[Xen-devel] [PATCH 1/2] x86: make sure module array is large enough in pvh-boot.c

[Wei Liu <wei.liu2@xxxxxxxxxx>]

The relocation code in __start_xen requires one extra element in the
module array. By the looks of it the temporary array is already large
enough. Add a BUG_ON to catch any issue in the future.

While at it, turn another ASSERT to BUG_ON as well.

Signed-off-by: Wei Liu <wei.liu2@xxxxxxxxxx>
---
 xen/arch/x86/guest/pvh-boot.c | 9 ++++++++-
 1 file changed, 8 insertions(+), 1 deletion(-)

diff --git a/xen/arch/x86/guest/pvh-boot.c b/xen/arch/x86/guest/pvh-boot.c
index 0e9e5bfdf6..2e103105fa 100644
--- a/xen/arch/x86/guest/pvh-boot.c
+++ b/xen/arch/x86/guest/pvh-boot.c
@@ -42,7 +42,14 @@ static void __init convert_pvh_info(void)
     module_t *mod;
     unsigned int i;
 
-    ASSERT(pvh_info->magic == XEN_HVM_START_MAGIC_VALUE);
+    BUG_ON(pvh_info->magic != XEN_HVM_START_MAGIC_VALUE);
+
+    /*
+     * Temporary module array needs to be at least one element bigger than
+     * required. The extra element is used to aid relocation. See
+     * arch/x86/setup.c:__start_xen().
+     */
+    BUG_ON(ARRAY_SIZE(pvh_mbi_mods) <= pvh_info->nr_modules);
 
     /*
      * Turn hvm_start_info into mbi. Luckily all modules are placed under 4GB
-- 
2.11.0


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