wifi: mac80211: do not wake queues on a vif that is being stopped

When a vif is being removed and sdata->bss is cleared, __ieee80211_wake_txqs
can still be called on it, which crashes as soon as sdata->bss is being
dereferenced.
To fix this properly, check for SDATA_STATE_RUNNING before waking queues,
and take the fq lock when setting it (to ensure that __ieee80211_wake_txqs
observes the change when running on a different CPU)

Signed-off-by: Felix Fietkau <nbd@nbd.name>
Acked-by: Toke Høiland-Jørgensen <toke@kernel.org>
Link: https://lore.kernel.org/r/20220531190824.60019-1-nbd@nbd.name
Signed-off-by: Johannes Berg <johannes.berg@intel.com>

diff --git a/net/mac80211/iface.c b/net/mac80211/iface.c
index 4153147..15a73b7 100644 (file)
--- a/net/mac80211/iface.c
+++ b/net/mac80211/iface.c
@@ -377,7 +377,9 @@ static void ieee80211_do_stop(struct ieee80211_sub_if_data *sdata, bool going_do
        bool cancel_scan;
        struct cfg80211_nan_func *func;
 
+       spin_lock_bh(&local->fq.lock);
        clear_bit(SDATA_STATE_RUNNING, &sdata->state);
+       spin_unlock_bh(&local->fq.lock);
 
        cancel_scan = rcu_access_pointer(local->scan_sdata) == sdata;
        if (cancel_scan)

diff --git a/net/mac80211/util.c b/net/mac80211/util.c
index 1e26b52..dad42d4 100644 (file)
--- a/net/mac80211/util.c
+++ b/net/mac80211/util.c
@@ -301,6 +301,9 @@ static void __ieee80211_wake_txqs(struct ieee80211_sub_if_data *sdata, int ac)
        local_bh_disable();
        spin_lock(&fq->lock);
 
+       if (!test_bit(SDATA_STATE_RUNNING, &sdata->state))
+               goto out;
+
        if (sdata->vif.type == NL80211_IFTYPE_AP)
                ps = &sdata->bss->ps;