mac80211: fix associated vs. idle race

Eliad reports that if a scan finishes in the
middle of processing associated (however it
happens), the interface can go idle. This is
because we set assoc_data to NULL before we
set associated. Change the order so any idle
check will find either one of them.

Doing this requires duplicating the TX sync
processing, but I already have a patch to
delete that completely and will submit that
as soon as my driver changes to no longer
require it are submitted.

Reported-by: Eliad Peller <eliad@wizery.com>
Tested-by: Eliad Peller <eliad@wizery.com>
Signed-off-by: Johannes Berg <johannes.berg@intel.com>
Signed-off-by: John W. Linville <linville@tuxdriver.com>

diff --git a/net/mac80211/mlme.c b/net/mac80211/mlme.c
index 586d4fb..1495fb9 100644 (file)
--- a/net/mac80211/mlme.c
+++ b/net/mac80211/mlme.c
@@ -2238,14 +2238,28 @@ ieee80211_rx_mgmt_assoc_resp(struct ieee80211_sub_if_data *sdata,
        } else {
                printk(KERN_DEBUG "%s: associated\n", sdata->name);
 
-               ieee80211_destroy_assoc_data(sdata, true);
+               /* tell driver about sync done first */
+               if (assoc_data->synced) {
+                       drv_finish_tx_sync(sdata->local, sdata,
+                                          assoc_data->bss->bssid,
+                                          IEEE80211_TX_SYNC_ASSOC);
+                       assoc_data->synced = false;
+               }
 
                if (!ieee80211_assoc_success(sdata, *bss, mgmt, len)) {
                        /* oops -- internal error -- send timeout for now */
+                       ieee80211_destroy_assoc_data(sdata, true);
                        sta_info_destroy_addr(sdata, mgmt->bssid);
                        cfg80211_put_bss(*bss);
                        return RX_MGMT_CFG80211_ASSOC_TIMEOUT;
                }
+
+               /*
+                * destroy assoc_data afterwards, as otherwise an idle
+                * recalc after assoc_data is NULL but before associated
+                * is set can cause the interface to go idle
+                */
+               ieee80211_destroy_assoc_data(sdata, true);
        }
 
        return RX_MGMT_CFG80211_RX_ASSOC;