Date: Tue, 1 May 2007 17:25:13 +0200
From: Jiri Benc <jbenc@suse.cz>
To: Jan Kiszka <jan.kiszka@web.de>
Cc: Johannes Berg <johannes@sipsolutions.net>,
	Ivo Van Doorn <ivdoorn@gmail.com>,
	linux-wireless <linux-wireless@vger.kernel.org>,
	Michael Wu <flamingice@sourmilk.net>
Subject: Re: d80211: How does TX flow control work?
Message-ID: <20070501172513.2519f64b@logostar.upir.cz>
In-Reply-To: <46374C4C.50106@web.de>
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Sender: linux-wireless-owner@vger.kernel.org

On Tue, 01 May 2007 16:18:52 +0200, Jan Kiszka wrote:
> Already tried this lethal command? Works "fine" here...
> 
> #tc qdisc del dev wmaster0 root

I cannot reproduce it too.

Could you please (_without_ applying the attached patch):

- reproduce it with the latest wireless-dev (sorry, there were some changes
  in the networking core, we need to be sure this is not fixed already)
- send the dmesg output and/or any relevant logs?

If the problem still persists, could you please try again with the
following patch applied?

(Btw, you don't need to clone wireless-dev, just make another branch in
your local git tree and pull wireless-dev into it. That way you should
download a few hundred kilobytes only.)

Thanks,

 Jiri


Subject: [PATCH] mac80211: disallow transmitting when 802.11 qdisc is removed

Signed-off-by: Jiri Benc <jbenc@suse.cz>

---
 net/mac80211/ieee80211.c |    9 +++++++++
 1 files changed, 9 insertions(+)

--- mac80211.orig/net/mac80211/ieee80211.c
+++ mac80211/net/mac80211/ieee80211.c
@@ -1435,6 +1435,15 @@ static int ieee80211_master_start_xmit(s
 	int headroom;
 	int ret;
 
+	if (unlikely(!ieee80211_qdisc_installed(dev))) {
+		netif_stop_queue(dev);
+		if (net_ratelimit())
+			printk(KERN_ERR "%s: ieee80211 qdisc not installed\n",
+			       dev->name);
+		dev_kfree_skb(skb);
+		return 0;
+	}
+
 	/*
 	 * copy control out of the skb so other people can use skb->cb
 	 */


-- 
Jiri Benc
SUSE Labs