From 99fb853734cba8b778f9e60789ef51bd638d35da Mon Sep 17 00:00:00 2001
From: Ankit Meel <ankitm>
Date: Thu, 1 Oct 2020 14:47:13 +1000
Subject: Cleanup: avoid member access within null pointer

While harmless, UBSan warns about this.
Prefer offsetof where possible since it's more readable.
---
 intern/guardedalloc/intern/mallocn_guarded_impl.c | 3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)

(limited to 'intern')

diff --git a/intern/guardedalloc/intern/mallocn_guarded_impl.c b/intern/guardedalloc/intern/mallocn_guarded_impl.c
index 6c08cb3bb62..6a0d104d47d 100644
--- a/intern/guardedalloc/intern/mallocn_guarded_impl.c
+++ b/intern/guardedalloc/intern/mallocn_guarded_impl.c
@@ -24,6 +24,7 @@
  */
 
 #include <stdarg.h>
+#include <stddef.h> /* offsetof */
 #include <stdlib.h>
 #include <string.h> /* memcpy */
 #include <sys/types.h>
@@ -153,7 +154,7 @@ static const char *check_memlist(MemHead *memh);
 #define MEMTAG3 MAKE_ID('O', 'C', 'K', '!')
 #define MEMFREE MAKE_ID('F', 'R', 'E', 'E')
 
-#define MEMNEXT(x) ((MemHead *)(((char *)x) - ((char *)&(((MemHead *)0)->next))))
+#define MEMNEXT(x) ((MemHead *)(((char *)x) - offsetof(MemHead, next)))
 
 /* --------------------------------------------------------------------- */
 /* vars                                                                  */
-- 
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