[PATCH 5.4 126/168] mac80211: populate debugfs only after cfg80211 init

From: Greg Kroah-Hartman
Date: Tue Apr 28 2020 - 14:43:06 EST


From: Johannes Berg <johannes.berg@xxxxxxxxx>

commit 6cb5f3ea4654faf8c28b901266e960b1a4787b26 upstream.

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@xxxxx>
Reported-by: kernel test robot <rong.a.chen@xxxxxxxxx>
Reported-by: Hauke Mehrtens <hauke@xxxxxxxxxx>
Reported-by: Felix Fietkau <nbd@xxxxxxxx>
Cc: stable@xxxxxxxxxxxxxxx
Fixes: 52e04b4ce5d0 ("mac80211: fix race in ieee80211_register_hw()")
Signed-off-by: Johannes Berg <johannes.berg@xxxxxxxxx>
Acked-by: Sumit Garg <sumit.garg@xxxxxxxxxx>
Link: https://lore.kernel.org/r/20200423111344.0e00d3346f12.Iadc76a03a55093d94391fc672e996a458702875d@changeid
Signed-off-by: Johannes Berg <johannes.berg@xxxxxxxxx>
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>

---
drivers/net/wireless/intel/iwlegacy/3945-rs.c | 2 +-
drivers/net/wireless/intel/iwlegacy/4965-rs.c | 2 +-
drivers/net/wireless/intel/iwlwifi/dvm/rs.c | 2 +-
drivers/net/wireless/intel/iwlwifi/mvm/rs.c | 2 +-
drivers/net/wireless/realtek/rtlwifi/rc.c | 2 +-
include/net/mac80211.h | 4 +++-
net/mac80211/main.c | 5 +++--
net/mac80211/rate.c | 15 ++++-----------
net/mac80211/rate.h | 23 +++++++++++++++++++++++
net/mac80211/rc80211_minstrel_ht.c | 19 +++++++++++++------
10 files changed, 51 insertions(+), 25 deletions(-)

--- a/drivers/net/wireless/intel/iwlegacy/3945-rs.c
+++ b/drivers/net/wireless/intel/iwlegacy/3945-rs.c
@@ -374,7 +374,7 @@ out:
}

static void *
-il3945_rs_alloc(struct ieee80211_hw *hw, struct dentry *debugfsdir)
+il3945_rs_alloc(struct ieee80211_hw *hw)
{
return hw->priv;
}
--- a/drivers/net/wireless/intel/iwlegacy/4965-rs.c
+++ b/drivers/net/wireless/intel/iwlegacy/4965-rs.c
@@ -2474,7 +2474,7 @@ il4965_rs_fill_link_cmd(struct il_priv *
}

static void *
-il4965_rs_alloc(struct ieee80211_hw *hw, struct dentry *debugfsdir)
+il4965_rs_alloc(struct ieee80211_hw *hw)
{
return hw->priv;
}
--- a/drivers/net/wireless/intel/iwlwifi/dvm/rs.c
+++ b/drivers/net/wireless/intel/iwlwifi/dvm/rs.c
@@ -3019,7 +3019,7 @@ static void rs_fill_link_cmd(struct iwl_
cpu_to_le16(priv->lib->bt_params->agg_time_limit);
}

-static void *rs_alloc(struct ieee80211_hw *hw, struct dentry *debugfsdir)
+static void *rs_alloc(struct ieee80211_hw *hw)
{
return hw->priv;
}
--- a/drivers/net/wireless/intel/iwlwifi/mvm/rs.c
+++ b/drivers/net/wireless/intel/iwlwifi/mvm/rs.c
@@ -3663,7 +3663,7 @@ static void rs_fill_lq_cmd(struct iwl_mv
cpu_to_le16(iwl_mvm_coex_agg_time_limit(mvm, sta));
}

-static void *rs_alloc(struct ieee80211_hw *hw, struct dentry *debugfsdir)
+static void *rs_alloc(struct ieee80211_hw *hw)
{
return hw->priv;
}
--- a/drivers/net/wireless/realtek/rtlwifi/rc.c
+++ b/drivers/net/wireless/realtek/rtlwifi/rc.c
@@ -261,7 +261,7 @@ static void rtl_rate_update(void *ppriv,
{
}

