Patch "mwifiex: cfg80211: do not change virtual interface during scan processing" has been added to the 4.9-stable tree

This is a note to let you know that I've just added the patch titled

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

to the 4.9-stable tree which can be found at:
http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary

The filename of the patch is:
mwifiex-cfg80211-do-not-change-virtual-interface-during-scan-processing.patch
and it can be found in the queue-4.9 subdirectory.

If you, or anyone else, feels it should not be added to the stable tree, please let <[email protected]> know about it.

From: Limin Zhu <[email protected]>
Date: Thu, 30 Nov 2017 14:22:34 +0800
Subject: mwifiex: cfg80211: do not change virtual interface during scan processing

From: Limin Zhu <[email protected]>

[ Upstream commit c61cfe49f0f0f0d1f8b56d0b045838d597e8c3a3 ]

(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.

---
 drivers/net/wireless/marvell/mwifiex/cfg80211.c |    6 ++++++
 1 file changed, 6 insertions(+)

@@ -1109,6 +1109,12 @@ mwifiex_cfg80211_change_virtual_intf(str
 	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) {

Patches currently in stable-queue which might be from [email protected] are

queue-4.9/mwifiex-cfg80211-do-not-change-virtual-interface-during-scan-processing.patch