[PATCH 5.19 016/101] wifi: mac80211: ensure vif queues are operational after start

From: Greg Kroah-Hartman
Date: Mon Oct 03 2022 - 03:13:24 EST

From: Alexander Wetzel <alexander@xxxxxxxxxxxxxx>

commit 527008e5e87600a389feb8a57042c928ecca195d upstream.

Make sure local->queue_stop_reasons and vif.txqs_stopped stay in sync.

When a new vif is created the queues may end up in an inconsistent state
and be inoperable:
Communication not using iTXQ will work, allowing to e.g. complete the
association. But the 4-way handshake will time out. The sta will not
send out any skbs queued in iTXQs.

All normal attempts to start the queues will fail when reaching this
local->queue_stop_reasons will have marked all queues as operational but
vif.txqs_stopped will still be set, creating an inconsistent internal

In reality this seems to be race between the mac80211 function
ieee80211_do_open() setting SDATA_STATE_RUNNING and the wake_txqs_tasklet:
Depending on the driver and the timing the queues may end up to be
operational or not.

Cc: stable@xxxxxxxxxxxxxxx
Fixes: f856373e2f31 ("wifi: mac80211: do not wake queues on a vif that is being stopped")
Signed-off-by: Alexander Wetzel <alexander@xxxxxxxxxxxxxx>
Acked-by: Felix Fietkau <nbd@xxxxxxxx>
Link: https://lore.kernel.org/r/20220915130946.302803-1-alexander@xxxxxxxxxxxxxx
Signed-off-by: Johannes Berg <johannes.berg@xxxxxxxxx>
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>
net/mac80211/util.c | 4 ++--
1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/net/mac80211/util.c b/net/mac80211/util.c
index 53826c663723..efcefb2dd882 100644
--- a/net/mac80211/util.c
+++ b/net/mac80211/util.c
@@ -301,14 +301,14 @@ static void __ieee80211_wake_txqs(struct ieee80211_sub_if_data *sdata, int ac)

+ sdata->vif.txqs_stopped[ac] = false;
if (!test_bit(SDATA_STATE_RUNNING, &sdata->state))
goto out;

if (sdata->vif.type == NL80211_IFTYPE_AP)
ps = &sdata->bss->ps;

- sdata->vif.txqs_stopped[ac] = false;
list_for_each_entry_rcu(sta, &local->sta_list, list) {
if (sdata != sta->sdata)