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: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Signed-off-by: Arnd Bergmann <arnd@arndb.de>
Signed-off-by: Ben Hutchings <ben@decadent.org.uk>

diff --git a/arch/x86/xen/mmu.c b/arch/x86/xen/mmu.c
index 16fb0099b7f295ed40c206e25478037f0b2ff651..f05f2d897a67c3c0db8eb3fdc17009de2b7495c8 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;