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From: Felix Fietkau <nbd@nbd.name>
Date: Sat, 26 Mar 2022 23:58:35 +0100
Subject: [PATCH] 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>
---
--- a/net/mac80211/iface.c
+++ b/net/mac80211/iface.c
@@ -377,7 +377,9 @@ static void ieee80211_do_stop(struct iee
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)
--- a/net/mac80211/util.c
+++ b/net/mac80211/util.c
@@ -301,6 +301,9 @@ static void __ieee80211_wake_txqs(struct
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;
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