From: Johannes Berg <johannes.berg@xxxxxxxxx>
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@xxxxxxxxxx>
Signed-off-by: Johannes Berg <johannes.berg@xxxxxxxxx>
---
net/wireless/chan.c | 4 +---
net/wireless/core.h | 3 +--
net/wireless/util.c | 11 ++++++++++-
3 files changed, 12 insertions(+), 6 deletions(-)
diff --git a/net/wireless/chan.c b/net/wireless/chan.c
index 434c56b..1cc4b7c 100644
--- a/net/wireless/chan.c
+++ b/net/wireless/chan.c
@@ -103,15 +103,13 @@ int cfg80211_set_monitor_channel(struct cfg80211_registered_device *rdev,
}
void
-cfg80211_get_chan_state(struct cfg80211_registered_device *rdev,
- struct wireless_dev *wdev,
+cfg80211_get_chan_state(struct wireless_dev *wdev,
struct ieee80211_channel **chan,
enum cfg80211_chan_mode *chanmode)
{
*chan = NULL;
*chanmode = CHAN_MODE_UNDEFINED;
- ASSERT_RDEV_LOCK(rdev);
ASSERT_WDEV_LOCK(wdev);
if (!netif_running(wdev->netdev))
diff --git a/net/wireless/core.h b/net/wireless/core.h
index eae5a25..bac97da 100644
--- a/net/wireless/core.h
+++ b/net/wireless/core.h
@@ -463,8 +463,7 @@ cfg80211_can_use_chan(struct cfg80211_registered_device *rdev,
}
void
-cfg80211_get_chan_state(struct cfg80211_registered_device *rdev,
- struct wireless_dev *wdev,
+cfg80211_get_chan_state(struct wireless_dev *wdev,
struct ieee80211_channel **chan,
enum cfg80211_chan_mode *chanmode);
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 @@ int cfg80211_can_use_iftype_chan(struct cfg80211_registered_device *rdev,
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:
--
1.7.10.4
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