xbt_cfg_register(&_sg_cfg_set, "contexts/guard_size",
"Guard size for contexts stacks in memory pages",
xbt_cfgelm_int, 1, 1, _sg_cfg_cb_context_guard_size, NULL);
+#if defined(_XBT_WIN32) || (PTH_STACKGROWTH != -1)
+ xbt_cfg_setdefault_int(_sg_cfg_set, "contexts/guard_size", 0);
+#else
xbt_cfg_setdefault_int(_sg_cfg_set, "contexts/guard_size", 1);
+#endif
/* No, it was not set yet (the above setdefault() changed this to 1). */
smx_context_guard_size_was_set = 0;
{
void *stack;
- /* FIXME: current code for stack protection assumes that stacks are growing
- * downward (PTH_STACKGROWTH == -1). Protected pages need to be but after the
- * stack when PTH_STACKGROWTH == 1. */
+ /* FIXME: current code for stack overflow protection assumes that stacks are
+ * growing downward (PTH_STACKGROWTH == -1). Protected pages need to be put
+ * after the stack when PTH_STACKGROWTH == 1. */
if (smx_context_guard_size > 0 && !MC_is_active()) {
+
+#if defined(_XBT_WIN32) || (PTH_STACKGROWTH != -1)
+ static int warned_once = 0;
+ if (!warned_once) {
+ XBT_WARN("Stack overflow protection is known to be broken on your system. Either you're on Windows or PTH_STACKGROWTH != -1 (current value is %d).",
+ PTH_STACKGROWTH);
+ warned_once = 1;
+ }
+#endif
+
size_t size = smx_context_stack_size + smx_context_guard_size;
#ifdef HAVE_MC
/* Cannot use posix_memalign when HAVE_MC. Align stack by hand, and save the
char *alloc = xbt_malloc0(size + xbt_pagesize);
stack = alloc - ((uintptr_t)alloc & (xbt_pagesize - 1)) + xbt_pagesize;
*((void **)stack - 1) = alloc;
-#elif !defined(WIN32)
+#elif !defined(_XBT_WIN32)
if (posix_memalign(&stack, xbt_pagesize, size) != 0)
xbt_die("Failed to allocate stack.");
#else
- stack = _aligned_malloc(size, xbt_pagesize);
+ stack = _aligned_malloc(size, xbt_pagesize);
#endif
-#ifndef WIN32
+#ifndef _XBT_WIN32
if (mprotect(stack, smx_context_guard_size, PROT_NONE) == -1) {
XBT_WARN("Failed to protect stack: %s", strerror(errno));
/* That's not fatal, pursue anyway. */