[Bug c++/61538] g++ compiled binary, linked to glibc libpthread, hangs on SGI MIPS R1x000 systems on Linux

[pinskia at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=61538

--- Comment #6 from Andrew Pinski <pinskia at gcc dot gnu.org> ---
This is the patch which I used for glibc to fix some libstdc++ issues:
>From 2788414e4e6a548766aa7e732fc096f9f572302e Mon Sep 17 00:00:00 2001
From: Andrew Pinski <apinski@cavium.com>
Date: Thu, 1 Nov 2012 23:07:22 -0700
Subject: [PATCH] 2012-11-01  Andrew Pinski  <apinski@cavium.com>

        Bug #5086
        * ports/sysdeps/unix/sysv/linux/mips/nptl/pthread_once.c
(__pthread_once):
        Add release barrier before setting once_control to say
        initialisation is done.
        (clear_once_control): Add release barrier.
---
 ChangeLog.CAVIUM                                   |    8 ++++++++
 .../unix/sysv/linux/mips/nptl/pthread_once.c       |    2 ++
 2 files changed, 10 insertions(+), 0 deletions(-)

diff --git a/ChangeLog.CAVIUM b/ChangeLog.CAVIUM
index 8ed42ea..5975430 100644
--- a/ChangeLog.CAVIUM
+++ b/ChangeLog.CAVIUM
@@ -1,3 +1,11 @@
+2012-11-01  Andrew Pinski  <apinski@cavium.com>
+
+    Bug #5086
+    * ports/sysdeps/unix/sysv/linux/mips/nptl/pthread_once.c (__pthread_once):
+    Add release barrier before setting once_control to say
+    initialisation is done. 
+    (clear_once_control): Add release barrier.
+
 2012-10-28  Andrew Pinski  <apinski@cavium.com>

     Bug #5059
diff --git a/ports/sysdeps/unix/sysv/linux/mips/nptl/pthread_once.c
b/ports/sysdeps/unix/sysv/linux/mips/nptl/pthread_once.c
index 308da8b..c2ef264 100644
--- a/ports/sysdeps/unix/sysv/linux/mips/nptl/pthread_once.c
+++ b/ports/sysdeps/unix/sysv/linux/mips/nptl/pthread_once.c
@@ -28,6 +28,7 @@ clear_once_control (void *arg)
 {
   pthread_once_t *once_control = (pthread_once_t *) arg;

+  atomic_full_barrier ();
   *once_control = 0;
   lll_futex_wake (once_control, INT_MAX, LLL_PRIVATE);
 }
@@ -80,6 +81,7 @@ __pthread_once (once_control, init_routine)


       /* Add one to *once_control.  */
+      atomic_full_barrier ();
       atomic_increment (once_control);

       /* Wake up all other threads.  */
-- 
1.7.4.1