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From:   Greg Kroah-Hartman <gregkh@linuxfoundation.org>
To:     linux-kernel@vger.kernel.org
Cc:     Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
        stable@vger.kernel.org, Aaron Hill <aa1ronham@gmail.com>,
        Lukas Redlinger <rel+kernel@agilox.net>,
        Oleksii Shevchuk <alxchk@gmail.com>,
        =?UTF-8?q?Toke=20H=C3=B8iland-J=C3=B8rgensen?= <toke@redhat.com>,
        Johannes Berg <johannes.berg@intel.com>,
        Jiri Kosina <jkosina@suse.cz>
Subject: [PATCH 5.3 073/148] mac80211: keep BHs disabled while calling drv_tx_wake_queue()
Date:   Thu, 10 Oct 2019 10:35:34 +0200
Message-Id: <20191010083615.810908484@linuxfoundation.org>
In-Reply-To: <20191010083609.660878383@linuxfoundation.org>
References: <20191010083609.660878383@linuxfoundation.org>
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From: Johannes Berg <johannes.berg@intel.com>

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: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

---
 net/mac80211/util.c |   13 ++++++++-----
 1 file changed, 8 insertions(+), 5 deletions(-)

--- a/net/mac80211/util.c
+++ b/net/mac80211/util.c
@@ -247,7 +247,8 @@ static void __ieee80211_wake_txqs(struct
 	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
 						&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
 	    (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