cfg80211: fix locking and lockdep complaints
To call cfg80211_get_chan_state() we need to lock
the wdev, so we need to lock the wdev_iter mutex
in cfg80211_can_use_iftype_chan(). This needs to
use nested locking for lockdep.
Also, cfg80211_get_chan_state() doesn't actually
use the rdev, so remove that completely including
the lock assertion that isn't needed.
Reported-by: Eliad Peller <eliad@wizery.com>
Signed-off-by: Johannes Berg <johannes.berg@intel.com>
diff --git a/net/wireless/util.c b/net/wireless/util.c
index f7a0647..26f8cd3 100644
--- a/net/wireless/util.c
+++ b/net/wireless/util.c
@@ -1059,7 +1059,16 @@
if (rdev->wiphy.software_iftypes & BIT(wdev_iter->iftype))
continue;
- cfg80211_get_chan_state(rdev, wdev_iter, &ch, &chmode);
+ /*
+ * We may be holding the "wdev" mutex, but now need to lock
+ * wdev_iter. This is OK because once we get here wdev_iter
+ * is not wdev (tested above), but we need to use the nested
+ * locking for lockdep.
+ */
+ mutex_lock_nested(&wdev_iter->mtx, 1);
+ __acquire(wdev_iter->mtx);
+ cfg80211_get_chan_state(wdev_iter, &ch, &chmode);
+ wdev_unlock(wdev_iter);
switch (chmode) {
case CHAN_MODE_UNDEFINED: