IB/ipoib: Update broadcast object if PKey value was changed in index 0

From: Feras Daoud <ferasda-VPRAkNaXOzVWk0Htik3J/[email protected]>

Update the broadcast address in the priv->broadcast object when the Pkey value changes in index 0, otherwise the multicast GID value will keep the previous value of the PKey, and will not be updated. This leads to interface state down because the interface will keep the old PKey value.

For example, in SR-IOV environment, if the PF changes the value of PKey index 0 for one of the VFs, then the VF receives PKey change event that triggers heavy flush. This flush calls update_parent_pkey that update the broadcast object and its relevant members. If in this case the multicast GID will not be updated, the interface state will be down.

---
 drivers/infiniband/ulp/ipoib/ipoib_ib.c | 13 +++++++++++++
 1 file changed, 13 insertions(+)

index 12c4f84a6639..4c80681922c5 100644
@@ -967,6 +967,19 @@ static inline int update_parent_pkey(struct ipoib_dev_priv *priv)
 		 */
 		priv->dev->broadcast[8] = priv->pkey >> 8;
 		priv->dev->broadcast[9] = priv->pkey & 0xff;
+
+		/*
+		 * Update the broadcast address in the priv->broadcast object,
+		 * in case it already exists, otherwise no one will do that.
+		 */
+		if (priv->broadcast) {
+			spin_lock_irq(&priv->lock);
+			memcpy(priv->broadcast->mcmember.mgid.raw,
+			       priv->dev->broadcast + 4,
+			sizeof(union ib_gid));
+			spin_unlock_irq(&priv->lock);
+		}
+
 		return 0;
 	}
 

2.12.0

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From: Feras Daoud <ferasda-VPRAkNaXOzVWk0Htik3J/[email protected]>

Before calling ipoib_stop, rtnl_lock should be taken, then the flow clears the IPOIB_FLAG_ADMIN_UP and IPOIB_FLAG_OPER_UP flags, and waits for mcast completion if IPOIB_MCAST_FLAG_BUSY is set.

On the other hand, the flow of multicast join task initializes a mcast completion, sets the IPOIB_MCAST_FLAG_BUSY and calls ipoib_mcast_join. If IPOIB_FLAG_OPER_UP flag is not set, this call returns EINVAL without setting the mcast completion and leads to a deadlock.

    ipoib_stop                          |
        |                               |
    clear_bit(IPOIB_FLAG_ADMIN_UP)      |
        |                               |
    Context Switch                      |
        |                       ipoib_mcast_join_task
        |                               |
        |                       spin_lock_irq(lock)
        |                               |
        |                       init_completion(mcast)
        |                               |
        |                       set_bit(IPOIB_MCAST_FLAG_BUSY)
        |                               |
        |                       Context Switch
        |                               |
    clear_bit(IPOIB_FLAG_OPER_UP)       |
        |                               |
    spin_lock_irqsave(lock)             |
        |                               |
    Context Switch                      |
        |                       ipoib_mcast_join
        |                       return (-EINVAL)
        |                               |
        |                       spin_unlock_irq(lock)
        |                               |
        |                       Context Switch
        |                               |

ipoib_mcast_dev_flush |
wait_for_completion(mcast) |

ipoib_stop will wait for mcast completion for ever, and will not release the rtnl_lock. As a result panic occurs with the following trace:

    [13441.639268] Call Trace:
    [13441.640150]  [<ffffffff8168b579>] schedule+0x29/0x70
    [13441.641038]  [<ffffffff81688fc9>] schedule_timeout+0x239/0x2d0
    [13441.641914]  [<ffffffff810bc017>] ? complete+0x47/0x50
    [13441.642765]  [<ffffffff810a690d>] ? flush_workqueue_prep_pwqs+0x16d/0x200
    [13441.643580]  [<ffffffff8168b956>] wait_for_completion+0x116/0x170
    [13441.644434]  [<ffffffff810c4ec0>] ? wake_up_state+0x20/0x20
    [13441.645293]  [<ffffffffa05af170>] ipoib_mcast_dev_flush+0x150/0x190 [ib_ipoib]
    [13441.646159]  [<ffffffffa05ac967>] ipoib_ib_dev_down+0x37/0x60 [ib_ipoib]
    [13441.647013]  [<ffffffffa05a4805>] ipoib_stop+0x75/0x150 [ib_ipoib]

---
 drivers/infiniband/ulp/ipoib/ipoib_multicast.c | 11 +++++------
 1 file changed, 5 insertions(+), 6 deletions(-)

index 69e146cdc306..01c6e5595612 100644
@@ -489,6 +489,9 @@ static int ipoib_mcast_join(struct net_device *dev, struct ipoib_mcast *mcast)
 	    !test_bit(IPOIB_FLAG_OPER_UP, &priv->flags))
 		return -EINVAL;
 
+	init_completion(&mcast->done);
+	set_bit(IPOIB_MCAST_FLAG_BUSY, &mcast->flags);
+
 	ipoib_dbg_mcast(priv, "joining MGID %pI6\n", mcast->mcmember.mgid.raw);
 
 	rec.mgid     = mcast->mcmember.mgid;

@@ -647,8 +650,6 @@ void ipoib_mcast_join_task(struct work_struct *work)
 			if (mcast->backoff == 1 ||
 			    time_after_eq(jiffies, mcast->delay_until)) {
 				/* Found the next unjoined group */
-				init_completion(&mcast->done);
-				set_bit(IPOIB_MCAST_FLAG_BUSY, &mcast->flags);
 				if (ipoib_mcast_join(dev, mcast)) {
 					spin_unlock_irq(&priv->lock);
 					return;

@@ -668,11 +669,9 @@ void ipoib_mcast_join_task(struct work_struct *work)
 		queue_delayed_work(priv->wq, &priv->mcast_task,
 				   delay_until - jiffies);
 	}
-	if (mcast) {
-		init_completion(&mcast->done);
-		set_bit(IPOIB_MCAST_FLAG_BUSY, &mcast->flags);
+	if (mcast)
 		ipoib_mcast_join(dev, mcast);
-	}
+
 	spin_unlock_irq(&priv->lock);
 }
 

2.12.0

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Thanks, applied.

Doug Ledford <[email protected]>
    GPG KeyID: B826A3330E572FDD
   
Key fingerprint = AE6B 1BDA 122B 23B4 265B  1274 B826 A333 0E57 2FDD

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Thanks, applied.

Doug Ledford <[email protected]>
    GPG KeyID: B826A3330E572FDD
   
Key fingerprint = AE6B 1BDA 122B 23B4 265B  1274 B826 A333 0E57 2FDD

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