[ 04/57] ath9k: fix stale pointers potentially causing access to freed skbs
From: Greg Kroah-Hartman
Date: Wed Nov 14 2012 - 23:23:26 EST
3.4-stable review patch. If anyone has any objections, please let me know.
------------------
From: Felix Fietkau <nbd@xxxxxxxxxxx>
commit 8c6e30936a7893a85f6222084f0f26aceb81137a upstream.
bf->bf_next is only while buffers are chained as part of an A-MPDU
in the tx queue. When a tid queue is flushed (e.g. on tearing down
an aggregation session), frames can be enqueued again as normal
transmission, without bf_next being cleared. This can lead to the
old pointer being dereferenced again later.
This patch might fix crashes and "Failed to stop TX DMA!" messages.
Signed-off-by: Felix Fietkau <nbd@xxxxxxxxxxx>
Signed-off-by: John W. Linville <linville@xxxxxxxxxxxxx>
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>
---
drivers/net/wireless/ath/ath9k/xmit.c | 2 ++
1 file changed, 2 insertions(+)
--- a/drivers/net/wireless/ath/ath9k/xmit.c
+++ b/drivers/net/wireless/ath/ath9k/xmit.c
@@ -337,6 +337,7 @@ static struct ath_buf *ath_tx_get_buffer
}
bf = list_first_entry(&sc->tx.txbuf, struct ath_buf, list);
+ bf->bf_next = NULL;
list_del(&bf->list);
spin_unlock_bh(&sc->tx.txbuflock);
@@ -1760,6 +1761,7 @@ static void ath_tx_send_normal(struct at
list_add_tail(&bf->list, &bf_head);
bf->bf_state.bf_type = 0;
+ bf->bf_next = NULL;
bf->bf_lastbf = bf;
ath_tx_fill_desc(sc, bf, txq, fi->framelen);
ath_tx_txqaddbuf(sc, txq, &bf_head, false);
--
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