x86/xen: panic on bad Xen-provided memory map

Panic if Xen provides a memory map with 0 entries. Although this is
unlikely, it is better to catch the error at the point of seeing the map
than later on as a symptom of some other crash.

Signed-off-by: Martin Kelly <martkell@amazon.com>
Signed-off-by: David Vrabel <david.vrabel@citrix.com>

diff --git a/arch/x86/xen/setup.c b/arch/x86/xen/setup.c
index af72161..29834b3 100644 (file)
--- a/arch/x86/xen/setup.c
+++ b/arch/x86/xen/setup.c
@@ -595,6 +595,7 @@ char * __init xen_memory_setup(void)
                rc = 0;
        }
        BUG_ON(rc);
+       BUG_ON(memmap.nr_entries == 0);
 
        /*
         * Xen won't allow a 1:1 mapping to be created to UNUSABLE