From f1267cf3c01b12e0f843fb6a7450a7f0b2efab8a Mon Sep 17 00:00:00 2001
From: Bhagavathi Perumal S <bperumal@codeaurora.org>
Date: Tue, 16 Apr 2019 12:54:40 +0530
Subject: [PATCH] mac80211: Fix kernel panic due to use of txq after free
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Git-commit: f1267cf3c01b12e0f843fb6a7450a7f0b2efab8a
Patch-mainline: v5.1
References: bsc#1051510

The txq of vif is added to active_txqs list for ATF TXQ scheduling
in the function ieee80211_queue_skb(), but it was not properly removed
before freeing the txq object. It was causing use after free of the txq
objects from the active_txqs list, result was kernel panic
due to invalid memory access.

Fix kernel invalid memory access by properly removing txq object
from active_txqs list before free the object.

Signed-off-by: Bhagavathi Perumal S <bperumal@codeaurora.org>
Acked-by: Toke Høiland-Jørgensen <toke@redhat.com>
Signed-off-by: Johannes Berg <johannes.berg@intel.com>
Acked-by: Takashi Iwai <tiwai@suse.de>

---
 net/mac80211/iface.c | 3 +++
 1 file changed, 3 insertions(+)

diff --git a/net/mac80211/iface.c b/net/mac80211/iface.c
index 4a6ff1482a9f..02d2e6f11e93 100644
--- a/net/mac80211/iface.c
+++ b/net/mac80211/iface.c
@@ -1908,6 +1908,9 @@ void ieee80211_if_remove(struct ieee80211_sub_if_data *sdata)
 	list_del_rcu(&sdata->list);
 	mutex_unlock(&sdata->local->iflist_mtx);
 
+	if (sdata->vif.txq)
+		ieee80211_txq_purge(sdata->local, to_txq_info(sdata->vif.txq));
+
 	synchronize_rcu();
 
 	if (sdata->dev) {
-- 
2.16.4