mac80211: fix a crash in ieee80211_beacon_get_tim on change_interface
authorFelix Fietkau <nbd@openwrt.org>
Mon, 24 Jan 2011 18:28:49 +0000 (19:28 +0100)
committerJohn W. Linville <linville@tuxdriver.com>
Tue, 25 Jan 2011 21:28:56 +0000 (16:28 -0500)
Some drivers (e.g. ath9k) do not always disable beacons when they're
supposed to. When an interface is changed using the change_interface op,
the mode specific sdata part is in an undefined state and trying to
get a beacon at this point can produce weird crashes.

To fix this, add a check for ieee80211_sdata_running before using
anything from the sdata.

Signed-off-by: Felix Fietkau <nbd@openwrt.org>
Cc: stable@kernel.org
Signed-off-by: John W. Linville <linville@tuxdriver.com>
net/mac80211/tx.c

index 5950e3abead9b49a7bfc4a8d17d77ce250d1b578..b64b42bc774be82ce40133237624a848d237289f 100644 (file)
@@ -2230,6 +2230,9 @@ struct sk_buff *ieee80211_beacon_get_tim(struct ieee80211_hw *hw,
 
        sdata = vif_to_sdata(vif);
 
+       if (!ieee80211_sdata_running(sdata))
+               goto out;
+
        if (tim_offset)
                *tim_offset = 0;
        if (tim_length)