OpenWrt – Rev 4
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From: =?UTF-8?q?Rafa=C5=82=20Mi=C5=82ecki?= <zajec5@gmail.com>
Date: Thu, 9 Jul 2015 00:07:59 +0200
Subject: [PATCH] brcmfmac: workaround bug with some inconsistent BSSes state
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Signed-off-by: Rafał Miłecki <zajec5@gmail.com>
---
--- a/drivers/net/wireless/broadcom/brcm80211/brcmfmac/cfg80211.c
+++ b/drivers/net/wireless/broadcom/brcm80211/brcmfmac/cfg80211.c
@@ -614,9 +614,37 @@ static struct wireless_dev *brcmf_cfg802
enum nl80211_iftype type,
struct vif_params *params)
{
+ struct net_device *dev;
struct wireless_dev *wdev;
int err;
+ /*
+ * There is a bug with in-firmware BSS management. When adding virtual
+ * interface brcmfmac first tells firmware to create new BSS and then
+ * it creates new struct net_device.
+ *
+ * If creating/registering netdev(ice) fails, BSS remains in some bugged
+ * state. It conflicts with existing BSSes by overtaking their auth
+ * requests.
+ *
+ * It results in one BSS (addresss X) sending beacons and another BSS
+ * (address Y) replying to authentication requests. This makes interface
+ * unusable as AP.
+ *
+ * To workaround this bug we may try to guess if register_netdev(ice)
+ * will fail. The most obvious case is using interface name that already
+ * exists. This is actually quite likely with brcmfmac & some user space
+ * scripts as brcmfmac doesn't allow deleting virtual interfaces.
+ * So this bug can be triggered even by something trivial like:
+ * iw dev wlan0 delete
+ * iw phy phy0 interface add wlan0 type __ap
+ */
+ dev = dev_get_by_name(&init_net, name);
+ if (dev) {
+ dev_put(dev);
+ return ERR_PTR(-ENFILE);
+ }
+
brcmf_dbg(TRACE, "enter: %s type %d\n", name, type);
err = brcmf_vif_add_validate(wiphy_to_cfg(wiphy), type);
if (err) {