mac80211: fix mesh deadlock

The patch "cfg80211/mac80211: use cfg80211 wdev mutex in
mac80211" introduced several deadlocks by converting the
ifmsh->mtx to wdev->mtx. Solve these by:

1. drop the cancel_work_sync() in ieee80211_stop_mesh().
   Instead make the mesh work conditional on whether the mesh
   is running or not.
2. lock the mesh work with sdata_lock() to protect beacon
   updates and prevent races with wdev->mesh_id_len or
   cfg80211.

Signed-off-by: Thomas Pedersen <thomas@cozybit.com>
Signed-off-by: Johannes Berg <johannes.berg@intel.com>

1 files changed, 1 insertions, 6 deletions

diff --git a/net/mac80211/mesh_plink.c b/net/mac80211/mesh_plink.c
index 6c4da99bc4fb..09bebed99416 100644
--- a/net/mac80211/mesh_plink.c
+++ b/net/mac80211/mesh_plink.c
@@ -517,9 +517,7 @@ void mesh_neighbour_update(struct ieee80211_sub_if_data *sdata,
         ieee80211_mps_frame_release(sta, elems);
 out:
         rcu_read_unlock();
-        sdata_lock(sdata);
         ieee80211_mbss_info_change_notify(sdata, changed);
-        sdata_unlock(sdata);
 }
 
 static void mesh_plink_timer(unsigned long data)
@@ -1070,9 +1068,6 @@ void mesh_rx_plink_frame(struct ieee80211_sub_if_data *sdata,
 
         rcu_read_unlock();
 
-        if (changed) {
-                sdata_lock(sdata);
+        if (changed)
                 ieee80211_mbss_info_change_notify(sdata, changed);
-                sdata_unlock(sdata);
-        }
 }