From a77a57a1a22afc31891d95879fe3cf2ab03838b0 Mon Sep 17 00:00:00 2001 From: Roland Dreier Date: Tue, 19 Aug 2008 15:01:32 -0700 Subject: IPoIB: Fix deadlock on RTNL in ipoib_stop() Commit c8c2afe3 ("IPoIB: Use rtnl lock/unlock when changing device flags") added a call to rtnl_lock() in ipoib_mcast_join_task(), which is run from the ipoib_workqueue. However, ipoib_stop() (which is run inside rtnl_lock()) flushes this workqueue, which leads to a deadlock if the join task is pending. Fix this by simply not flushing the workqueue from ipoib_stop(). It turns out that we really don't care about workqueue tasks running during or after ipoib_stop(), as long as we make sure to flush the workqueue before unregistering a netdev. This fixes . Signed-off-by: Roland Dreier --- drivers/infiniband/ulp/ipoib/ipoib_multicast.c | 10 +++++++++- 1 file changed, 9 insertions(+), 1 deletion(-) (limited to 'drivers/infiniband/ulp/ipoib/ipoib_multicast.c') diff --git a/drivers/infiniband/ulp/ipoib/ipoib_multicast.c b/drivers/infiniband/ulp/ipoib/ipoib_multicast.c index 8950e9546f4..ac33c8f3ea8 100644 --- a/drivers/infiniband/ulp/ipoib/ipoib_multicast.c +++ b/drivers/infiniband/ulp/ipoib/ipoib_multicast.c @@ -392,8 +392,16 @@ static int ipoib_mcast_join_complete(int status, &priv->mcast_task, 0); mutex_unlock(&mcast_mutex); - if (mcast == priv->broadcast) + if (mcast == priv->broadcast) { + /* + * Take RTNL lock here to avoid racing with + * ipoib_stop() and turning the carrier back + * on while a device is being removed. + */ + rtnl_lock(); netif_carrier_on(dev); + rtnl_unlock(); + } return 0; } -- cgit v1.2.3