Re: [TIP] BUG kmalloc-4096: Poison overwritten (ath5k_rx_skb_alloc)

[Bob Copeland <me@bobcopeland.com>]

On Wed, May 13, 2009 at 10:44:17PM +0100, Sitsofe Wheeler wrote:
> Could you repost the patches you wanted me to test with against the
> latest kernel?

This is too ugly to live, but I'd like to know if you can reproduce
with this patch.  If it still happens, then I guess it's back to
debugging patches.  I'd love to be able to replicate this here :(

diff --git a/drivers/net/wireless/ath5k/base.c b/drivers/net/wireless/ath5k/base.c
index a08bc8a..e01da34 100644
--- a/drivers/net/wireless/ath5k/base.c
+++ b/drivers/net/wireless/ath5k/base.c
@@ -1143,6 +1143,13 @@ struct sk_buff *ath5k_rx_skb_alloc(struct ath5k_softc *sc, dma_addr_t *skb_addr)
 }
 
 static int
+ath5k_rxbuf_requeue(struct ath5k_softc *sc, struct ath5k_buf *bf)
+{
+	list_move_tail(&bf->list, &sc->rxbuf);
+	return ath5k_rxbuf_setup(sc, bf);
+}
+
+static int
 ath5k_rxbuf_setup(struct ath5k_softc *sc, struct ath5k_buf *bf)
 {
 	struct ath5k_hw *ah = sc->ah;
@@ -1751,7 +1758,7 @@ ath5k_tasklet_rx(unsigned long data)
 		goto unlock;
 	}
 	bf_last = list_entry(sc->rxbuf.prev, struct ath5k_buf, list);
-	do {
+	for (;;) {
 		rxs.flag = 0;
 
 		bf = list_first_entry(&sc->rxbuf, struct ath5k_buf, list);
@@ -1904,13 +1911,18 @@ accept:
 		if (sc->opmode == NL80211_IFTYPE_ADHOC)
 			ath5k_check_ibss_tsf(sc, skb, &rxs);
 
-		__ieee80211_rx(sc->hw, skb, &rxs);
-
 		bf->skb = next_skb;
 		bf->skbaddr = next_skb_addr;
+		if (ath5k_rxbuf_requeue(sc, bf))
+			break;
+
+		__ieee80211_rx(sc->hw, skb, &rxs);
+		continue;
 next:
-		list_move_tail(&bf->list, &sc->rxbuf);
-	} while (ath5k_rxbuf_setup(sc, bf) == 0);
+		if (ath5k_rxbuf_requeue(sc, bf))
+			break;
+	}
+
 unlock:
 	spin_unlock(&sc->rxbuflock);
 }

-- 
Bob Copeland %% www.bobcopeland.com