From 9acf6a8570dcfc9f55724b8b71099fc8768e8c26 Mon Sep 17 00:00:00 2001 From: "Michael S. Tsirkin" Date: Thu, 2 Mar 2006 11:07:47 -0800 Subject: [PATCH] IPoIB: Fix multicast race between canceling and completing ipoib_mcast_stop_thread currently tests mcast->query and if it is NULL, does not perform wait_for_completion on the mcast and frees the mcast object directly. However, since both operations are done without locking, it is possible that ipoib_mcast_join_complete is in progress on this mcast object and has set mcast->query to NULL already. Solve this by: - taking priv->lock before we change mcast->query in ipoib_mcast_join_complete, and keeping it until we no longer need the mcast object - taking priv->lock around mcast->query test in ipoib_mcast_stop_thread Signed-off-by: Michael S. Tsirkin Signed-off-by: Roland Dreier --- drivers/infiniband/ulp/ipoib/ipoib_multicast.c | 15 ++++++++++++--- 1 file changed, 12 insertions(+), 3 deletions(-) diff --git a/drivers/infiniband/ulp/ipoib/ipoib_multicast.c b/drivers/infiniband/ulp/ipoib/ipoib_multicast.c index e5dc2a0345..fde442a199 100644 --- a/drivers/infiniband/ulp/ipoib/ipoib_multicast.c +++ b/drivers/infiniband/ulp/ipoib/ipoib_multicast.c @@ -437,9 +437,11 @@ static void ipoib_mcast_join_complete(int status, if (mcast->backoff > IPOIB_MAX_BACKOFF_SECONDS) mcast->backoff = IPOIB_MAX_BACKOFF_SECONDS; + mutex_lock(&mcast_mutex); + + spin_lock_irq(&priv->lock); mcast->query = NULL; - mutex_lock(&mcast_mutex); if (test_bit(IPOIB_MCAST_RUN, &priv->flags)) { if (status == -ETIMEDOUT) queue_work(ipoib_workqueue, &priv->mcast_task); @@ -448,6 +450,7 @@ static void ipoib_mcast_join_complete(int status, mcast->backoff * HZ); } else complete(&mcast->done); + spin_unlock_irq(&priv->lock); mutex_unlock(&mcast_mutex); return; @@ -635,21 +638,27 @@ int ipoib_mcast_stop_thread(struct net_device *dev, int flush) if (flush) flush_workqueue(ipoib_workqueue); + spin_lock_irq(&priv->lock); if (priv->broadcast && priv->broadcast->query) { ib_sa_cancel_query(priv->broadcast->query_id, priv->broadcast->query); priv->broadcast->query = NULL; + spin_unlock_irq(&priv->lock); ipoib_dbg_mcast(priv, "waiting for bcast\n"); wait_for_completion(&priv->broadcast->done); - } + } else + spin_unlock_irq(&priv->lock); list_for_each_entry(mcast, &priv->multicast_list, list) { + spin_lock_irq(&priv->lock); if (mcast->query) { ib_sa_cancel_query(mcast->query_id, mcast->query); mcast->query = NULL; + spin_unlock_irq(&priv->lock); ipoib_dbg_mcast(priv, "waiting for MGID " IPOIB_GID_FMT "\n", IPOIB_GID_ARG(mcast->mcmember.mgid)); wait_for_completion(&mcast->done); - } + } else + spin_unlock_irq(&priv->lock); } return 0; -- 2.39.5