# \[PATCH 4.9 195/207\] cfg80211: call cfg80211\_stop\_ap when switch from P2P\_GO type

- From: Greg Kroah-Hartman \<gregkh@linuxfoundation.org\>
- Date: 2021-11-24 12:29:42 
- List: stable
- Page: https://ratatoskr.run/stable/2021/11/1584124
- Thread: https://ratatoskr.run/stable/2021/11/1583929/t/3.md

```text
From: Nguyen Dinh Phi <redacted>

commit 563fbefed46ae4c1f70cffb8eb54c02df480b2c2 upstream.

If the userspace tools switch from NL80211_IFTYPE_P2P_GO to
NL80211_IFTYPE_ADHOC via send_msg(NL80211_CMD_SET_INTERFACE), it
does not call the cleanup cfg80211_stop_ap(), this leads to the
initialization of in-use data. For example, this path re-init the
sdata->assigned_chanctx_list while it is still an element of
assigned_vifs list, and makes that linked list corrupt.

Signed-off-by: Nguyen Dinh Phi <redacted>
Reported-by: <redacted>
Link: https://lore.kernel.org/r/20211027173722.777287-1-phind.uet@gmail.com
Cc: <redacted>
Fixes: ac800140c20e ("cfg80211: .stop_ap when interface is going down")
Signed-off-by: Johannes Berg <redacted>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
---
 net/wireless/util.c |    1 +
 1 file changed, 1 insertion(+)

--- a/net/wireless/util.c
+++ b/net/wireless/util.c
@@ -1035,6 +1035,7 @@ int cfg80211_change_iface(struct cfg8021
 
 		switch (otype) {
 		case NL80211_IFTYPE_AP:
+		case NL80211_IFTYPE_P2P_GO:
 			cfg80211_stop_ap(rdev, dev, true);
 			break;
 		case NL80211_IFTYPE_ADHOC:


```