From: Jeremy Fitzhardinge <jeremy@goop.org>
Date: Mon, 17 Nov 2008 17:35:00 +0000 (-0800)
Subject: xen: fix scrub_page()
X-Git-Url: https://git.stricted.de/?a=commitdiff_plain;h=26a3e99160cfb06a0a33e25b9fb0d516e2cc680d;p=GitHub%2FLineageOS%2Fandroid_kernel_samsung_universal7580.git

xen: fix scrub_page()

Impact: fix guest kernel crash with CONFIG_XEN_SCRUB_PAGES=y

Jens noticed that scrub_page() has a buggy unmap of the wrong
thing. (virtual address instead of page)

Linus pointed out that the whole scrub_page() code is an unnecessary
reimplementation of clear_highpage() to begin with.

Just use clear_highpage() rather than reimplementing it poorly.

Reported-by: Jens Axboe <jens.axboe@oracle.com>
Signed-off-by: Jeremy Fitzhardinge <jeremy.fitzhardinge@citrix.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
---

diff --git a/drivers/xen/balloon.c b/drivers/xen/balloon.c
index a0fb5eac407..526c191e84e 100644
--- a/drivers/xen/balloon.c
+++ b/drivers/xen/balloon.c
@@ -122,14 +122,7 @@ static struct timer_list balloon_timer;
 static void scrub_page(struct page *page)
 {
 #ifdef CONFIG_XEN_SCRUB_PAGES
-	if (PageHighMem(page)) {
-		void *v = kmap(page);
-		clear_page(v);
-		kunmap(v);
-	} else {
-		void *v = page_address(page);
-		clear_page(v);
-	}
+	clear_highpage(page);
 #endif
 }