2022-09-18 19:49:28

by Hans de Goede

[permalink] [raw]
Subject: [PATCH] mac80211: Fix regression caused by 'enable QoS support for nl80211 ctrl port'

Commit 10cb8e617560 ("mac80211: enable QoS support for nl80211 ctrl port")
changed ieee80211_tx_control_port() to aways call
__ieee80211_select_queue() without checking local->hw.queues.

__ieee80211_select_queue() returns a queue-id between 0 and 3, which means
that now ieee80211_tx_control_port() may end up setting the queue-mapping
for a skb to a value higher then local->hw.queues if local->hw.queues
is less then 4.

Specifically this is a problem for ralink rt2500-pci cards where
local->hw.queues is 2. There this causes rt2x00queue_get_tx_queue() to
return NULL and the following error to be logged: "ieee80211 phy0:
rt2x00mac_tx: Error - Attempt to send packet over invalid queue 2",
after which association with the AP fails.

Other callers of __ieee80211_select_queue() skip calling it when
local->hw.queues < IEEE80211_NUM_ACS, add the same check to
ieee80211_tx_control_port(). This fixes ralink rt2500-pci and
similar cards when less then 4 tx-queues no longer working.

Fixes: 10cb8e617560 ("mac80211: enable QoS support for nl80211 ctrl port")
Cc: Markus Theil <[email protected]>
Suggested-by: Stanislaw Gruszka <[email protected]>
Signed-off-by: Hans de Goede <[email protected]>
---
net/mac80211/tx.c | 4 ++++
1 file changed, 4 insertions(+)

diff --git a/net/mac80211/tx.c b/net/mac80211/tx.c
index bf7fe6cd9dfc..13249e97a069 100644
--- a/net/mac80211/tx.c
+++ b/net/mac80211/tx.c
@@ -5878,6 +5878,9 @@ int ieee80211_tx_control_port(struct wiphy *wiphy, struct net_device *dev,
skb_reset_network_header(skb);
skb_reset_mac_header(skb);

+ if (local->hw.queues < IEEE80211_NUM_ACS)
+ goto start_xmit;
+
/* update QoS header to prioritize control port frames if possible,
* priorization also happens for control port frames send over
* AF_PACKET
@@ -5905,6 +5908,7 @@ int ieee80211_tx_control_port(struct wiphy *wiphy, struct net_device *dev,
}
rcu_read_unlock();

+start_xmit:
/* mutex lock is only needed for incrementing the cookie counter */
mutex_lock(&local->mtx);

--
2.37.3