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>

1 files changed, 4 insertions, 11 deletions

diff --git a/net/mac80211/rate.c b/net/mac80211/rate.c
index a1e9fc7878aa..b051f125d3af 100644
--- a/net/mac80211/rate.c
+++ b/net/mac80211/rate.c
@@ -214,17 +214,16 @@ static ssize_t rcname_read(struct file *file, char __user *userbuf,
 				       ref->ops->name, len);
 }
 
-static const struct file_operations rcname_ops = {
+const struct file_operations rcname_ops = {
 	.read = rcname_read,
 	.open = simple_open,
 	.llseek = default_llseek,
 };
 #endif
 
-static struct rate_control_ref *rate_control_alloc(const char *name,
-					    struct ieee80211_local *local)
+static struct rate_control_ref *
+rate_control_alloc(const char *name, struct ieee80211_local *local)
 {
-	struct dentry *debugfsdir = NULL;
 	struct rate_control_ref *ref;
 
 	ref = kmalloc(sizeof(struct rate_control_ref), GFP_KERNEL);
@@ -234,13 +233,7 @@ static struct rate_control_ref *rate_control_alloc(const char *name,
 	if (!ref->ops)
 		goto free;
 
-#ifdef CONFIG_MAC80211_DEBUGFS
-	debugfsdir = debugfs_create_dir("rc", local->hw.wiphy->debugfsdir);
-	local->debugfs.rcdir = debugfsdir;
-	debugfs_create_file("name", 0400, debugfsdir, ref, &rcname_ops);
-#endif
-
-	ref->priv = ref->ops->alloc(&local->hw, debugfsdir);
+	ref->priv = ref->ops->alloc(&local->hw);
 	if (!ref->priv)
 		goto free;
 	return ref;