From: Andrew Cooper <andrew.cooper3@citrix.com>
Date: Mon, 9 Dec 2013 13:13:23 +0000 (+0100)
Subject: defer the domain mapping in scrub_one_page()
X-Git-Tag: archive/raspbian/4.8.0-1+rpi1~1^2~5795
X-Git-Url: https://dgit.raspbian.org/?a=commitdiff_plain;h=7dd4f9da063cb2cd43426c785535534c9d958ce5;p=xen.git

defer the domain mapping in scrub_one_page()

This avoids a resource leak and needless playing with the pagetables in the
case that the page is broken.

Signed-off-by: Andrew Cooper <andrew.cooper3@citrix.com>
Reviewed-by: Jan Beulich <JBeulich@suse.com>
Reviewed-by: Keir Fraser <keir@xen.org>
---

diff --git a/xen/common/page_alloc.c b/xen/common/page_alloc.c
index 8002bd2517..5f484a2ecc 100644
--- a/xen/common/page_alloc.c
+++ b/xen/common/page_alloc.c
@@ -1652,11 +1652,13 @@ __initcall(pagealloc_keyhandler_init);
 
 void scrub_one_page(struct page_info *pg)
 {
-    void *p = __map_domain_page(pg);
+    void *p;
 
     if ( unlikely(pg->count_info & PGC_broken) )
         return;
 
+    p = __map_domain_page(pg);
+
 #ifndef NDEBUG
     /* Avoid callers relying on allocations returning zeroed pages. */
     memset(p, 0xc2, PAGE_SIZE);