Patch "xen/xenbus: Don't leak memory when unmapping the ring on HVM backend" has been added to the 4.1-stable tree

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

    xen/xenbus: Don't leak memory when unmapping the ring on HVM backend

to the 4.1-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:
     xen-xenbus-don-t-leak-memory-when-unmapping-the-ring-on-hvm-backend.patch
and it can be found in the queue-4.1 subdirectory.

If you, or anyone else, feels it should not be added to the stable tree,
please let [off-list ref] know about it.

From c22fe519e7e2b94ad173e0ea3b89c1a7d8be8d00 Mon Sep 17 00:00:00 2001

From: Julien Grall <redacted>
Date: Mon, 10 Aug 2015 19:10:38 +0100
Subject: xen/xenbus: Don't leak memory when unmapping the ring on HVM backend

From: Julien Grall <redacted>

commit c22fe519e7e2b94ad173e0ea3b89c1a7d8be8d00 upstream.

The commit ccc9d90a9a8b5c4ad7e9708ec41f75ff9e98d61d "xenbus_client:
Extend interface to support multi-page ring" removes the call to
free_xenballooned_pages() in xenbus_unmap_ring_vfree_hvm(), leaking a
page for every shared ring.

Only with backends running in HVM domains were affected.

Signed-off-by: Julien Grall <redacted>
Reviewed-by: Boris Ostrovsky <boris.ostrovsky@oracle.com>
Reviewed-by: Wei Liu <redacted>
Signed-off-by: David Vrabel <redacted>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

---
 drivers/xen/xenbus/xenbus_client.c |    4 +++-
 1 file changed, 3 insertions(+), 1 deletion(-)

--- a/drivers/xen/xenbus/xenbus_client.c
+++ b/drivers/xen/xenbus/xenbus_client.c

@@ -814,8 +814,10 @@ static int xenbus_unmap_ring_vfree_hvm(s
 
 	rv = xenbus_unmap_ring(dev, node->handles, node->nr_handles,
 			       addrs);
-	if (!rv)
+	if (!rv) {
 		vunmap(vaddr);
+		free_xenballooned_pages(node->nr_handles, node->hvm.pages);
+	}
 	else
 		WARN(1, "Leaking %p, size %u page(s)\n", vaddr,
 		     node->nr_handles);

Patches currently in stable-queue which might be from julien.grall@citrix.com are

queue-4.1/xen-xenbus-don-t-leak-memory-when-unmapping-the-ring-on-hvm-backend.patch