320485] [<c055a940>] ? mld_ifc_timer_expire+0x10/0x40
[ 191.320489] [<c015b92e>] ? run_timer_softirq+0x13e/0x2c0
[ 191.320493] [<c0103a30>] ? common_interrupt+0x30/0x40
[ 191.320498] [<c055a930>] ? mld_ifc_timer_expire+0x0/0x40
[ 191.320502] [<c0153358>] ? __do_softirq+0x98/0x1b0
[ 191.320506] [<c01534b5>] ? do_softirq+0x45/0x50
[ 191.320509] [<c0153605>] ? irq_exit+0x65/0x70
[ 191.320513] [<c05917dc>] ? smp_apic_timer_interrupt+0x5c/0x8b
[ 191.320516] [<c0103df1>] ? apic_timer_interrupt+0x31/0x40
[ 191.320521] [<c016007b>] ? k_getrusage+0x12b/0x2f0
[ 191.320525] [<c039e384>] ? acpi_idle_enter_simple+0x117/0x148
[ 191.320529] [<c04a20da>] ? cpuidle_idle_call+0x7a/0x100
[ 191.320532] [<c01021d4>] ? cpu_idle+0x94/0xd0
[ 191.320536] [<c057ab88>] ? rest_init+0x58/0x60
[ 191.320541] [<c07a58ec>] ? start_kernel+0x351/0x357
[ 191.320544] [<c07a53c7>] ? unknown_bootoption+0x0/0x19e
[ 191.320548] [<c07a50aa>] ? i386_start_kernel+0xaa/0xb1
[ 191.320550] Code: 03 66 3d 00 03 0f 84 7c 02 00 00 83 c3 18 0f b6 03
8b 4d e0 89 c3 83 e3 0f 6b c3 48 89 5d d8 8d 04 06 8d 50 0c 89 55 d0 8b
40 20 <8b> 00 3b 01 0f 85 8e 02 00 00 f6 47 20 40 0f 84 29 ff ff ff 8b
[ 191.320634] EIP: [<fd2586d4>] ath_tx_start+0x474/0x770 [ath9k] SS:ESP
0068:c0761a90
[ 191.320642] CR2: 0000000000000000
[ 191.320647] ---[ end trace 9296ef23b9076ece ]---
[ 191.320650] Kernel panic - not syncing: Fatal exception in interrupt

Cc: [email protected]
Signed-off-by: Mohammed Shafi Shajakhan <[email protected]>
---
drivers/net/wireless/ath/ath9k/xmit.c | 4 ++--
1 files changed, 2 insertions(+), 2 deletions(-)

diff --git a/drivers/net/wireless/ath/ath9k/xmit.c b/drivers/net/wireless/ath/ath9k/xmit.c
index ef22096..26734e5 100644
--- a/drivers/net/wireless/ath/ath9k/xmit.c
+++ b/drivers/net/wireless/ath/ath9k/xmit.c
@@ -1725,8 +1725,8 @@ static void ath_tx_start_dma(struct ath_softc *sc, struct ath_buf *bf,
u8 tidno;

spin_lock_bh(&txctl->txq->axq_lock);
-
- if (ieee80211_is_data_qos(hdr->frame_control) && txctl->an) {
+ if ((sc->sc_flags & SC_OP_TXAGGR) && txctl->an &&
+ ieee80211_is_data_qos(hdr->frame_control)) {
tidno = ieee80211_get_qos_ctl(hdr)[0] &
IEEE80211_QOS_CTL_TID_MASK;
tid = ATH_AN_2_TID(txctl->an, tidno);
--
1.7.0.4