From 33df033b73365487c5bb5a58b77aed04d4ca6ac1 Mon Sep 17 00:00:00 2001 From: Felix Fietkau Date: Sun, 27 Mar 2022 00:05:49 +0100 Subject: [PATCH] mac80211: add a bug fix for a rare crash Signed-off-by: Felix Fietkau (cherry picked from commit 9a93b62f315ad4c9f021c414ed80ba337ab4a01e) --- ...wake-queues-on-a-vif-that-is-being-s.patch | 38 +++++++++++++++++++ 1 file changed, 38 insertions(+) create mode 100644 package/kernel/mac80211/patches/subsys/328-mac80211-do-not-wake-queues-on-a-vif-that-is-being-s.patch diff --git a/package/kernel/mac80211/patches/subsys/328-mac80211-do-not-wake-queues-on-a-vif-that-is-being-s.patch b/package/kernel/mac80211/patches/subsys/328-mac80211-do-not-wake-queues-on-a-vif-that-is-being-s.patch new file mode 100644 index 0000000000..f0150ddef0 --- /dev/null +++ b/package/kernel/mac80211/patches/subsys/328-mac80211-do-not-wake-queues-on-a-vif-that-is-being-s.patch @@ -0,0 +1,38 @@ +From: Felix Fietkau +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 +--- + +--- 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; + -- 2.30.2