IPoIB: Fix usage of uninitialized multicast objects

The driver should avoid calling ib_sa_free_multicast on the mcast->mc
object until it finishes its initialization state.  Otherwise we can
crash when ipoib_mcast_dev_flush() attempts to use the uninitialized
multicast object.

Instead, only call wait_for_completion() for multicast entries that
started the join process, meaning that ib_sa_join_multicast() finished.

Signed-off-by: Erez Shitrit <erezsh@mellanox.com>
Signed-off-by: Or Gerlitz <ogerlitz@mellanox.com>
Signed-off-by: Roland Dreier <roland@purestorage.com>

2 files changed, 19 insertions, 4 deletions

diff --git a/drivers/infiniband/ulp/ipoib/ipoib.h b/drivers/infiniband/ulp/ipoib/ipoib.h
index ec9190eff09c..c639f90cfda4 100644
--- a/drivers/infiniband/ulp/ipoib/ipoib.h
+++ b/drivers/infiniband/ulp/ipoib/ipoib.h
@@ -101,6 +101,7 @@ enum {
         IPOIB_MCAST_FLAG_SENDONLY = 1,
         IPOIB_MCAST_FLAG_BUSY     = 2,  /* joining or already joined */
         IPOIB_MCAST_FLAG_ATTACHED = 3,
+        IPOIB_MCAST_JOIN_STARTED  = 4,
 
         MAX_SEND_CQE              = 16,
         IPOIB_CM_COPYBREAK        = 256,
@@ -151,6 +152,7 @@ struct ipoib_mcast {
         struct sk_buff_head pkt_queue;
 
         struct net_device *dev;
+        struct completion done;
 };
 
 struct ipoib_rx_buf {
diff --git a/drivers/infiniband/ulp/ipoib/ipoib_multicast.c b/drivers/infiniband/ulp/ipoib/ipoib_multicast.c
index cecb98a4c662..780a2a0df41f 100644
--- a/drivers/infiniband/ulp/ipoib/ipoib_multicast.c
+++ b/drivers/infiniband/ulp/ipoib/ipoib_multicast.c
@@ -386,8 +386,10 @@ static int ipoib_mcast_join_complete(int status,
                         mcast->mcmember.mgid.raw, status);
 
         /* We trap for port events ourselves. */
-        if (status == -ENETRESET)
-                return 0;
+        if (status == -ENETRESET) {
+                status = 0;
+                goto out;
+        }
 
         if (!status)
                 status = ipoib_mcast_join_finish(mcast, &multicast->rec);
@@ -407,7 +409,8 @@ static int ipoib_mcast_join_complete(int status,
                 if (mcast == priv->broadcast)
                         queue_work(ipoib_workqueue, &priv->carrier_on_task);
 
-                return 0;
+                status = 0;
+                goto out;
         }
 
         if (mcast->logcount++ < 20) {
@@ -434,7 +437,8 @@ static int ipoib_mcast_join_complete(int status,
                                    mcast->backoff * HZ);
         spin_unlock_irq(&priv->lock);
         mutex_unlock(&mcast_mutex);
-
+out:
+        complete(&mcast->done);
         return status;
 }
 
@@ -484,11 +488,15 @@ static void ipoib_mcast_join(struct net_device *dev, struct ipoib_mcast *mcast,
         }
 
         set_bit(IPOIB_MCAST_FLAG_BUSY, &mcast->flags);
+        init_completion(&mcast->done);
+        set_bit(IPOIB_MCAST_JOIN_STARTED, &mcast->flags);
+
         mcast->mc = ib_sa_join_multicast(&ipoib_sa_client, priv->ca, priv->port,
                                          &rec, comp_mask, GFP_KERNEL,
                                          ipoib_mcast_join_complete, mcast);
         if (IS_ERR(mcast->mc)) {
                 clear_bit(IPOIB_MCAST_FLAG_BUSY, &mcast->flags);
+                complete(&mcast->done);
                 ret = PTR_ERR(mcast->mc);
                 ipoib_warn(priv, "ib_sa_join_multicast failed, status %d\n", ret);
 
@@ -751,6 +759,11 @@ void ipoib_mcast_dev_flush(struct net_device *dev)
 
         spin_unlock_irqrestore(&priv->lock, flags);
 
+        /* seperate between the wait to the leave*/
+        list_for_each_entry_safe(mcast, tmcast, &remove_list, list)
+                if (test_bit(IPOIB_MCAST_JOIN_STARTED, &mcast->flags))
+                        wait_for_completion(&mcast->done);
+
         list_for_each_entry_safe(mcast, tmcast, &remove_list, list) {
                 ipoib_mcast_leave(dev, mcast);
                 ipoib_mcast_free(mcast);