The channel switch notification should be sent under the
wdev/sdata-lock, preferably in the same moment as the channel change
happens, to avoid races by other callers (e.g. start/stop_ap).
This also adds the previously missing sdata_lock protection in
csa_finalize_work.
Reported-by: Johannes Berg <johannes@xxxxxxxxxxxxxxxx>
Signed-off-by: Simon Wunderlich <sw@xxxxxxxxxxxxxxxxxx>
---
drivers/net/wireless/ath/ath6kl/cfg80211.c | 2 ++
include/net/cfg80211.h | 3 ++-
net/mac80211/cfg.c | 21 +++++++++++++++------
net/wireless/nl80211.c | 9 +++------
4 files changed, 22 insertions(+), 13 deletions(-)
diff --git a/drivers/net/wireless/ath/ath6kl/cfg80211.c b/drivers/net/wireless/ath/ath6kl/cfg80211.c
index 36dc61d..43a05c9 100644
--- a/drivers/net/wireless/ath/ath6kl/cfg80211.c
+++ b/drivers/net/wireless/ath/ath6kl/cfg80211.c
@@ -1109,7 +1109,9 @@ void ath6kl_cfg80211_ch_switch_notify(struct ath6kl_vif *vif, int freq,
(mode == WMI_11G_HT20) ?
NL80211_CHAN_HT20 : NL80211_CHAN_NO_HT);
+ mutex_lock(vif->wdev->mtx);
cfg80211_ch_switch_notify(vif->ndev, &chandef);
+ mutex_unlock(vif->wdev->mtx);
}
static int ath6kl_cfg80211_add_key(struct wiphy *wiphy, struct net_device *ndev,
diff --git a/include/net/cfg80211.h b/include/net/cfg80211.h
index 633146b..874b5ae 100644
--- a/include/net/cfg80211.h
+++ b/include/net/cfg80211.h
@@ -4286,7 +4286,8 @@ bool cfg80211_reg_can_beacon(struct wiphy *wiphy,
* @dev: the device which switched channels
* @chandef: the new channel definition
*
- * Acquires wdev_lock, so must only be called from sleepable driver context!
+ * Caller must acquire wdev_lock, therefore must only be called from sleepable
+ * driver context!
*/
void cfg80211_ch_switch_notify(struct net_device *dev,
struct cfg80211_chan_def *chandef);
diff --git a/net/mac80211/cfg.c b/net/mac80211/cfg.c
index 1cdf2fb..a135e6f 100644
--- a/net/mac80211/cfg.c
+++ b/net/mac80211/cfg.c
@@ -2988,13 +2988,18 @@ void ieee80211_csa_finalize_work(struct work_struct *work)
struct ieee80211_local *local = sdata->local;
int err, changed = 0;
+ sdata_lock(sdata);
+ /* AP might have been stopped while waiting for the lock. */
+ if (!sdata->vif.csa_active)
+ goto unlock;
+
if (!ieee80211_sdata_running(sdata))
- return;
+ goto unlock;
sdata->radar_required = sdata->csa_radar_required;
err = ieee80211_vif_change_channel(sdata, &changed);
if (WARN_ON(err < 0))
- return;
+ goto unlock;
if (!local->use_chanctx) {
local->_oper_chandef = sdata->csa_chandef;
@@ -3003,11 +3008,13 @@ void ieee80211_csa_finalize_work(struct work_struct *work)
ieee80211_bss_info_change_notify(sdata, changed);
+ sdata->vif.csa_active = false;
switch (sdata->vif.type) {
case NL80211_IFTYPE_AP:
err = ieee80211_assign_beacon(sdata, sdata->u.ap.next_beacon);
if (err < 0)
- return;
+ goto unlock;
+
changed |= err;
kfree(sdata->u.ap.next_beacon);
sdata->u.ap.next_beacon = NULL;
@@ -3021,20 +3028,22 @@ void ieee80211_csa_finalize_work(struct work_struct *work)
case NL80211_IFTYPE_MESH_POINT:
err = ieee80211_mesh_finish_csa(sdata);
if (err < 0)
- return;
+ goto unlock;
break;
#endif
default:
WARN_ON(1);
- return;
+ goto unlock;
}
- sdata->vif.csa_active = false;
ieee80211_wake_queues_by_reason(&sdata->local->hw,
IEEE80211_MAX_QUEUE_MAP,
IEEE80211_QUEUE_STOP_REASON_CSA);
cfg80211_ch_switch_notify(sdata->dev, &sdata->csa_chandef);
+
+unlock:
+ sdata_unlock(sdata);
}
static int ieee80211_channel_switch(struct wiphy *wiphy, struct net_device *dev,
diff --git a/net/wireless/nl80211.c b/net/wireless/nl80211.c
index b1db645..c17c2c3 100644
--- a/net/wireless/nl80211.c
+++ b/net/wireless/nl80211.c
@@ -10820,21 +10820,18 @@ void cfg80211_ch_switch_notify(struct net_device *dev,
struct wiphy *wiphy = wdev->wiphy;
struct cfg80211_registered_device *rdev = wiphy_to_dev(wiphy);
+ ASSERT_WDEV_LOCK(wdev);
+
trace_cfg80211_ch_switch_notify(dev, chandef);
- wdev_lock(wdev);
-
if (WARN_ON(wdev->iftype != NL80211_IFTYPE_AP &&
wdev->iftype != NL80211_IFTYPE_P2P_GO &&
wdev->iftype != NL80211_IFTYPE_ADHOC &&
wdev->iftype != NL80211_IFTYPE_MESH_POINT))
- goto out;
+ return;
wdev->channel = chandef->chan;
nl80211_ch_switch_notify(rdev, dev, chandef, GFP_KERNEL);
-out:
- wdev_unlock(wdev);
- return;
}
EXPORT_SYMBOL(cfg80211_ch_switch_notify);
--
1.7.10.4
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