On 10/11/2010 11:10 PM, Luis R. Rodriguez wrote:
On Mon, Oct 11, 2010 at 8:27 PM, Ben Greear<greearb@xxxxxxxxxxxxxxx> wrote:
Another thing I was thinking about: Maybe the queue of skbs and dma
addresses
in ath9k is getting corrupted by multiple VIFs trying to write at once?
Maybe
some locking is needed in the xmit path?
That was my second hunch. My first shot was to use spin_lock_irqsave()
over the the uses of the rxbuf list and that seemed to help but I
still managed to get a poison eventually. My next item to check for is
of the permissibility of creating too much pressure to the point we
end up looping over the rxbuf list and race against mac80211 free'ing
a buffer. Will test that tomorrow if nothing else comes up creeping my
priority queue.
This code looks weird to me. One of the paprd branches
deletes the skb, the other doesn't appear to. Neither
null out bf->bf_mpdu, which would appear to leave a dangling
pointer in at least the dev_kfree_skb_any() branch.
ath_tx_complete frees it's skb in all cases, so another
bf->bf_mpdu dangling pointer issue.
Maybe at the least we should null out bf->bf_mpdu when
skb is consumed?
static void ath_tx_complete_buf(struct ath_softc *sc, struct ath_buf *bf,
struct ath_txq *txq, struct list_head *bf_q,
struct ath_tx_status *ts, int txok, int sendbar)
{
struct sk_buff *skb = bf->bf_mpdu;
unsigned long flags;
int tx_flags = 0;
if (sendbar)
tx_flags = ATH_TX_BAR;
if (!txok) {
tx_flags |= ATH_TX_ERROR;
if (bf_isxretried(bf))
tx_flags |= ATH_TX_XRETRY;
}
dma_unmap_single(sc->dev, bf->bf_dmacontext, skb->len, DMA_TO_DEVICE);
if (bf->bf_state.bfs_paprd) {
if (time_after(jiffies,
bf->bf_state.bfs_paprd_timestamp +
msecs_to_jiffies(ATH_PAPRD_TIMEOUT)))
dev_kfree_skb_any(skb);
else
complete(&sc->paprd_complete);
} else {
ath_tx_complete(sc, skb, bf->aphy, tx_flags);
ath_debug_stat_tx(sc, txq, bf, ts);
}
Luis
--
Ben Greear <greearb@xxxxxxxxxxxxxxx>
Candela Technologies Inc http://www.candelatech.com
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