1 files changed, 16 insertions, 0 deletions

diff --git a/drivers/xen/balloon.c b/drivers/xen/balloon.c
index 9781e0dd59d6..d46839f51e73 100644
--- a/drivers/xen/balloon.c
+++ b/drivers/xen/balloon.c
@@ -151,6 +151,8 @@ static DECLARE_WAIT_QUEUE_HEAD(balloon_wq);
 static void balloon_process(struct work_struct *work);
 static DECLARE_DELAYED_WORK(balloon_worker, balloon_process);
 
+static void release_memory_resource(struct resource *resource);
+
 /* When ballooning out (allocating memory to return to Xen) we don't really
    want the kernel to try too hard since that can trigger the oom killer. */
 #define GFP_BALLOON \
@@ -267,6 +269,20 @@ static struct resource *additional_memory_resource(phys_addr_t size)
                 return NULL;
         }
 
+#ifdef CONFIG_SPARSEMEM
+        {
+                unsigned long limit = 1UL << (MAX_PHYSMEM_BITS - PAGE_SHIFT);
+                unsigned long pfn = res->start >> PAGE_SHIFT;
+
+                if (pfn > limit) {
+                        pr_err("New System RAM resource outside addressable RAM (%lu > %lu)\n",
+                               pfn, limit);
+                        release_memory_resource(res);
+                        return NULL;
+                }
+        }
+#endif
+
         return res;
 }