-static void *rtl_rate_alloc(struct ieee80211_hw *hw, struct dentry *debugfsdir)
+static void *rtl_rate_alloc(struct ieee80211_hw *hw)
{
struct rtl_priv *rtlpriv = rtl_priv(hw);
return rtlpriv;
--- a/include/net/mac80211.h
+++ b/include/net/mac80211.h
@@ -5933,7 +5933,9 @@ enum rate_control_capabilities {
struct rate_control_ops {
unsigned long capa;
const char *name;
- void *(*alloc)(struct ieee80211_hw *hw, struct dentry *debugfsdir);
+ void *(*alloc)(struct ieee80211_hw *hw);
+ void (*add_debugfs)(struct ieee80211_hw *hw, void *priv,
+ struct dentry *debugfsdir);
void (*free)(void *priv);

void *(*alloc_sta)(void *priv, struct ieee80211_sta *sta, gfp_t gfp);
--- a/net/mac80211/main.c
+++ b/net/mac80211/main.c
@@ -1155,8 +1155,6 @@ int ieee80211_register_hw(struct ieee802
local->tx_headroom = max_t(unsigned int , local->hw.extra_tx_headroom,
IEEE80211_TX_STATUS_HEADROOM);

- debugfs_hw_add(local);
-
/*
* if the driver doesn't specify a max listen interval we
* use 5 which should be a safe default
@@ -1248,6 +1246,9 @@ int ieee80211_register_hw(struct ieee802
if (result < 0)
goto fail_wiphy_register;

+ debugfs_hw_add(local);
+ rate_control_add_debugfs(local);
+
rtnl_lock();

/* add one default STA interface if supported */
--- a/net/mac80211/rate.c
+++ b/net/mac80211/rate.c
@@ -214,17 +214,16 @@ static ssize_t rcname_read(struct file *
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_con
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;
--- a/net/mac80211/rate.h
+++ b/net/mac80211/rate.h
@@ -60,6 +60,29 @@ static inline void rate_control_add_sta_
#endif
}

+extern const struct file_operations rcname_ops;
+
+static inline void rate_control_add_debugfs(struct ieee80211_local *local)
+{
+#ifdef CONFIG_MAC80211_DEBUGFS
+ struct dentry *debugfsdir;
+
+ if (!local->rate_ctrl)
+ return;
+
+ if (!local->rate_ctrl->ops->add_debugfs)
+ return;
+
+ debugfsdir = debugfs_create_dir("rc", local->hw.wiphy->debugfsdir);
+ local->debugfs.rcdir = debugfsdir;
+ debugfs_create_file("name", 0400, debugfsdir,
+ local->rate_ctrl, &rcname_ops);
+
+ local->rate_ctrl->ops->add_debugfs(&local->hw, local->rate_ctrl->priv,
+ debugfsdir);
+#endif
+}
+
void ieee80211_check_rate_mask(struct ieee80211_sub_if_data *sdata);

/* Get a reference to the rate control algorithm. If `name' is NULL, get the
--- a/net/mac80211/rc80211_minstrel_ht.c
+++ b/net/mac80211/rc80211_minstrel_ht.c
@@ -1631,7 +1631,7 @@ minstrel_ht_init_cck_rates(struct minstr
}

static void *
-minstrel_ht_alloc(struct ieee80211_hw *hw, struct dentry *debugfsdir)
+minstrel_ht_alloc(struct ieee80211_hw *hw)
{
struct minstrel_priv *mp;

@@ -1668,18 +1668,24 @@ minstrel_ht_alloc(struct ieee80211_hw *h
mp->hw = hw;
mp->update_interval = 100;

+ 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);
debugfs_create_u32("sample_switch", S_IRUGO | S_IWUSR, debugfsdir,
&mp->sample_switch);
-#endif
-
- minstrel_ht_init_cck_rates(mp);
-
- return mp;
}
+#endif

static void
minstrel_ht_free(void *priv)
@@ -1718,6 +1724,7 @@ static const struct rate_control_ops mac
.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,