From: Richard W.M. Jones <rjones@redhat.com>
Date: Mon, 9 Jan 2012 16:55:49 +0000 (+0000)
Subject: daemon: debug segv correct use of dereferencing NULL.
X-Git-Url: http://git.annexia.org/?a=commitdiff_plain;ds=inline;p=libguestfs.git

daemon: debug segv correct use of dereferencing NULL.
---

diff --git a/daemon/debug.c b/daemon/debug.c
index 31cef46..522012f 100644
--- a/daemon/debug.c
+++ b/daemon/debug.c
@@ -198,7 +198,13 @@ debug_fds (const char *subcmd, int argc, char *const *const argv)
 static char *
 debug_segv (const char *subcmd, int argc, char *const *const argv)
 {
-  *(int*)0 = 0;
+  /* http://blog.llvm.org/2011/05/what-every-c-programmer-should-know.html
+   * "Dereferencing a NULL Pointer: contrary to popular belief,
+   * dereferencing a null pointer in C is undefined. It is not defined
+   * to trap [...]"
+   */
+  volatile int *ptr = NULL;
+  *ptr = 1;
   return NULL;
 }