From f33d653f46f5889db7be4fef31d71bc871834c10 Mon Sep 17 00:00:00 2001 From: Jan Beulich Date: Tue, 28 Nov 2017 13:14:10 +0100 Subject: [PATCH] x86: replace bad ASSERT() in xenmem_add_to_physmap_one() There are no locks being held, i.e. it is possible to be triggered by racy hypercall invocations. Subsequent code doesn't really depend on the checked values, so this is not a security issue. Signed-off-by: Jan Beulich Acked-by: Andrew Cooper Acked-by: George Dunlap Release-acked-by: Julien Grall --- xen/arch/x86/mm.c | 8 ++++++-- 1 file changed, 6 insertions(+), 2 deletions(-) diff --git a/xen/arch/x86/mm.c b/xen/arch/x86/mm.c index 886a5ee327..86c822d577 100644 --- a/xen/arch/x86/mm.c +++ b/xen/arch/x86/mm.c @@ -4143,8 +4143,12 @@ int xenmem_add_to_physmap_one( /* Unmap from old location, if any. */ old_gpfn = get_gpfn_from_mfn(mfn_x(mfn)); ASSERT( old_gpfn != SHARED_M2P_ENTRY ); - if ( space == XENMAPSPACE_gmfn || space == XENMAPSPACE_gmfn_range ) - ASSERT( old_gpfn == gfn ); + if ( (space == XENMAPSPACE_gmfn || space == XENMAPSPACE_gmfn_range) && + old_gpfn != gfn ) + { + rc = -EXDEV; + goto put_both; + } if ( old_gpfn != INVALID_M2P_ENTRY ) rc = guest_physmap_remove_page(d, _gfn(old_gpfn), mfn, PAGE_ORDER_4K); -- 2.39.5