Fix segv in reloc.c

diff --git a/lib/relocator.c b/lib/relocator.c
index e43463e4d7436fedbea85921f080a98440c85f87..eac290c97c68988fae9629ca9c93a3a8a61ac29c 100644 (file)
--- a/lib/relocator.c
+++ b/lib/relocator.c
@@ -957,7 +957,8 @@ malloc_in_range (struct grub_relocator *rel,
                        ne->end = alloc_end;
                        ne->next = extra_blocks;
                        ne->prev = &extra_blocks;
-                       extra_blocks->prev = &(ne->next);
+                       if (extra_blocks)
+                         extra_blocks->prev = &(ne->next);
                        extra_blocks = ne;
                        curschu->extra = ne;
                      }