linux-kernel - [PATCH] xen: fix upper bound of pmd loop in xen

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Date:	Thu, 23 Jun 2016 07:12:27 +0200
From:	Juergen Gross <jgross@...e.com>
To:	xen-devel@...ts.xenproject.org, linux-kernel@...r.kernel.org
Cc:	torvalds@...ux-foundation.org, boris.ostrovsky@...cle.com,
	david.vrabel@...rix.com, Juergen Gross <jgross@...e.com>
Subject: [PATCH] xen: fix upper bound of pmd loop in xen_cleanhighmap()

xen_cleanhighmap() is operating on level2_kernel_pgt only. The upper
bound of the loop setting non-kernel-image entries to zero should not
exceed the size of level2_kernel_pgt.

Reported-by: Linus Torvalds <torvalds@...ux-foundation.org>
Signed-off-by: Juergen Gross <jgross@...e.com>
---
 arch/x86/xen/mmu.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/arch/x86/xen/mmu.c b/arch/x86/xen/mmu.c
index 478a2de..2693b7e 100644
--- a/arch/x86/xen/mmu.c
+++ b/arch/x86/xen/mmu.c
@@ -1113,7 +1113,7 @@ static void __init xen_cleanhighmap(unsigned long vaddr,
 
 	/* NOTE: The loop is more greedy than the cleanup_highmap variant.
 	 * We include the PMD passed in on _both_ boundaries. */
-	for (; vaddr <= vaddr_end && (pmd < (level2_kernel_pgt + PAGE_SIZE));
+	for (; vaddr <= vaddr_end && (pmd < (level2_kernel_pgt + PTRS_PER_PMD));
 			pmd++, vaddr += PMD_SIZE) {
 		if (pmd_none(*pmd))
 			continue;
-- 
2.6.6