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ath9k: Fix leak in tx descriptor

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When we reclaim the tx desc, we always assume that the
last desc is a holding desc, which is not true, and skip it.
If the tx queue is drained during channel change, internal
reset and etc, the last descriptor may not be the holding
descriptor and we fail to reclaim them. This results in the
following two issues.

1. Tx stuck - We drop all the frames coming from upper layer
due to shortage in tx desc.

2. Crash - If we fail to reclaim a tx descriptor, we miss to
update the tx BA window with the seq number of the frame
associated to that desc, which, at some point, result in
the following crash due to an assert failure in ath_tx_addto_baw().

This patch fixes these two issues.

 kernel BUG at ../drivers/net/wireless/ath/ath9k/xmit.c:180!
[155064.304164] invalid opcode: 0000 [#1] SMP
 Call Trace:
  [<fbc6d83b>] ? ath9k_tx+0xeb/0x160 [ath9k]
  [<fbbc9591>]  ipv6? __ieee80211_tx+0x41/0x120 [mac80211]
  [<fbbcb5ae>] ?  aes_i586ieee80211_master_start_xmit+0x28e/0x560 [mac80211]
  [<c037e501>]  aes_generic? _spin_lock_irqsave+0x31/0x40
  [<c02f347b>] ? dev_hard_start_xmit+0x16b/0x1c0
  [<c03058b5>] ? __qdisc_run+0x1b5/0x200
  [<fbbcda5a>] ?  af_packetieee80211_select_queue+0xa/0x100 [mac80211]
  [<c02f53b7>] ?  i915dev_queue_xmit+0x2e7/0x3f0
  [<fbbc9b49>] ? ieee80211_subif_start_xmit+0x369/0x7a0 [mac80211]
  [<c031bc35>] ? ip_output+0x55/0xb0
  [<c02e0188>] ? show_memcpy_count+0x18/0x60
  [<c02eb186>] ? __kfree_skb+0x36/0x90
  [<c02f2202>] ?  binfmt_miscdev_queue_xmit_nit+0xd2/0x110
  [<c02f347b>] ? dev_hard_start_xmit+0x16b/0x1c0
  [<c03058b5>] ? __qdisc_run+0x1b5/0x200
  [<c033bca7>] ?  scoarp_create+0x57/0x2a0
  [<c02f53b7>] ?  bridgedev_queue_xmit+0x2e7/0x3f0
  [<c03034a0>] ? eth_header+0x0/0xc0
  [<c033b95f>]  stp? arp_xmit+0x5f/0x70
  [<c033bf4f>] ? arp_send+0x5f/0x70
  [<c033c8f5>]  bnep? arp_solicit+0x105/0x210
  [<c02fa5aa>] ? neigh_timer_handler+0x19a/0x390
  [<c013bf88>] ? run_timer_softirq+0x138/0x210
  [<c02fa410>] ?  ppdevneigh_timer_handler+0x0/0x390
  [<c02fa410>] ? neigh_timer_handler+0x0/0x390

Signed-off-by: Vasanthakumar Thiagarajan <vasanth@atheros.com>
Signed-off-by: John W. Linville <linville@tuxdriver.com>
This commit is contained in:
Vasanthakumar Thiagarajan 2009-06-24 18:58:47 +05:30 committed by John W. Linville
parent fd4973c56f
commit cbfe89c67b
1 changed files with 8 additions and 1 deletions
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9
drivers/net/wireless/ath/ath9k/xmit.c
View file

@ -355,7 +355,14 @@ static void ath_tx_complete_aggr(struct ath_softc *sc, struct ath_txq *txq,
}
if (bf_next == NULL) {
INIT_LIST_HEAD(&bf_head);
/*
* Make sure the last desc is reclaimed if it
* not a holding desc.
*/
if (!bf_last->bf_stale)
list_move_tail(&bf->list, &bf_head);
else
INIT_LIST_HEAD(&bf_head);
} else {
ASSERT(!list_empty(bf_q));
list_move_tail(&bf->list, &bf_head);