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regression with kernel 3.8

PATCH In review Fabio Rossi 3 participants 6 messages Feb 25, 2013 – Feb 26, 2013 mac80211

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Fabio Rossi

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#0 lore raw

I'm using the latest wireless-testing.git and I have found a regression with kernel 3.8. I don't know if this is related to the driver I'm using (ath5k) but I have bisected the problem to the commit 6c17b77b67587b9f9e3070fb89fe98cef3187131 (mac80211: Fix tx queue handling during scans). Basically the authentication and association infos don't appear anymore in the kernel logs during a connection to my access point.

Tell me what you need to further debug the issue and solve the problem.

Fabio

#1 lore raw
Quoted 8 lines · Fabio Rossi

I'm using the latest wireless-testing.git and I have found a regression with kernel 3.8. I don't know if this is related to the driver I'm using (ath5k) but I have bisected the problem to the commit 6c17b77b67587b9f9e3070fb89fe98cef3187131 (mac80211: Fix tx queue handling during scans). Basically the authentication and association infos don't appear anymore in the kernel logs during a connection to my access point.

Tell me what you need to further debug the issue and solve the problem.

That patch is after 3.8.

Johannes, this looks like a problem with the changes you made when applying that patch. I really should have tested the result before now.

I think the off-channel frames are getting queued rather than passed down to the driver, which obviously isn't what we want. I'll get this fixed.

Seth

#2 lore raw

PATCH 1/1 mac80211: Ensure off-channel frames don't get queued

Commit 6c17b77b67587b9f9e3070fb89fe98cef3187131 (mac80211: Fix tx queue handling during scans) contains a bug that causes off-channel frames to get queued when they should be handed down to the driver for transmit. Prevent this from happening.

Reported-by Fabio Rossi <[email protected]>
Signed-off-by Seth Forshee <[email protected]>

---

Fabio, this patch should fix the problem. Can you verify?

Johannes, this prevents the off-channel frames from getting queued without affecting the fast path. It does however make the indentation awfully deep ...

 net/mac80211/tx.c |   56 +++++++++++++++++++++++++++++------------------------
 1 file changed, 31 insertions(+), 25 deletions(-)
net/mac80211/tx.c +31 -25
index 5b9602b..b1296e7 100644
@@ -1231,34 +1231,40 @@ static bool ieee80211_tx_frags(struct ieee80211_local *local,
 		if (local->queue_stop_reasons[q] ||
 		    (!txpending && !skb_queue_empty(&local->pending[q]))) {
 			if (unlikely(info->flags &
-					IEEE80211_TX_INTFL_OFFCHAN_TX_OK &&
-				     local->queue_stop_reasons[q] &
-					~BIT(IEEE80211_QUEUE_STOP_REASON_OFFCHANNEL))) {
+				     IEEE80211_TX_INTFL_OFFCHAN_TX_OK)) {
+				if (local->queue_stop_reasons[q] &
+				    ~BIT(IEEE80211_QUEUE_STOP_REASON_OFFCHANNEL)) {
+					/*
+					 * Drop off-channel frames if queues
+					 * are stopped for any reason other
+					 * than off-channel operation. Never
+					 * queue them.
+					 */
+					spin_unlock_irqrestore(
+						&local->queue_stop_reason_lock,
+						flags);
+					ieee80211_purge_tx_queue(&local->hw,
+								 skbs);
+					return true;
+				}
+			} else {
+
 				/*
-				 * Drop off-channel frames if queues are stopped
-				 * for any reason other than off-channel
-				 * operation. Never queue them.
+				 * Since queue is stopped, queue up frames for
+				 * later transmission from the tx-pending
+				 * tasklet when the queue is woken again.
 				 */
-				spin_unlock_irqrestore(
-					&local->queue_stop_reason_lock, flags);
-				ieee80211_purge_tx_queue(&local->hw, skbs);
-				return true;
+				if (txpending)
+					skb_queue_splice_init(skbs,
+							      &local->pending[q]);
+				else
+					skb_queue_splice_tail_init(skbs,
+								   &local->pending[q]);
+
+				spin_unlock_irqrestore(&local->queue_stop_reason_lock,
+						       flags);
+				return false;
 			}
-
-			/*
-			 * Since queue is stopped, queue up frames for later
-			 * transmission from the tx-pending tasklet when the
-			 * queue is woken again.
-			 */
-			if (txpending)
-				skb_queue_splice_init(skbs, &local->pending[q]);
-			else
-				skb_queue_splice_tail_init(skbs,
-							   &local->pending[q]);
-
-			spin_unlock_irqrestore(&local->queue_stop_reason_lock,
-					       flags);
-			return false;
 		}
 		spin_unlock_irqrestore(&local->queue_stop_reason_lock, flags);
Signature · 1 line
1.7.9.5
maintainer
#3 lore raw

