From: "U.Nakamura" <usa@...>
Date: 2010-07-16T12:57:36+09:00
Subject: [ruby-core:31307] Re: [Bug #3523][Assigned] win32 exception c0000029 on exit using fibers

Hello,

> http://redmine.ruby-lang.org/issues/show/3523

Interim report:

There is a patch for ruby_1_9_2, to save and restore SEH frame.
After this patch is applied, Bill's 0xC0000029 error vanishes!

... But another error 0xC0000374 occurs.
This error means heap corruption.
I cannot confirm yet whether this error is due to ruby or EventMachine.

Index: cont.c
===================================================================
--- cont.c	(revision 28653)
+++ cont.c	(working copy)
@@ -39,6 +39,9 @@ typedef struct rb_context_struct {
     VALUE *machine_register_stack_src;
     int machine_register_stack_size;
 #endif
+#if _WIN32 && (defined(_M_IX86) || defined(__i386__))
+    VALUE win32_exception_list;
+#endif
     rb_thread_t saved_thread;
     rb_jmpbuf_t jmpbuf;
     size_t machine_stack_size;
@@ -224,6 +227,44 @@ fiber_memsize(const void *ptr)
     return 0;
 }
 
+#if _WIN32 && (defined(_M_IX86) || defined(__i386__))
+static inline VALUE
+win32_get_exception_list(void)
+{
+    VALUE p;
+# if defined _MSC_VER
+#   ifdef _M_IX86
+#   if _MSC_VER >= 1310
+      /* warning: unsafe assignment to fs:0 ... this is ok */
+#     pragma warning(disable: 4733)
+#   endif
+    __asm mov eax, fs:[0];
+    __asm mov p, eax;
+#   endif
+# elif defined __GNUC__
+#   ifdef __i386__
+    __asm__("movl %%fs:0,%0" : "=r"(p));
+#   endif
+# endif
+    return p;
+}
+
+static inline void
+win32_set_exception_list(VALUE p)
+{
+# if defined _MSC_VER
+#   ifdef _M_IX86
+    __asm mov eax, p;
+    __asm mov fs:[0], eax;
+#   endif
+# elif defined __GNUC__
+#   ifdef __i386__
+    __asm__("movl %0,%%fs:0" :: "r"(p));
+#   endif
+# endif
+}
+#endif
+
 static void
 cont_save_machine_stack(rb_thread_t *th, rb_context_t *cont)
 {
@@ -267,6 +308,9 @@ cont_save_machine_stack(rb_thread_t *th,
 
     MEMCPY(cont->machine_register_stack, cont->machine_register_stack_src, VALUE, size);
 #endif
+#if _WIN32 && (defined(_M_IX86) || defined(__i386__))
+    cont->win32_exception_list = win32_get_exception_list();
+#endif
 
     sth->machine_stack_start = sth->machine_stack_end = 0;
 #ifdef __ia64
@@ -403,6 +447,9 @@ cont_restore_1(rb_context_t *cont)
     }
 #endif
     if (cont->machine_stack_src) {
+#if _WIN32 && (defined(_M_IX86) || defined(__i386__))
+	win32_set_exception_list(cont->win32_exception_list);
+#endif
 	FLUSH_REGISTER_WINDOWS;
 	MEMCPY(cont->machine_stack_src, cont->machine_stack,
 	       VALUE, cont->machine_stack_size);

Regards,
-- 
U.Nakamura <usa@garbagecollect.jp>