diff --git a/mm/page_alloc.c b/mm/page_alloc.c
index 9614aab..a40b2f1 100644
--- a/mm/page_alloc.c
+++ b/mm/page_alloc.c
@@ -247,13 +247,20 @@
 	int ret = 0;
 	unsigned seq;
 	unsigned long pfn = page_to_pfn(page);
+	unsigned long sp, start_pfn;
 
 	do {
 		seq = zone_span_seqbegin(zone);
+		start_pfn = zone->zone_start_pfn;
+		sp = zone->spanned_pages;
 		if (!zone_spans_pfn(zone, pfn))
 			ret = 1;
 	} while (zone_span_seqretry(zone, seq));
 
+	if (ret)
+		pr_err("page %lu outside zone [ %lu - %lu ]\n",
+			pfn, start_pfn, start_pfn + sp);
+
 	return ret;
 }