From 271f1e65ff38f18aa440fec17c759e70a6adfa4e Mon Sep 17 00:00:00 2001 From: Daniel Mack Date: Tue, 3 Apr 2018 18:51:53 +0200 Subject: [PATCH] wcn36xx: don't keep reference to skb if transmission failed When wcn36xx_dxe_tx_frame() fails to transmit the TX frame, the driver will call into ieee80211_free_txskb() for the skb in flight, so it'll no longer be valid. Hence, we shouldn't keep a reference to it in ctl->skb. Also, if the skb has IEEE80211_TX_CTL_REQ_TX_STATUS set, a pointer to it will currently remain in wcn->tx_ack_skb, which will potentially lead to a crash if accessed later. Fix this by checking the return value of wcn36xx_dxe_tx_frame(), and nullify wcn->tx_ack_skb again in case of errors. Move the assignment of ctl->skb in wcn36xx_dxe_tx_frame() so it only happens when the transmission is successful. Signed-off-by: Daniel Mack Signed-off-by: Kalle Valo --- drivers/net/wireless/ath/wcn36xx/dxe.c | 6 +++--- drivers/net/wireless/ath/wcn36xx/txrx.c | 15 ++++++++++++++- 2 files changed, 17 insertions(+), 4 deletions(-) diff --git a/drivers/net/wireless/ath/wcn36xx/dxe.c b/drivers/net/wireless/ath/wcn36xx/dxe.c index 405d350..2cedb5a 100644 --- a/drivers/net/wireless/ath/wcn36xx/dxe.c +++ b/drivers/net/wireless/ath/wcn36xx/dxe.c @@ -693,7 +693,6 @@ int wcn36xx_dxe_tx_frame(struct wcn36xx *wcn, /* Set source address of the SKB we send */ ctl = ctl->next; - ctl->skb = skb; desc = ctl->desc; if (ctl->bd_cpu_addr) { wcn36xx_err("bd_cpu_addr cannot be NULL for skb DXE\n"); @@ -702,8 +701,8 @@ int wcn36xx_dxe_tx_frame(struct wcn36xx *wcn, } desc->src_addr_l = dma_map_single(wcn->dev, - ctl->skb->data, - ctl->skb->len, + skb->data, + skb->len, DMA_TO_DEVICE); if (dma_mapping_error(wcn->dev, desc->src_addr_l)) { dev_err(wcn->dev, "unable to DMA map src_addr_l\n"); @@ -711,6 +710,7 @@ int wcn36xx_dxe_tx_frame(struct wcn36xx *wcn, goto unlock; } + ctl->skb = skb; desc->dst_addr_l = ch->dxe_wq; desc->fr_len = ctl->skb->len; diff --git a/drivers/net/wireless/ath/wcn36xx/txrx.c b/drivers/net/wireless/ath/wcn36xx/txrx.c index b1768ed..a690237 100644 --- a/drivers/net/wireless/ath/wcn36xx/txrx.c +++ b/drivers/net/wireless/ath/wcn36xx/txrx.c @@ -273,6 +273,7 @@ int wcn36xx_start_tx(struct wcn36xx *wcn, bool bcast = is_broadcast_ether_addr(hdr->addr1) || is_multicast_ether_addr(hdr->addr1); struct wcn36xx_tx_bd bd; + int ret; memset(&bd, 0, sizeof(bd)); @@ -317,5 +318,17 @@ int wcn36xx_start_tx(struct wcn36xx *wcn, buff_to_be((u32 *)&bd, sizeof(bd)/sizeof(u32)); bd.tx_bd_sign = 0xbdbdbdbd; - return wcn36xx_dxe_tx_frame(wcn, vif_priv, &bd, skb, is_low); + ret = wcn36xx_dxe_tx_frame(wcn, vif_priv, &bd, skb, is_low); + if (ret && bd.tx_comp) { + /* If the skb has not been transmitted, + * don't keep a reference to it. + */ + spin_lock_irqsave(&wcn->dxe_lock, flags); + wcn->tx_ack_skb = NULL; + spin_unlock_irqrestore(&wcn->dxe_lock, flags); + + ieee80211_wake_queues(wcn->hw); + } + + return ret; } -- 2.7.4