From 6cb5f3ea4654faf8c28b901266e960b1a4787b26 Mon Sep 17 00:00:00 2001
From: Johannes Berg <johannes.berg@intel.com>
Date: Thu, 23 Apr 2020 11:13:49 +0200
Subject: mac80211: populate debugfs only after cfg80211 init

When fixing the initialization race, we neglected to account for
the fact that debugfs is initialized in wiphy_register(), and
some debugfs things went missing (or rather were rerooted to the
global debugfs root).

Fix this by adding debugfs entries only after wiphy_register().
This requires some changes in the rate control code since it
currently adds debugfs at alloc time, which can no longer be
done after the reordering.

Reported-by: Jouni Malinen <j@w1.fi>
Reported-by: kernel test robot <rong.a.chen@intel.com>
Reported-by: Hauke Mehrtens <hauke@hauke-m.de>
Reported-by: Felix Fietkau <nbd@nbd.name>
Cc: stable@vger.kernel.org
Fixes: 52e04b4ce5d0 ("mac80211: fix race in ieee80211_register_hw()")
Signed-off-by: Johannes Berg <johannes.berg@intel.com>
Acked-by: Sumit Garg <sumit.garg@linaro.org>
Link: https://lore.kernel.org/r/20200423111344.0e00d3346f12.Iadc76a03a55093d94391fc672e996a458702875d@changeid
Signed-off-by: Johannes Berg <johannes.berg@intel.com>
---
 net/mac80211/rc80211_minstrel_ht.c | 19 +++++++++++++------
 1 file changed, 13 insertions(+), 6 deletions(-)

(limited to 'net/mac80211/rc80211_minstrel_ht.c')

diff --git a/net/mac80211/rc80211_minstrel_ht.c b/net/mac80211/rc80211_minstrel_ht.c
index 694a31978a04..5dc3e5bc4e64 100644
--- a/net/mac80211/rc80211_minstrel_ht.c
+++ b/net/mac80211/rc80211_minstrel_ht.c
@@ -1635,7 +1635,7 @@ minstrel_ht_init_cck_rates(struct minstrel_priv *mp)
 }
 
 static void *
-minstrel_ht_alloc(struct ieee80211_hw *hw, struct dentry *debugfsdir)
+minstrel_ht_alloc(struct ieee80211_hw *hw)
 {
 	struct minstrel_priv *mp;
 
@@ -1673,7 +1673,17 @@ minstrel_ht_alloc(struct ieee80211_hw *hw, struct dentry *debugfsdir)
 	mp->update_interval = HZ / 10;
 	mp->new_avg = true;
 
+	minstrel_ht_init_cck_rates(mp);
+
+	return mp;
+}
+
 #ifdef CONFIG_MAC80211_DEBUGFS
+static void minstrel_ht_add_debugfs(struct ieee80211_hw *hw, void *priv,
+				    struct dentry *debugfsdir)
+{
+	struct minstrel_priv *mp = priv;
+
 	mp->fixed_rate_idx = (u32) -1;
 	debugfs_create_u32("fixed_rate_idx", S_IRUGO | S_IWUGO, debugfsdir,
 			   &mp->fixed_rate_idx);
@@ -1681,12 +1691,8 @@ minstrel_ht_alloc(struct ieee80211_hw *hw, struct dentry *debugfsdir)
 			   &mp->sample_switch);
 	debugfs_create_bool("new_avg", S_IRUGO | S_IWUSR, debugfsdir,
 			   &mp->new_avg);
-#endif
-
-	minstrel_ht_init_cck_rates(mp);
-
-	return mp;
 }
+#endif
 
 static void
 minstrel_ht_free(void *priv)
@@ -1725,6 +1731,7 @@ static const struct rate_control_ops mac80211_minstrel_ht = {
 	.alloc = minstrel_ht_alloc,
 	.free = minstrel_ht_free,
 #ifdef CONFIG_MAC80211_DEBUGFS
+	.add_debugfs = minstrel_ht_add_debugfs,
 	.add_sta_debugfs = minstrel_ht_add_sta_debugfs,
 #endif
 	.get_expected_throughput = minstrel_ht_get_expected_throughput,
-- 
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