daemon: debug segv correct use of dereferencing NULL.

[libguestfs.git] / daemon / debug.c

diff --git a/daemon/debug.c b/daemon/debug.c
index 31cef46..522012f 100644 (file)
--- 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;
 }