Re: [PATCH] mac80211: Ensure off-channel frames don't get queued

Quoted 7 lines · Seth Forshee

Commit 6c17b77b67587b9f9e3070fb89fe98cef3187131 (mac80211: Fix tx queue handling during scans) contains a bug that causes off-channel frames to get queued when they should be handed down to the driver for transmit. Prevent this from happening.

Reported-by Fabio Rossi <[email protected]>
Signed-off-by Seth Forshee <[email protected]>
Quoted 7 lines

---

Fabio, this patch should fix the problem. Can you verify?

Johannes, this prevents the off-channel frames from getting queued without affecting the fast path. It does however make the indentation awfully deep ...

Ugh .. I do see the bug, but the indentation is crap. I'll apply this anyway, and then we can sort it out later.

johannes

maintainer
#4 lore raw
In reply to Seth Forshee
Quoted 8 lines · Seth Forshee
Quoted 7 lines · Fabio Rossi

I'm using the latest wireless-testing.git and I have found a regression with kernel 3.8. I don't know if this is related to the driver I'm using (ath5k) but I have bisected the problem to the commit 6c17b77b67587b9f9e3070fb89fe98cef3187131 (mac80211: Fix tx queue handling during scans). Basically the authentication and association infos don't appear anymore in the kernel logs during a connection to my access point.

Quoted 6 lines
Quoted 1 line

Tell me what you need to further debug the issue and solve the problem.

That patch is after 3.8.

Johannes, this looks like a problem with the changes you made when applying that patch. I really should have tested the result before now.

Hmm, crap. Sorry about that!

Quoted 3 lines

I think the off-channel frames are getting queued rather than passed down to the driver, which obviously isn't what we want. I'll get this fixed.

I saw you posted it, I'll take a closer look tomorrow morning.

johannes

#5 lore raw
Quoted 16 lines · Johannes Berg
Quoted 8 lines · Seth Forshee
Quoted 7 lines · Fabio Rossi

I'm using the latest wireless-testing.git and I have found a regression with kernel 3.8. I don't know if this is related to the driver I'm using (ath5k) but I have bisected the problem to the commit 6c17b77b67587b9f9e3070fb89fe98cef3187131 (mac80211: Fix tx queue handling during scans). Basically the authentication and association infos don't appear anymore in the kernel logs during a connection to my access point.

Quoted 6 lines
Quoted 1 line

Tell me what you need to further debug the issue and solve the problem.

That patch is after 3.8.

Johannes, this looks like a problem with the changes you made when applying that patch. I really should have tested the result before now.

Quoted 7 lines

Hmm, crap. Sorry about that!

Quoted 3 lines

I think the off-channel frames are getting queued rather than passed down to the driver, which obviously isn't what we want. I'll get this fixed.

I saw you posted it, I'll take a closer look tomorrow morning.

Have you had a chance to look at the patch yet? I think we ought to try and get this fixed pretty quickly.

Seth