openwrt/package/kernel/mac80211/patches/subsys/342-mac80211-Ensure-vif-queues-are-operational-after-sta.patch
Felix Fietkau 8b06e06832 mac80211: merge pending fixes for tx queueing issues
Fixes a potential deadlock and a tx queue hang on STA assoc

Signed-off-by: Felix Fietkau <nbd@nbd.name>
2022-09-15 16:43:04 +02:00

48 lines
1.6 KiB
Diff

From: Alexander Wetzel <alexander@wetzel-home.de>
Date: Thu, 15 Sep 2022 15:09:46 +0200
Subject: [PATCH] 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>
---
--- a/net/mac80211/util.c
+++ b/net/mac80211/util.c
@@ -301,14 +301,14 @@ static void __ieee80211_wake_txqs(struct
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;