wifi: mac80211: ensure vif queues are operational after start

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
state.
local->queue_stop_reasons will have marked all queues as operational but
vif.txqs_stopped will still be set, creating an inconsistent internal
state.

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@vger.kernel.org
Fixes: f856373e2f31 ("wifi: mac80211: do not wake queues on a vif that is being stopped")
Signed-off-by: Alexander Wetzel <alexander@wetzel-home.de>
Acked-by: Felix Fietkau <nbd@nbd.name>
Link: https://lore.kernel.org/r/20220915130946.302803-1-alexander@wetzel-home.de
Signed-off-by: Johannes Berg <johannes.berg@intel.com>

diff --git a/net/mac80211/util.c b/net/mac80211/util.c
index 53826c6..efcefb2 100644 (file)
--- 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)
        local_bh_disable();
        spin_lock(&fq->lock);
 
+       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)
                        continue;