From: Felix Fietkau Date: Thu, 25 Oct 2012 22:31:11 +0000 (+0200) Subject: ath9k: fix stale pointers potentially causing access to free'd skbs X-Git-Tag: v3.0.52~40 X-Git-Url: https://git.karo-electronics.de/?a=commitdiff_plain;h=a699cd395b19aa262fbffcbe79aec1c57238e489;p=karo-tx-linux.git ath9k: fix stale pointers potentially causing access to free'd skbs 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 Signed-off-by: John W. Linville Signed-off-by: Greg Kroah-Hartman --- diff --git a/drivers/net/wireless/ath/ath9k/xmit.c b/drivers/net/wireless/ath/ath9k/xmit.c index 33443bcaa8d9..6f6f1002e5db 100644 --- a/drivers/net/wireless/ath/ath9k/xmit.c +++ b/drivers/net/wireless/ath/ath9k/xmit.c @@ -272,6 +272,7 @@ 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); @@ -1488,6 +1489,7 @@ static void ath_tx_send_normal(struct ath_softc *sc, struct ath_txq *txq, if (tid) INCR(tid->seq_start, IEEE80211_SEQ_MAX); + bf->bf_next = NULL; bf->bf_lastbf = bf; fi = get_frame_info(bf->bf_mpdu); ath_buf_set_rate(sc, bf, fi->framelen);