FAILED: patch "[PATCH] x86/xen: Do not clip xen_e820_map to xen_e820_map_entries" failed to apply to 4.2-stable tree

[<gregkh@linuxfoundation.org>]

The patch below does not apply to the 4.2-stable tree.
If someone wants it applied there, or to any other stable or longterm
tree, then please email the backport, including the original git commit
id to <stable@vger.kernel.org>.

thanks,

greg k-h

------------------ original commit in Linus's tree ------------------

>From 64c98e7f49100b637cd20a6c63508caed6bbba7a Mon Sep 17 00:00:00 2001
From: Malcolm Crossley <malcolm.crossley@citrix.com>
Date: Mon, 28 Sep 2015 11:36:52 +0100
Subject: [PATCH] x86/xen: Do not clip xen_e820_map to xen_e820_map_entries
 when sanitizing map

Sanitizing the e820 map may produce extra E820 entries which would result in
the topmost E820 entries being removed. The removed entries would typically
include the top E820 usable RAM region and thus result in the domain having
signicantly less RAM available to it.

Fix by allowing sanitize_e820_map to use the full size of the allocated E820
array.

Signed-off-by: Malcolm Crossley <malcolm.crossley@citrix.com>
Reviewed-by: Boris Ostrovsky <boris.ostrovsky@oracle.com>
Cc: <stable@vger.kernel.org>
Signed-off-by: David Vrabel <david.vrabel@citrix.com>

diff --git a/arch/x86/xen/setup.c b/arch/x86/xen/setup.c
index 4ebfcecc2a8b..1c30e4ab1022 100644
--- a/arch/x86/xen/setup.c
+++ b/arch/x86/xen/setup.c
@@ -798,7 +798,7 @@ char * __init xen_memory_setup(void)
 		xen_ignore_unusable();
 
 	/* Make sure the Xen-supplied memory map is well-ordered. */
-	sanitize_e820_map(xen_e820_map, xen_e820_map_entries,
+	sanitize_e820_map(xen_e820_map, ARRAY_SIZE(xen_e820_map),
 			  &xen_e820_map_entries);
 
 	max_pages = xen_get_max_pages();