mwifiex: cfg80211: do not change virtual interface during scan processing

(1) Change virtual interface operation in cfg80211 process reset and
reinitilize private data structure.
(2) Scan result event processed in main process will dereference private
data structure concurrently, ocassionly crash the kernel.

The cornel case could be trigger by below steps:
(1) wpa_cli mlan0 scan
(2) ./hostapd mlan0.conf

Cfg80211 asynchronous scan procedure is not all the time operated
under rtnl lock, here we add the protect to serialize the cfg80211
scan and change_virtual interface operation.

Signed-off-by: Limin Zhu <liminzhu@marvell.com>
Signed-off-by: Xinming Hu <huxm@marvell.com>
Signed-off-by: Kalle Valo <kvalo@codeaurora.org>

diff --git a/drivers/net/wireless/marvell/mwifiex/cfg80211.c b/drivers/net/wireless/marvell/mwifiex/cfg80211.c
index 4d45df8128dbf79866dc95e64a03d0d93b35e53c..ce4432c535f0543757345d352f32a5b08972c4ba 100644 (file)
--- a/drivers/net/wireless/marvell/mwifiex/cfg80211.c
+++ b/drivers/net/wireless/marvell/mwifiex/cfg80211.c
@@ -1116,6 +1116,12 @@ mwifiex_cfg80211_change_virtual_intf(struct wiphy *wiphy,
        struct mwifiex_private *priv = mwifiex_netdev_get_priv(dev);
        enum nl80211_iftype curr_iftype = dev->ieee80211_ptr->iftype;
 
+       if (priv->scan_request) {
+               mwifiex_dbg(priv->adapter, ERROR,
+                           "change virtual interface: scan in process\n");
+               return -EBUSY;
+       }
+
        switch (curr_iftype) {
        case NL80211_IFTYPE_ADHOC:
                switch (type) {