[ 21/42] mac80211: clean up remain-on-channel on interface stop

From: Greg KH
Date: Thu Jun 14 2012 - 20:03:48 EST


3.4-stable review patch. If anyone has any objections, please let me know.

------------------

From: Johannes Berg <johannes.berg@xxxxxxxxx>

commit 71ecfa1893034eeb1c93e02e22ee2ad26d080858 upstream.

When any interface goes down, it could be the one that we
were doing a remain-on-channel with. We therefore need to
cancel the remain-on-channel and flush the related work
structs so they don't run after the interface has been
removed or even destroyed.

It's also possible in this case that an off-channel SKB
was never transmitted, so free it if this is the case.
Note that this can also happen if the driver finishes
the off-channel period without ever starting it.

Reported-by: Nirav Shah <nirav.j2.shah@xxxxxxxxx>
Signed-off-by: Johannes Berg <johannes.berg@xxxxxxxxx>
Signed-off-by: John W. Linville <linville@xxxxxxxxxxxxx>
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>

---
net/mac80211/iface.c | 12 ++++++++++++
net/mac80211/offchannel.c | 16 ++++++++++++++++
2 files changed, 28 insertions(+)

--- a/net/mac80211/iface.c
+++ b/net/mac80211/iface.c
@@ -514,6 +514,18 @@ static void ieee80211_do_stop(struct iee
ieee80211_configure_filter(local);
break;
default:
+ mutex_lock(&local->mtx);
+ if (local->hw_roc_dev == sdata->dev &&
+ local->hw_roc_channel) {
+ /* ignore return value since this is racy */
+ drv_cancel_remain_on_channel(local);
+ ieee80211_queue_work(&local->hw, &local->hw_roc_done);
+ }
+ mutex_unlock(&local->mtx);
+
+ flush_work(&local->hw_roc_start);
+ flush_work(&local->hw_roc_done);
+
flush_work(&sdata->work);
/*
* When we get here, the interface is marked down.
--- a/net/mac80211/offchannel.c
+++ b/net/mac80211/offchannel.c
@@ -234,6 +234,22 @@ static void ieee80211_hw_roc_done(struct
return;
}

+ /* was never transmitted */
+ if (local->hw_roc_skb) {
+ u64 cookie;
+
+ cookie = local->hw_roc_cookie ^ 2;
+
+ cfg80211_mgmt_tx_status(local->hw_roc_dev, cookie,
+ local->hw_roc_skb->data,
+ local->hw_roc_skb->len, false,
+ GFP_KERNEL);
+
+ kfree_skb(local->hw_roc_skb);
+ local->hw_roc_skb = NULL;
+ local->hw_roc_skb_for_status = NULL;
+ }
+
if (!local->hw_roc_for_tx)
cfg80211_remain_on_channel_expired(local->hw_roc_dev,
local->hw_roc_cookie,


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