x86/xen: fix upper bound of pmd loop in xen_cleanhighmap()

commit 1cf38741308c64d08553602b3374fb39224eeb5a upstream.

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@linux-foundation.org>
Signed-off-by: Juergen Gross <jgross@suse.com>
Signed-off-by: David Vrabel <david.vrabel@citrix.com>
Signed-off-by: Willy Tarreau <w@1wt.eu>

diff --git a/arch/x86/xen/mmu.c b/arch/x86/xen/mmu.c
index fdc3ba28ca38d2a89eb3e59e6bca73b692f84945..53b061c9ad7e18aea82e2bb17819ff0a111c8b3e 100644 (file)
--- a/arch/x86/xen/mmu.c
+++ b/arch/x86/xen/mmu.c
@@ -1187,7 +1187,7 @@ 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;