Patch "IB/mlx4: Fix potential deadlock when sending mad to wire" has been added to the 4.2-stable tree

Patch "IB/mlx4: Fix potential deadlock when sending mad to wire" has been added to the 4.2-stable tree

[gregkh]

This is a note to let you know that I've just added the patch titled

    IB/mlx4: Fix potential deadlock when sending mad to wire

to the 4.2-stable tree which can be found at:
    http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary

The filename of the patch is:
     ib-mlx4-fix-potential-deadlock-when-sending-mad-to-wire.patch
and it can be found in the queue-4.2 subdirectory.

If you, or anyone else, feels it should not be added to the stable tree,
please let <stable@vger.kernel.org> know about it.


>From 90c1d8b6350cca9d8a234f03c77a317a7613bcee Mon Sep 17 00:00:00 2001
From: Jack Morgenstein <jackm@dev.mellanox.co.il>
Date: Thu, 30 Jul 2015 17:34:21 +0300
Subject: IB/mlx4: Fix potential deadlock when sending mad to wire

From: Jack Morgenstein <jackm@dev.mellanox.co.il>

commit 90c1d8b6350cca9d8a234f03c77a317a7613bcee upstream.

send_mad_to_wire takes the same spinlock that is taken in
the interrupt context.  Therefore, it needs irqsave/restore.

Fixes: b9c5d6a64358 ('IB/mlx4: Add multicast group (MCG) paravirtualization for SR-IOV')
Signed-off-by: Jack Morgenstein <jackm@dev.mellanox.co.il>
Signed-off-by: Or Gerlitz <ogerlitz@mellanox.com>
Signed-off-by: Doug Ledford <dledford@redhat.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

---
 drivers/infiniband/hw/mlx4/mcg.c |    7 ++++---
 1 file changed, 4 insertions(+), 3 deletions(-)

--- a/drivers/infiniband/hw/mlx4/mcg.c
+++ b/drivers/infiniband/hw/mlx4/mcg.c
@@ -206,15 +206,16 @@ static int send_mad_to_wire(struct mlx4_
 {
 	struct mlx4_ib_dev *dev = ctx->dev;
 	struct ib_ah_attr	ah_attr;
+	unsigned long flags;
 
-	spin_lock(&dev->sm_lock);
+	spin_lock_irqsave(&dev->sm_lock, flags);
 	if (!dev->sm_ah[ctx->port - 1]) {
 		/* port is not yet Active, sm_ah not ready */
-		spin_unlock(&dev->sm_lock);
+		spin_unlock_irqrestore(&dev->sm_lock, flags);
 		return -EAGAIN;
 	}
 	mlx4_ib_query_ah(dev->sm_ah[ctx->port - 1], &ah_attr);
-	spin_unlock(&dev->sm_lock);
+	spin_unlock_irqrestore(&dev->sm_lock, flags);
 	return mlx4_ib_send_to_wire(dev, mlx4_master_func_num(dev->dev),
 				    ctx->port, IB_QPT_GSI, 0, 1, IB_QP1_QKEY,
 				    &ah_attr, NULL, mad);


Patches currently in stable-queue which might be from jackm@dev.mellanox.co.il are

queue-4.2/ib-mlx4-fix-potential-deadlock-when-sending-mad-to-wire.patch
queue-4.2/ib-mlx4-forbid-using-sysfs-to-change-roce-pkeys.patch