Using not existing queues can panic the kernel with rtl8180/rtl8185 cards. Ignore the skb priority for those cards, they only have one tx queue.
Cc: stable@vger.kernel.org Reported-by: pa@panix.com Tested-by: pa@panix.com Signed-off-by: Alexander Wetzel alexander@wetzel-home.de ---
Pierre Asselin (pa@panix.com) reported a kernel crash in the Gentoo forum: https://forums.gentoo.org/viewtopic-t-1147832-postdays-0-postorder-asc-start... He also confirmed that this patch fixes the issue.
In summary this happened: After updating wpa_supplicant from 2.9 to 2.10 the kernel crashed with a "divide error: 0000" when connecting to an AP. Control port tx now tries to use IEEE80211_AC_VO for the priority, which wpa_supplicants starts to use in 2.10.
Since only the rtl8187se part of the driver supports QoS, the priority of the skb is set to IEEE80211_AC_BE (2) by mac80211 for rtl8180/rtl8185 cards.
rtl8180 is then unconditionally reading out the priority and finally crashes on drivers/net/wireless/realtek/rtl818x/rtl8180/dev.c line 544 without this patch: idx = (ring->idx + skb_queue_len(&ring->queue)) % ring->entries
"ring->entries" is zero for rtl8180/rtl8185 cards, tx_ring[2] never got initialized.
drivers/net/wireless/realtek/rtl818x/rtl8180/dev.c | 8 ++++++-- 1 file changed, 6 insertions(+), 2 deletions(-)
diff --git a/drivers/net/wireless/realtek/rtl818x/rtl8180/dev.c b/drivers/net/wireless/realtek/rtl818x/rtl8180/dev.c index 2477e18c7cae..025619cd14e8 100644 --- a/drivers/net/wireless/realtek/rtl818x/rtl8180/dev.c +++ b/drivers/net/wireless/realtek/rtl818x/rtl8180/dev.c @@ -460,8 +460,10 @@ static void rtl8180_tx(struct ieee80211_hw *dev, struct rtl8180_priv *priv = dev->priv; struct rtl8180_tx_ring *ring; struct rtl8180_tx_desc *entry; + unsigned int prio = 0; unsigned long flags; - unsigned int idx, prio, hw_prio; + unsigned int idx, hw_prio; + dma_addr_t mapping; u32 tx_flags; u8 rc_flags; @@ -470,7 +472,9 @@ static void rtl8180_tx(struct ieee80211_hw *dev, /* do arithmetic and then convert to le16 */ u16 frame_duration = 0;
- prio = skb_get_queue_mapping(skb); + /* rtl8180/rtl8185 only has one useable tx queue */ + if (dev->queues > IEEE80211_AC_BK) + prio = skb_get_queue_mapping(skb); ring = &priv->tx_ring[prio];
mapping = dma_map_single(&priv->pdev->dev, skb->data, skb->len,