mac80211: keep BHs disabled while calling drv_tx_wake_queue()

Drivers typically expect this, as it's the case for almost all cases
where this is called (i.e. from the TX path). Also, the code in mac80211
itself (if the driver calls ieee80211_tx_dequeue()) expects this as it
uses this_cpu_ptr() without additional protection.

This should fix various reports of the problem:
https://bugzilla.kernel.org/show_bug.cgi?id=204127
https://lore.kernel.org/linux-wireless/CAN5HydrWb3o_FE6A1XDnP1E+xS66d5kiEuhHfiGKkLNQokx13Q@mail.gmail.com/
https://lore.kernel.org/lkml/nycvar.YFH.7.76.1909111238470.473@cbobk.fhfr.pm/

Cc: stable@vger.kernel.org
Reported-and-tested-by: Jiri Kosina <jkosina@suse.cz>
Reported-by: Aaron Hill <aa1ronham@gmail.com>
Reported-by: Lukas Redlinger <rel+kernel@agilox.net>
Reported-by: Oleksii Shevchuk <alxchk@gmail.com>
Fixes: 21a5d4c3a45c ("mac80211: add stop/start logic for software TXQs")
Link: https://lore.kernel.org/r/1569928763-I3e8838c5ecad878e59d4a94eb069a90f6641461a@changeid
Reviewed-by: Toke Høiland-Jørgensen <toke@redhat.com>
Signed-off-by: Johannes Berg <johannes.berg@intel.com>

diff --git a/net/mac80211/util.c b/net/mac80211/util.c
index 051a02ddcb854d5dae0eb33e742129ffcf203848..32a7a53833c01d1ea760646440f54009ae9c4544 100644 (file)
--- a/net/mac80211/util.c
+++ b/net/mac80211/util.c
@@ -247,7 +247,8 @@ static void __ieee80211_wake_txqs(struct ieee80211_sub_if_data *sdata, int ac)
        struct sta_info *sta;
        int i;
 
-       spin_lock_bh(&fq->lock);
+       local_bh_disable();
+       spin_lock(&fq->lock);
 
        if (sdata->vif.type == NL80211_IFTYPE_AP)
                ps = &sdata->bss->ps;
@@ -273,9 +274,9 @@ static void __ieee80211_wake_txqs(struct ieee80211_sub_if_data *sdata, int ac)
                                                &txqi->flags))
                                continue;
 
-                       spin_unlock_bh(&fq->lock);
+                       spin_unlock(&fq->lock);
                        drv_wake_tx_queue(local, txqi);
-                       spin_lock_bh(&fq->lock);
+                       spin_lock(&fq->lock);
                }
        }
 
@@ -288,12 +289,14 @@ static void __ieee80211_wake_txqs(struct ieee80211_sub_if_data *sdata, int ac)
            (ps && atomic_read(&ps->num_sta_ps)) || ac != vif->txq->ac)
                goto out;
 
-       spin_unlock_bh(&fq->lock);
+       spin_unlock(&fq->lock);
 
        drv_wake_tx_queue(local, txqi);
+       local_bh_enable();
        return;
 out:
-       spin_unlock_bh(&fq->lock);
+       spin_unlock(&fq->lock);
+       local_bh_enable();
 }
 
 static void