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Commit 8c6e3093 authored by Felix Fietkau's avatar Felix Fietkau Committed by John W. Linville
Browse files

ath9k: fix stale pointers potentially causing access to free'd skbs 



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: default avatarFelix Fietkau <nbd@openwrt.org>
Cc: stable@vger.kernel.org
Signed-off-by: default avatarJohn W. Linville <linville@tuxdriver.com>
parent efec22b4

drivers/net/wireless/ath/ath9k/xmit.c

+2 −0
Original line number Diff line number Diff line
@@ -312,6 +312,7 @@ static struct ath_buf *ath_tx_get_buffer(struct ath_softc *sc) 
	}



	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);
@@ -1774,6 +1775,7 @@ static void ath_tx_send_normal(struct ath_softc *sc, struct ath_txq *txq, 
	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);