Linux IEEE 802.15.4 and 6LoWPAN development
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From: Alexander Aring <alex.aring@gmail.com>
To: linux-wpan@vger.kernel.org
Cc: kernel@pengutronix.de, Alexander Aring <alex.aring@gmail.com>,
	Michael Hennerich <michael.hennerich@analog.com>
Subject: [PATCH bluetooth] mac802154: tx: fix synced xmit deadlock
Date: Wed,  9 Dec 2015 23:15:31 +0100	[thread overview]
Message-ID: <1449699331-17563-1-git-send-email-alex.aring@gmail.com> (raw)

This patch reverts 6001d52 ("mac802154: tx: don't allow if down while
sync tx"). This has side effects with stop callback which flush the
transmit workqueue. The stop callback will wait until the workqueue is
flushed and holding the rtnl lock. That means it can happen that the stop
callback waits forever because it try to lock the rtnl mutex which is
already hold by stop callback.

Cc: Michael Hennerich <michael.hennerich@analog.com>
Signed-off-by: Alexander Aring <alex.aring@gmail.com>
---
 net/mac802154/tx.c | 9 ---------
 1 file changed, 9 deletions(-)

diff --git a/net/mac802154/tx.c b/net/mac802154/tx.c
index 3827f35..7e25345 100644
--- a/net/mac802154/tx.c
+++ b/net/mac802154/tx.c
@@ -38,12 +38,6 @@ void ieee802154_xmit_worker(struct work_struct *work)
 	struct net_device *dev = skb->dev;
 	int res;
 
-	rtnl_lock();
-
-	/* check if ifdown occurred while schedule */
-	if (!netif_running(dev))
-		goto err_tx;
-
 	res = drv_xmit_sync(local, skb);
 	if (res)
 		goto err_tx;
@@ -53,14 +47,11 @@ void ieee802154_xmit_worker(struct work_struct *work)
 	dev->stats.tx_packets++;
 	dev->stats.tx_bytes += skb->len;
 
-	rtnl_unlock();
-
 	return;
 
 err_tx:
 	/* Restart the netif queue on each sub_if_data object. */
 	ieee802154_wake_queue(&local->hw);
-	rtnl_unlock();
 	kfree_skb(skb);
 	netdev_dbg(dev, "transmission failed\n");
 }
-- 
2.6.1


             reply	other threads:[~2015-12-09 22:15 UTC|newest]

Thread overview: 2+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2015-12-09 22:15 Alexander Aring [this message]
2015-12-09 22:18 ` [PATCH bluetooth] mac802154: tx: fix synced xmit deadlock Alexander Aring

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