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authorFelix Fietkau <nbd@openwrt.org>2011-01-24 19:28:49 +0100
committerJohn W. Linville <linville@tuxdriver.com>2011-01-25 16:28:56 -0500
commiteb3e554b4b3a56386ef5214dbe0e3935a350178b (patch)
tree7c107dadb64f044c7747c41e369f9780ab611cb1
parentbdc4bf652bc0271ba8f1f25bbd3dbac90bead44e (diff)
downloadlinux-eb3e554b4b3a56386ef5214dbe0e3935a350178b.tar.gz
mac80211: fix a crash in ieee80211_beacon_get_tim on change_interface
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>
-rw-r--r--net/mac80211/tx.c3
1 files changed, 3 insertions, 0 deletions
diff --git a/net/mac80211/tx.c b/net/mac80211/tx.c
index 5950e3abead9..b64b42bc774b 100644
--- a/net/mac80211/tx.c
+++ b/net/mac80211/tx.c
@@ -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)