preproc: pp_cleanup -- Don't forget to zeroify variables

Once we free allocated memory don't forget to setup variables
to NULL, otherwise they are pointing into nonexisting memory,
which might lead into sigsegv in best case.

Signed-off-by: Cyrill Gorcunov <gorcunov@gmail.com>

1 files changed, 3 insertions, 0 deletions

diff --git a/preproc.c b/preproc.c
index 9b114c2e..12b39782 100644
--- a/preproc.c
+++ b/preproc.c
@@ -1184,6 +1184,7 @@ static void delete_Blocks(void)
         if (a != &blocks)
             nasm_free(a);
     }
+    memset(&blocks, 0, sizeof(blocks));
 }
 
 /*
@@ -5141,7 +5142,9 @@ static void pp_cleanup(int pass)
     if (pass == 0) {
         IncPath *i;
         free_llist(predef);
+        predef = NULL;
         delete_Blocks();
+        freeTokens = NULL;
         while ((i = ipath)) {
             ipath = i->next;
             if (i->path)