diff -pruN glibc-2.17-c758a686/nptl/sysdeps/pthread/unwind-forcedunwind.c glibc-2.17-c758a686/nptl/sysdeps/pthread/unwind-forcedunwind.c

--- glibc-2.17-c758a686/nptl/sysdeps/pthread/unwind-forcedunwind.c	2010-05-04 16:57:23.000000000 +0530

+++ glibc-2.17-c758a686/nptl/sysdeps/pthread/unwind-forcedunwind.c	2014-06-02 23:00:02.901013275 +0530

@@ -45,8 +45,10 @@ pthread_cancel_init (void)

   if (__builtin_expect (libgcc_s_handle != NULL, 1))

     {

-      /* Force gcc to reload all values.  */

-      asm volatile ("" ::: "memory");

+      /* Order reads so as to prevent speculation of loads

+	 of libgcc_s_{resume,personality,forcedunwind,getcfa}

+	 to points prior to the write barrier.  */

+      atomic_read_barrier ();

       return;

     }

@@ -72,9 +74,14 @@ pthread_cancel_init (void)

   libgcc_s_forcedunwind = forcedunwind;

   PTR_MANGLE (getcfa);

   libgcc_s_getcfa = getcfa;

-  /* Make sure libgcc_s_handle is written last.  Otherwise,

-     pthread_cancel_init might return early even when the pointer the

-     caller is interested in is not initialized yet.  */

+  /* At the point at which any thread writes the handle

+     to libgcc_s_handle, the initialization is complete.

+     The writing of libgcc_s_handle is atomic. All other

+     threads reading libgcc_s_handle do so atomically. Any

+     thread that does not execute this function must issue

+     a read barrier to ensure that all of the above has

+     actually completed and that the values of the

+     function pointers are correct.   */

   atomic_write_barrier ();

   libgcc_s_handle = handle;

 }

@@ -91,13 +98,19 @@ __unwind_freeres (void)

     }

 }

-void

-_Unwind_Resume (struct _Unwind_Exception *exc)

+static __always_inline void

+_maybe_pthread_cancel_init (void)

 {

   if (__builtin_expect (libgcc_s_handle == NULL, 0))

     pthread_cancel_init ();

   else

     atomic_read_barrier ();

+}

+

+void

+_Unwind_Resume (struct _Unwind_Exception *exc)

+{

+  _maybe_pthread_cancel_init ();

   void (*resume) (struct _Unwind_Exception *exc) = libgcc_s_resume;

   PTR_DEMANGLE (resume);

@@ -108,10 +123,7 @@ __gcc_personality_v0 (int version, _Unwi

 		      struct _Unwind_Exception *ue_header,

 		      struct _Unwind_Context *context)

 {

-  if (__builtin_expect (libgcc_s_handle == NULL, 0))

-    pthread_cancel_init ();

-  else

-    atomic_read_barrier ();

+  _maybe_pthread_cancel_init ();

   _Unwind_Reason_Code (*personality)

     (int, _Unwind_Action, _Unwind_Exception_Class, struct _Unwind_Exception *,

@@ -122,10 +136,7 @@ _Unwind_Reason_Code

 _Unwind_ForcedUnwind (struct _Unwind_Exception *exc, _Unwind_Stop_Fn stop,

 		      void *stop_argument)

 {

-  if (__builtin_expect (libgcc_s_handle == NULL, 0))

-    pthread_cancel_init ();

-  else

-    atomic_read_barrier ();

+  _maybe_pthread_cancel_init ();

   _Unwind_Reason_Code (*forcedunwind)

     (struct _Unwind_Exception *, _Unwind_Stop_Fn, void *)

@@ -135,10 +148,7 @@ _Unwind_ForcedUnwind (struct _Unwind_Exc

 _Unwind_Word

 _Unwind_GetCFA (struct _Unwind_Context *context)

 {

-  if (__builtin_expect (libgcc_s_handle == NULL, 0))

-    pthread_cancel_init ();

-  else

-    atomic_read_barrier ();

+  _maybe_pthread_cancel_init ();

   _Unwind_Word (*getcfa) (struct _Unwind_Context *) = libgcc_s_getcfa;

   PTR_DEMANGLE (getcfa);

diff -pruN glibc-2.17-c758a686/sysdeps/gnu/unwind-resume.c glibc-2.17-c758a686/sysdeps/gnu/unwind-resume.c

--- glibc-2.17-c758a686/sysdeps/gnu/unwind-resume.c	2010-05-04 16:57:23.000000000 +0530

+++ glibc-2.17-c758a686/sysdeps/gnu/unwind-resume.c	2014-06-02 23:02:26.812007078 +0530

@@ -20,8 +20,11 @@

 #include <dlfcn.h>

 #include <stdio.h>

 #include <unwind.h>

+#include <pthreadP.h>

+#include <sysdep.h>

 #include <gnu/lib-names.h>

+static void *libgcc_s_handle;

 static void (*libgcc_s_resume) (struct _Unwind_Exception *exc);

 static _Unwind_Reason_Code (*libgcc_s_personality)

   (int, _Unwind_Action, _Unwind_Exception_Class, struct _Unwind_Exception *,

@@ -42,13 +45,32 @@ init (void)

   libgcc_s_resume = resume;

   libgcc_s_personality = personality;

+  atomic_write_barrier ();

+  /* At the point at which any thread writes the handle

+     to libgcc_s_handle, the initialization is complete.

+     The writing of libgcc_s_handle is atomic. All other

+     threads reading libgcc_s_handle do so atomically. Any

+     thread that does not execute this function must issue

+     a read barrier to ensure that all of the above has

+     actually completed and that the values of the

+     function pointers are correct.   */

+  libgcc_s_handle = handle;

 }

+static __always_inline void

+_maybe_init (void)

+{

+  if (__builtin_expect (libgcc_s_handle == NULL, 0))

+    init ();

+  else

+    atomic_read_barrier ();

+}

+

+

 void

 _Unwind_Resume (struct _Unwind_Exception *exc)

 {

-  if (__builtin_expect (libgcc_s_resume == NULL, 0))

-    init ();

+  _maybe_init ();

   libgcc_s_resume (exc);

 }

@@ -58,8 +80,7 @@ __gcc_personality_v0 (int version, _Unwi

                       struct _Unwind_Exception *ue_header,

                       struct _Unwind_Context *context)

 {

-  if (__builtin_expect (libgcc_s_personality == NULL, 0))

-    init ();

+  _maybe_init ();

   return libgcc_s_personality (version, actions, exception_class,

 			       ue_header, context);

 }