release/5.2.22/mac80211-keep-BHs-disabled-while-calling-drv_tx_wake.patch

From 5b7bb0069626aa4ee05ef470d8dc46b1f882f463 Mon Sep 17 00:00:00 2001
From: Johannes Berg <johannes.berg@intel.com>
Date: Tue, 1 Oct 2019 13:19:23 +0200
Subject: [PATCH] mac80211: keep BHs disabled while calling drv_tx_wake_queue()
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commit d8dec42b5c2d2b273bc30b0e073cfbe832d69902 upstream.

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>
Signed-off-by: Paul Gortmaker <paul.gortmaker@windriver.com>

diff --git a/net/mac80211/util.c b/net/mac80211/util.c
index ad1e58184c4e..21212faec6d0 100644
--- 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
-- 
2.7.4